Control of Overeating

For many of those who have just started low-carbing, one of the best aspects of the diet is a new-found freedom from the constant need to eat. A low-carber can consume a reasonable portion of food, feel full, and not have to eat again until his or her next scheduled meal.

At least, that's true for many low-carbers. However, some low-carbers find that they still overeat, or that they continue to crave carbohydrates. What then?

One of the more interesting solutions to the overeating problem has been described by diabetes expert Dr. Richard K. Bernstein. He has observed that in some patients, Byetta (generic name, exenatide) is able to curb overeating and carbohydrate cravings. Byetta is an injectable drug that works very much like the natural gut hormone glucagon-like peptide-1 or GLP-1.


GLP-1 is one of the incretin hormones. Whenever food is eaten, GLP-1 is secreted by the L cells in the intestinal mucosa. GLP-1 has several actions:

1. It stimulates the release of insulin.
2. It inhibits the release of glucagon.
3. It slows stomach emptying.
4. It increases satiety.

When GLP-1 is given in an intravenous infusion to patients with type 2 diabetes, it is able to reduce blood glucose even in severe diabetes. Unfortunately, because GLP-1 has a half-life of about two minutes, it cannot be taken in the form of single injections. The drug Byetta is called an incretin mimetic because it is able to activate the same receptors used by GLP-1. Byetta's advantage is that, because it has a slightly different structure than GLP-1, Byetta has a half-life of about 2.4 hours.

In the treatment of diabetes, Byetta is typically given by injection twice a day, an hour before a meal is eaten. However, because of the 2.4 hour half-life, this means that Byetta cannot provide complete 24-hour control of blood glucose. For that reason, Byetta needs to be taken in combination with other oral hypoglycemic agents such as metformin and the thiazolidinediones. It is able to perform functions #1 and #2 of GLP-1, but it does not do them very well.

However, in its use for functions #3 and #4 (delay of stomach emptying and promotion of satiety), Byetta is much more promising. During a three-year open-label study of Byetta, an unexpected result was noticed. Investigators found that participants lost an average of 12 pounds over the three years, with one in four of these losing an average of almost 29 pounds.

Because of these observations, Dr. Bernstein began using Byetta to help treat overeating in patients who were in the early stages of diabetes. In Dr. Bernstein's Diabetes Solution, he says that he advises his patients to inject 5-10 micrograms of Byetta about one hour before the times when snacking or overeating typically occur. The maximum daily dosage of Byetta is 20 micrograms per day, permitting as many as four injections daily.

Patient reports indicate that Byetta reduces appetite and/or carb cravings for many people but not for all of them. There is no way to predict beforehand who will or will not respond, but it takes only about a month to determine whether a particular person is in the group that can benefit from the weight-loss aspects of the drug. If it does work, it gives the patient the opportunity to train himself or herself in the habit of eating healthy low-carb foods in moderate portions. In that way Byetta is somewhat similar to weight-loss surgery. It is able to give the patient a period of time to adapt to eating less food and making better food choices, but the use of Byetta also allows the patient to avoid the dangers of anesthesia, surgical wound healing and impaired absorption of vital nutrients.

The Ketogenic Diet and Epilepsy

The logo in the picture above belongs to the Charlie Foundation. "Charlie" is Charlie Abrahams, the son of a Hollywood producer named Jim Abrahams. In 1993, at 20 months of age, Charlie had been having up to 100 epileptic seizures a day. Although he was on several powerful anti-seizure medications, and had even had brain surgery, Charlie's seizures continued. His parents tried everything they could think of to help him. Finally they learned of an old treatment for epilepsy called the ketogenic diet. It consisted of approximately 90% fat, with adequate protein for growth and a very small amount of carbohydrate.

The ketogenic diet had originally been invented in the 1920's. Early in that decade, a physician named Hugh Conklin began to treat children with epilepsy by having them consume only water for 10 to 25 days. Amazingly, when the children resumed normal eating, many of them were found to be seizure-free for long periods of time. Although enforced fasting was a difficult treatment for these children, at that time it was considered a reasonable alternative to a lifetime of constant seizures. Eventually investigators discovered that seizure reduction could also be achieved with a diet that produced many of the effects of starvation while providing sufficient calories for survival and growth. The key was that the diet was very high in fat and very low in carbohydrate and, like starvation, it produced a large amount of ketone bodies including acetoacetate and beta hydroxybutyrate.

Low-carbers know that on a standard American diet, the tissues of the brain use glucose as their primary fuel. They also know that on a low-carb diet, after a period of metabolic adjustment, most of the tissues in the brain are able to use ketone bodies for fuel. For low-carbers, this is just an interesting fact. However, for children in the 1920's with epilepsy, it had profound implications. By maintaining a high level of ketones and a low availability of gluocose for their brains to use as fuel, many children were able to reduce or avoid epileptic seizures altogether.

Then in 1938, a new drug called Dilantin (phenytoin) was introduced. Dilantin proved to be such an effective anticonvulsant that physicians began to turn their attention to pharmaceutical interventions for epilepsy, and the dietary approach to the treatment of epilepsy was all but forgotten. By the 1990's, Johns Hopkins Hospital was one of the few places that treated epileptic children with a ketogenic diet, and even they initiated treatment on only about ten patients per year.

That's where Charlie Abrahams entered the picture. After two days on the Johns Hopkins ketogenic diet, Charlie was seizure-free. (Remember, he had been having up to 100 seizures per day.) After a month, he was off all of his seizure medication. Understandably, his parents were impressed. They used their resources and contacts to establish the Charlie Foundation in order to help other parents whose children were not responding well to standard epileptic treatments.

Fifteen years later, Charlie Abrahams himself is still doing well and can be seen to be a normal teenager in a video filmed in 2008. Because of the resurgence of interest in the ketogenic diet, in 2007 the American Academy of Pediatrics published a review article called The Ketogenic Diet: One Decade Later. The article discusses the dramatic increase in the use of the ketogenic diet for the treatment of epilepsy. Although the mechanism by which the diet reduces seizures is still a matter of speculation, the diet appears to be effective in children of different ages and can be used to treat both generalized and partial seizure disorders. About half of the children who initiate the diet are not able to follow it long-term, but among the rest, about 10%–15% of are seizure-free one year later, while another 30% experience a 90% reduction in seizures. For those who cannot follow the strict ketogenic diet, a small study using a diet that approximated Atkins Induction found that 65% of patients had a 50% reduction in seizures and 35% had a 90% reduction.

The review article as well as the website for the Charlie Foundation make fascinating reading. If you have epilepsy or if you have a child who has epilepsy, it is important to contact experienced professionals before attempting to do the ketogenic diet. It turns out to be much more complicated than just picking up a copy of Dr. Atkins' Diet Revolution and forging ahead on your own. But there appears to be lots of help available for those who would like to consider using a ketogenic diet an an additional approach to the management of difficult-to-control epilepsy.

Natural Chemicals

My training is in chemistry. Because of that, I tend to see the world as an array of chemicals, from the the cotton in my clothes to the gasoline in my car. But a comment on last week's post reminded me that in recent decades we have been trained to see chemicals in two different classifications--natural and man-made. We have been taught that natural things are by definition good and man-made things may very well be bad and could hurt us in the long run. For those of us who are interested in healthy eating, the distinctions have particular significance. In the world of low-carbing, are natural foods the safest foods? Not necessarily.

One of the natural foods we have been discussing lately is fructose. It's found in high-fructose corn syrup, of course, but it is also found in fruits and honey. Regardless of where it's found, fructose is fructose. The molecule stays the same. And the molecule fructose, when eaten in large quantities, is able to produce a fatty liver, protein glycation, and even gout.

Another natural food is potatoes. Potatoes are not recommended on low-carb diets, but some of us can't keep away from the french fries and chips. Potatoes are in the nightshade family of vegetables and contain the glycoalkaloids solanine and chaconine. These chemicals are acetyl cholinesterase inhibitors and are used to protect the potato from attack by fungus and insects. Unfortunately, they also have a negative effect on some people. They can produce joint pain and symptoms of digestive inflammation, and even mental confusion in a few cases. Cooking destroys some but not all of the glycoalkaloids in potatoes.

Whole wheat is beloved of those who promote a natural lifestyle. Wheat contains proteins called lectins, which act as a primitive immune system for a plant. When wheat is eaten by bacteria, insects, rodents or humans, the ingested lectins are able to bind to cell walls and membranes and cause the clumping of cells, as well as inappropriate cell division and hormone reactions. These effects can cause inflammation and damage to the lining of the small intestine, as well as possible autoimmune reactions if the lectins are absorbed into the circulation. Cooking or baking is able to break down some lectins but not all of them. It is interesting to note that early agriculturalists knew how to decrease lectin content by sprouting and fermenting the wheat they harvested.

Corn oil is another all-natural product that is used both in cooking and in the manufacture of margarine. Corn oil is high in total polyunsaturated fatty acids as well as omega-6 polyunsaturated fatty acids. A recent study in Sweden has shown an association between omega-6 fatty acid intake and breast cancer. A 2006 study showed that the addition of omega-6 fatty acids to prostate tumor cells doubled their growth rate in culture. Another study showed a similar result in a strain of mice that was bred to be susceptible to prostate cancer.

What does all of this mean? Is anything safe to eat? Probably not, but there are obvious risks to fasting indefinitely.

What these examples imply is that a description of "natural" is not a guarantee of safety. Not only that, it wouldn't matter if the foods described above were grown in an organic way on local farms or in the conventional way on huge industrial farms. The natural chemicals (fructose, glycoalkaloids, lectins, omega-6 fatty acids) would be there whether or not organic farming methods were followed.

Fortunately for us, experience has shown that humans are well able to tolerate small amounts of toxic substances. However, for those who are interested in following a maximally healthy lifestyle, each food needs to be considered on its own. Animals defend themselves with horns and hooves. Plants defend themselves with chemicals. Some of these chemicals are beneficial, but some are not, and it pays to be aware of the differences.

Diet Drinks, Ups and Downs

Diet drinks are one of the mainstays of the low-carb community. Diet Coke, Diet Pepsi, Diet Rite and many more provide fairly palatable carb-free alternatives to sugar-laden soda pop.

Some low-carbers drink all sorts of diet drinks and claim they have no problems with them. Others state that diet drinks cause them to gain weight or cause them to stall in their weight-loss programs, almost as if they were drinking the full-sugar equivalents. One of the ways to look at this phenomenon is to see if diet drinks cause the release of insulin.

One possibility is that the sweet taste of the diet drinks causes a cephalic or first-phase insulin response. Two 1995 studies by Teff, Devine and Engelman had normal-weight men sip and spit solutions that contained either water, aspartame, saccharin, or sucrose. Blood was drawn before and at two-minute intervals after the solutions were tasted. They found no significant increase in plasma insulin, even though the men had tasted the sweetened solutions for as long as three minutes.

Another possibility is that the presence of a sweet taste in the gut causes the release of peptides, and these in turn increase the secretion of insulin as part of a second-phase insulin response. It has recently been found that there is a TR2+T1R3 sweet taste receptor in the intestinal endocrine cells of the gut. In 2007, Margolskee et al. demonstrated that sucralose (brand name, Splenda) could activate this receptor in dishes of intestinal endocrine cells and cause the release of two incretin hormones, GLP-1 and GIP. In a whole organism, the incretin hormones would be expected to promote the release of insulin.

In 2009, Jin Ma et al. tested this hypothesis by infusing 500 ml of various solutions into the stomachs of seven healthy humans. (Putting a solution directly into the stomach bypassed any possible cephalic insulin response.) The first solution contained 50 grams of sucrose in water. The remaining solutions were: normal saline, 80 mg of sucralose in normal saline, and 800 mg of sucralose in normal saline. Of the four solutions, only the sucrose solution caused an increase in blood glucose. And contrary to the findings expected from the intestinal endrocrine cell study, only the sucrose caused an increase in GLP-1, GIP and insulin. The saline and sucralose solutions had no effect. Fujita et al. saw similar results when diabetic Zucker rats were given gastric boluses of solutions of glucose, sucralose, saccharin, acesulfame potassium, and stevia. Only the glucose solution affected the blood glucose, and only the glucose solution
increased the plasma GLP-1 and GIP levels. The artifically-sweetened solutions had no effect.

To drink or not to drink? A recent review of the literature in the American Journal of Clinical Nutrition noted that the use of nonnutritive sweeteners has increased along with the increase in Body Mass Index (BMI) in the United States. However, the authors found that if this is a cause-and-effect relationship, most of the mechanisms by which it is postulated to occur cannot be supported by current evidence. As we can see from the studies cited above, it appears that increased first-phase or second-phase insulin secretion is probably not a good explanation for any gain in weight as a result of diet drinks. As always, research is ongoing, but for now it looks as if diet drinks can be consumed without undue worry about their effect on insulin secretion and an insulin-associated gain in weight.

Blood Glucose, Cancer, and Coronary Heart Disease

Elevated blood glucose is most often associated with the symptoms of diabetes, such as retinal damage, kidney failure and peripheral neuropathy. However, the consequences of hyperglycemia are not confined to diabetics. As blood glucose values rise in nondiabetics, it is possible for them to experience an increased relative risk of cancer and of coronary heart disease as well.

In 2007, Par Stattin and colleagues published a prospective study that investigated a possible relationship between hyperglycemia and the risk of various forms of cancer. More than sixty thousand Swedish men and women with no previous history of diabetes were studied over a 13-year period. During that time approximately 2,500 cases of cancer were identified in the study group. The investigators looked at the relationship between fasting glucose levels and the risk of cancer in this nondiabetic population. Among the participants who had elevated fasting blood glucose, there were small but statistically significant increases in the relative risk for several specific types of cancer. These included pancreatic cancer, cancer of the urinary tract and malignant melanoma. In women there was an increased risk of endometrial cancer. Among women less than 49 years of age, there was an increased risk of breast cancer. On the other hand, in men there was actually a decrease in the risk of prostatic cancer as fasting blood glucose levels rose.

Nondiabetics were also shown to have an association between glycemic control and the risk of coronary heart disease in a 2005 study published in the Archives of Internal Medicine. In a prospective study, investigators followed 1321 nondiabetic adults to assess a possible relationship between the level of hemoglobin A1c (HbA1c) and the incidence of coronary heart disease.

Hemoglobin A1c measures the percentage of glycated hemoglobin in a patient's red blood cells. The HbA1c value provides a picture of a person's average blood glucose control for the previous 2 to 3 months. The normal range for HbA1c in people without diabetes is
4% to 6%. For diabetics, the American Diabetes Association recommends that the HbA1c be maintained at 7.0% or less.

The nondiabetic patients in the coronary heart disease study were followed for 8 to 10 years. In order to remove possibly confounding variables, when the data was analyzed, it was adjusted for age, race, sex, BMI, blood pressure, LDL cholesterol, HDL cholesterol, triglycerides and smoking status. The adjustments for these risk factors allowed the investigators to examine whether hyperglycemia might provide an independent risk factor for coronary heart disease. They found that when HbA1c was below 4.6%, the adjusted data showed no apparent relationship between glycemic control and an increased risk of coronary heart disease. However, as the HbA1c rose above 4.6%, the adjusted data showed that not only did the risk of coronary heart disease rise, but it did so at an ever-increasing rate. The study found that the risk of coronary heart disease in nondiabetics rose 2.4-fold with every 1% increase in HbA1c above 4.6%.

Findings similar to those seen in both of these studies have also been reported by other investigators, and references can be found within each paper. However, it is important to remember that correlation does not equal causation. The relationship between increased blood glucose in nondiabetics and the incidence of cancer or the incidence of coronary heart disease may rest upon variables that are not as yet defined. However, it is worth noting that it may be important even for nondiabetics to keep an eye on their fasting blood glucose and their HbA1c.

Glycosylation and Glycation

In light of recent discussions about increased protein intake producing a rise in blood sugar, this seems to be a good time to repeat a post from 2008. It helps explain why elevated blood sugar can present potential long-term health risks.
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When proteins are assembled in our cells, sometimes specific sugar molecules are attached to them in carefully-defined ways. This is called glycosylation. Enzymes add the sugar molecules to help proteins fold properly and to route proteins to various places inside and outside the cell. Glycosylation patterns also help our bodies to distinguish proteins that are "self" versus "not-self" and are useful in immune responses. Glycosylation results from controlled reactions and is important for our biochemical wellbeing.

When we have glucose in our blood (and if we're alive, we do), sugar molecules are also added to proteins in a random fashion. The random addition of sugar molecules to proteins is called glycation. If only single glucose molecules have been added to a protein, when the blood sugar level drops, the glucose can detach and the protein will again be normal. But if blood glucose remains high, more sugars will be added. These will rearrange and crosslink, eventually producing something called an Advanced Glycation Endproduct or AGE. One example of an AGE is hemoglobin A1c, the form of hemoglobin found elevated amounts in the red blood cells of poorly-controlled diabetics. Evidence suggests that many other proteins in our bodies are also converted into Advanced Glycation Endproducts by elevated blood sugar. Glucose and fructose in the blood interact with and crosslink these other proteins in our bodies, forming AGEs that accumulate in our eyes, kidneys, arteries, nerve endings, joints and skin. The end result of AGE accumulation can be retinal disease, kidney failure, atherosclerosis, peripheral neuropathy, frozen joints and cracked skin.

Although our bodies have mechanisms to cope with the identification and disposal of AGEs, the AGEs gradually accumulate and stiffen our tissues. The elasticity of youth is slowly replaced by the physical degeneration of old age. In other words, crosslinked AGE proteins produce in us the symptoms we associate with old age. This happens in all people, but the process is made worse and happens more quickly in the presence of elevated blood sugar.

(The illustration is taken from the cover of the journal Science, March 23, 2001.)

How Can Eating Excess Protein Raise Blood Glucose?

It is almost an article of faith among low-carbers that the low-carb lifestyle is able to lower blood glucose values in diabetics and pre-diabetics. It would be logical to assume that the lower the carbohydrate intake, the lower the corresponding blood glucose. But recent observations in a limited sample of people who were doing something very close to zero-carbing suggest that this is not necessarily the case.

Donald K. Layman has done some interesting work on the effect of dietary protein on glycemic control that may help explain this phenomenon. In an article in The Journal of Nutrition, he presents a diagram of the glucose-alanine cycle, which appears in modified form above.

For those who are not familiar with this type of diagram, here is a brief explanation. Ingested protein enters the gut and is digested into amino acids. The amino acids are taken up in the blood and proceed to the liver, where many of them are metabolized. However the branched-chain amino acids leucine, isoleucine and valine are unique. Although they constitute 15-25% of protein intake, they experience very little metabolism in the liver. Most of the branched-chain amino acids, abbreviated BCAA, continue to move through the circulation and are eventually absorbed by muscle cells.

In muscle cells the branched-chain amino acids have two possible fates. First, when branched-chain amino acids enter a muscle cell, they promote protein synthesis. Our muscle tissue is continually undergoing repair, and because of this each of us has an individual daily protein need. If sufficient high-quality protein is consumed, this repair is able to take place without loss of lean muscle tissue.

Second, if there is an excess of amino acids in the muscle cells, the surplus branched-chain amino acids enter the pathway of energy production. In order to do this, they must have their amino group (NH₃)removed in a process called transamination. The amino group from a BCAA is transferred to a molecule called alpha-keto-glutarate to form the amino acid glutamate. Next, another transamination transfers the amino group from the glutamate to pyruvate, transforming the pyruvate into the amino acid alanine. The alanine leaves the muscle cell and travels to the liver, where it is turned into pyruvate by removal of the amino group, and then the pyruvate is turned into glucose by gluconeogenesis. The liver sends the newly-synthesized glucose into the blood, where it can be taken up by muscle cells and broken down once again into pyruvate. Each pyruvate is ready to accept another amino group from one of the branched-chain amino acids, and the cycle repeats itself until the branched-chain amino acids have been used up.

The glucose-alanine cycle explains why it is possible to have an elevated blood glucose while eating essentially only meat and fat. Normally, leucine signals the muscle cells to synthesize protein and maintain lean body mass. When an excess of branched-chain amino acids is available, leucine serves as a metabolic signal to muscle cells telling them to upregulate their use of BCAA as a fuel, while simultaneously downregulating their use of glucose as a fuel. Any glucose that appears in the cell is preferentially broken down into pyruvate, which is used to accept excess amino acid nitrogen (NH₃ groups) and allow them to be removed them from the cell in the form of alanine. In the liver, the alanine is recycled into glucose, and the glucose is returned to the blood until it is no longer needed to mop up excess NH₃ groups in peripheral tissues.

If this pathway is correct, it shows that excess amino acids not only provide the raw materials for glucose synthesis in the liver, but they also require additional glucose synthesis in the liver in order to allow branched-chain amino acids to be converted into energy.

Metabolic regulation is a huge topic, and this post presents only a small piece of it. Once again, please do not modify your lifestyle in accordance with what you read here. In the overall context of a human organism, it may be incomplete or even incorrect. However the glucose-alanine cycle does provide a possible explanation for what some people have seen with regard to a higher-than-normal blood sugar while eating essentially zero carbohydrates.

Observations on Protein Intake in Low-Carbers

Last week I asked if people doing low-carb or zero-carb might be willing to test their blood glucose before and after meals and report their results. Many finger sticks later, we have a few tentative observations. Please note, this was NOT a scientific study in any way. Don't change your life or your eating habits based on what you read here. The purpose of this post is to consider ideas and to raise possibilities, particularly if you have been having trouble succeeding on low-carb or zero-carb. That said, here are the patterns that seemed to emerge from the data.

1. Some people, particularly people over 50, do have an increase in blood glucose following meals that are either entirely or mostly meat and fat. Dr. Bernstein says the optimum level of blood glucose is 83 mg/dl. For zero-carbers over 50, the fasting blood glucose was often somewhere between 95 and 110 mg/dl and could even go as high as the high teens. For long-time low-carbers over 50, fasting blood glucose was usually somewhere in the 80's. In both low-carbers and zero-carbers over 50, it was not unusual to have a 30-40 mg/dl rise in blood glucose after consuming a large amount of protein, such as a 12-ounce ribeye. Because protein is slowly digested, blood glucose levels sometimes stayed elevated for three to five hours or longer. It is important to remember that at blood sugars above about 100 mg/dl, insulin is secreted and its presence keeps fat in the fat cells. This may explain why low-carbers over 50 have such a hard time losing weight if they eat as much protein as they want. Insulin levels stay elevated for long periods, forcing most of what they eat into storage, and keeping it there until insulin levels finally come down again.

2. Most people under age 50 do not have a rise in blood glucose following a meal, even a large meal, that is mostly meat and fat. I had three participants in the under-50 group whose blood sugars stayed approximately in the 80's following meals ranging from a 1/3 pound hamburger to a ribeye steak. Two of them told me that they occasionally see rises to near 100 mg/dl, but often there is no rise at all.

3. Decreasing protein intake in two participants over 50 to the amount recommended at Blood Sugar 101 caused a decline in average pre-meal blood glucose to the low 90's and post-meal glucose values between about 90 and 110 mg/dl. In fact, both of them started losing weight again after several months of eating as much protein as they wanted and gradually gaining weight.

4. And then there were the outliers, which I shall address below.
Two participants occasionally experienced a fall in blood glucose following a low-carb meal. Neither has been diagnosed with diabetes. Nevertheless (unless they were eating more carbs than usual), their blood glucose sometimes declined after they had eaten a low-carb meal of meat and vegetables. One was a man and one was a woman. One was under 40 and one was over 60. The woman, SC, suggested to me that it might have something to do with the fact that she is a super-taster. When I checked with the other one, who happens to be Jimmy Moore, it turned out that he is also a super-taster. Just to be sure, I checked with super-taster Cleochatra. She did not have blood glucose data to give me, but she said, "I can tell when I've eaten a carrot, even when it's been hidden in a dish, because my stomach is growling within minutes and I want to dive face first into various vats of puddings. I can say in all honesty, artificial sweeteners made me starve...and when I'm VLc I feel fantastic. No woobly or feelings of hunger at all." Later she specified that Splenda and the sugar alcohols are the artificial sweeteners that affect her.

[In the comments, Mariasol asked what made a person a super-taster. Although there are tests for this ability, I simply used an informal question as a criterion: If I poured out five unlabeled dixie cups of Diet Rite, Diet Pepsi, Diet Coke, Coke Zero and Splenda Coke, could you correctly label each cup with the brand, based on taste alone? If your answer to that question is yes, you probably are a super-taster. Subsequently, I have been told that when a super-tasters are cooking something and then add in the salt, they can smell the salt. Just like everything else in this post, the super-taster information has been collected in a non-rigorous manner, so please do not take it as settled science.]

From a limited sample size of three, I can speculate that super-tasters are the ones whose insulin is on a hair-trigger. As soon as they eat, or maybe even before they eat, they secrete enough insulin to nail any food that might appear in the stomach. And if that food happens to be diet soda, it's possible that the insulin secretion occurs anyway. This can either trigger hunger pangs, or if the diet soda is consumed continuously, can keep insulin levels relatively high and thus prevent fat mobilization and weight loss.

All of this is anecdotal. It didn't come down on tablets at Mt. Sinai, so various parts of it could be wrong. But I present it as something worth thinking about in the context of a low-carb lifestyle.

Very many thanks to Cleochatra, ES, D, Jimmy Moore, K, KM, LR, SC, SG, SO, V, VS, P and U for providing data that was used in this blogpost.

Protein Intake and Blood Glucose Levels

Low-carbers know that when a person eats foods that contain carbohydrates, his blood glucose will rise. As the pancreas releases insulin in response, the blood glucose levels will gradually return to normal.

What happens when a person eats protein? Insulin is released in response to protein as well, enabling the amino acids to be removed from the blood and stored in the tissue. The cells don't know the insulin is there to remove amino acids from the blood, so they will take up glucose from the blood as well. To prevent hypoglycemia, the liver gradually releases glucose into the blood to replace the glucose that has been stored.

In the graph above, the white lines show us that when a normal person eats 50 grams of protein, the blood glucose remains the same out to five hours after the meal, even though a significant amount of insulin has been released. The person with type 2 diabetes is represented by the yellow lines. His blood glucose levels start out at a much higher level, but when he eats 50 grams of protein, his blood glucose levels also stay steady out to two hours and then actually begin to drop because a great deal of insulin has been released. These graphs are found at Metabolic response of people with type 2 diabetes to a high protein diet.

It is important to realize that the response to protein in both the diabetic and non-diabetic person are happening in people who are not low-carb-adapted. Low-carbohydrate-adapted people are able to make all the carbs they need through gluconeogenesis. Their brains and muscles have switched over to the use of ketones and fatty acids for fuel, and the 40 or so grams of glucose they need for glucose-requiring tissues are readily converted from glycogenic amino acids and the glycerol backbones of triglycerides. So, what happens when a person who eats very low carbs has a meal of protein? For a rather extreme example, look at the graph below.

Lex Rooker is a very dedicated and meticulous individual who posts at the Raw Paleo Forum. (In no way do I either support or condemn what Lex does regarding his diet, but his journal certainly makes fascinating reading.) For about two years, Lex ate a single daily meal in the afternoon, at the time marked by an asterisk on the graph. This meal contained 150 grams of protein and consisted of 68% fatand 32% protein. As you can see, his blood glucose remained rock-steady at about 106 mg/dl throughout the day. But a couple of hours before he ate, it would drop to 95 mg/dl. After he ate a meal consisting solely of meat and fat, his blood glucose would rise about 25 mg/dl, returning to baseline in about four hours. (The graph shows a rise of 15 mg/dl, but he refers to the amount of the rise several times, so this may be an error in the graph.)



At one point Lex decided to switch things up a bit. He kept his calories the same, but ate only 90 grams of protein per day, making the ratio 80% fat and 20% protein. His baseline blood glucose dropped into a range between 68 and 78. After his single daily meal of meat and fat, his blood glucose would rise about 15 mg/dl, though it would take longer than before to come down to baseline. It appears that decreasing the amount of protein intake also decreases the amount of glucose released into the blood of a low-carb-adapted person.

People who are not low-carb-adapted do not do much gluconeogenesis because they get plenty of glucose from their diet. People like Lex Rooker who eat no carbs at all, apparently do quit a bit of gluconeogenesis. Low-carbers fall somewhere in between those two points. This provokes a question to which I do not currently have an answer: What does a normal blood glucose curve look like in a low-carber? If he chooses to eat only meat and fat at a particular meal, does his blood glucose rise or does it stay steady? If he eats a few carbs with each meal, does it rise less, or does it rise more than it would without the carbs?

In other words, this time it's not a blog, it's a bleg. If anybody has data on what a normal (or abnormal) daily blood glucose curve looks like in a low-carber, would you please share that information in the comments? Thanks!

(If any of the graphs are too fuzzy to read, just click on them and you'll get a clearer version.)

Glycogen Stores Energy

Adipose or fat tissue stores most of the body's energy reserves in the form of triglycerides. The body is also able to store a limited amount of energy as carbohydrates, and it does it in the form of glycogen.

Glycogen is a large, complex molecule made up of branched chains of glucose molecules. The illustration above, found at Wikipedia, shows a cross section through the middle of a spherical glycogen molecule. At the center is a glycosyltransferase enzyme. The enzyme takes glucose-6-phosphate (the form of glucose found inside a cell) and strings it together as long, branched chains. In the picture above, each tiny circle represents a glucose molecule. The glycogen molecules are therefore large polymers of glucose which are then packed together and stored in granules in the cytosol of liver and muscle cells.

Glycogen makes up as much as 10% of the weight of the liver and represents about 100 grams of glucose in the adult human. Glycogen in the liver can be broken down first into glucose-6-phosphate and then into glucose. In the form of glucose it can be released back into the circulation. In a previous post we have seen that release of glucose from liver glycogen is the body's chief means of maintaining a normal blood sugar between meals.

Glycogen can also be stored in skeletal muscle, as illustrated in the figure below.


When glucose is present in the blood (and in a living person, it always is), a muscle cell is able to take up the glucose both actively and passively. Once the glucose is inside the muscle cell, the glucose molecule is phosphorylated. This adds a large ionic group which makes it impossible for the glucose to diffuse back out of the muscle cell. The phosphorylated glucose then has two possible fates.

1. It can proceed directly into glycolysis and be turned into pyruvate. If there is enough oxygen available, the pyruvate will enter the mitochondria and be turned into lots of ATP, the energy currency of the cell. If there is not enough oxygen available, the pyruvate will be turned into lactic acid plus a little ATP. The buildup of lactic acid produces a sensation of pain, and the pain will continue until the lactic acid diffuses back out of the muscle cell, a process which takes about an hour.
   
2. Alternatively, the phosphorylated glucose may instead be stored in the muscle in the form of glycogen. Muscle glycogen makes up only 1-2% of the weight of skeletal muscle, but because the body contains so much skeletal muscle, the total quantity of muscle glycogen in an adult is about 200 grams.

What makes muscle glycogen different from liver glycogen is that when muscle glycogen is broken down, it cannot leave the cell. Muscle cells lack the enzyme that removes the large ionic phosphate group from the glucose, and the glucose cannot be returned to the blood. For that reason, the phosphorylated glucose must be used inside the muscle cell. What then?

No problem. The phosphorylated glucose feeds right into the glycolytic pathway inside the muscle cell, where it is turned into pyruvate and lots of ATP or into lactic acid and a little ATP, depending on the amount of oxygen available to it.

When we hear about carb loading for athletic events, it is tempting to think that most of the energy in our muscles comes from carbohydrates. It does not. There is only a little glycogen stored in each muscle cell, and it is easily exhausted. Compare the 200 grams of total muscle glycogen with the pounds of fat available in a healthy individual, and it becomes obvious that muscle cells must use free fatty acids for most of their energy. This is illustrated on the right side of the illustration above. As seen previously (How Are Fats Metabolized?), once the free fatty acids are inside the cell, they are broken down very efficiently to produce much more ATP than could be obtained from an equal number of glucose molecules. However, when an extra burst of energy is needed, muscle cells are able to use the glucose they have stored in glycogen granules to supply a little more ATP than they would normally receive from using fatty acids alone.

Low-Carb Doesn't Work!

Low-carbers hear it over and over. "I can't get to goal." "Nobody I know has reached goal." "Almost all the low-carb gurus are obese."

There are many reasons for weight loss to slow or stop while low-carbing. Read any of Dr. Atkins' books or follow any of the low-carb websites and you will find lots of possible explanations, including factors like low thyroid function and yeast infections.

Another reason for failure to lose weight and for weight regain on low-carb is seldom mentioned. An example is pictured above--low-carb substitutes for high-carb foods. (The picture is taken from a post about a low-carb sponge cake at Cafe Nilson.) But low-carb substitute foods are still low-carb! Why should they interfere with a low-carb diet?

A 2005 study on binge eating in rats may give some insight. In one experiment, the rats were separated into two groups, food-sated and food-restricted. They were then exposed to several food choices, including normal rat chow and a cereal called "Choc and Crisp" which appears to be a German version of Cocoa Krispies. The food-restricted rats took about three minutes to find the rat chow, and they ate about half a gram of it. By contrast, they found Choc and Crisp in only ten seconds and when they reached it, they ate nearly five grams of it.

As expected, the food-sated rats were not interested in the rat chow. They took about 20 minutes to wander over to it and when they got there, they didn't eat it. However, even though these rats had already eaten until they were full, the food-sated group took one fiftieth of that time (25 seconds) to find the Choc and Crisp, and once they reached it, they ate 3 grams of it, or 60% of the amount the food-restricted rats had consumed.

To confirm these responses, each rat was put on a runway with a food-filled box at the other end. When the goal box contained rat chow, it took the food-sated group about 40 seconds to reach the goal, while the food-deprived ones took about 10 seconds. Not surprising. However, when the goal box contained Choc and Crisp, both groups made the trip in about five seconds, though the food-restricted group was a little faster. One might expect that after the first day, the rats would be less excited about the Choc and Crisp, but the time needed to reach the goal boxes persisted over ten consecutive trial days.

The obvious conclusion is that if you feed pet rats with Cocoa Krispies, they will probably get fat. A less obvious inference might be that if a low-carber is freqently exposed to low-carb versions of very enticing high-carb foods, he or she will probably eat those foods to excess. The rat study indicates that the easy availability of very palatable foods may shut off the body's ability to adjust food intake to match energy expenditure. What happens in a rat does not necessarily happen in a human, but their tendency to eat much more of a very palatable food is definitely something to consider when low-carbers have a hard time reaching or maintaining their goal weight.

How Are Fats Metabolized?

In a previous post we saw that the fats we eat are made up of a group of molecules called tri-glycer-ides--three fatty acids covalently bonded to one glycerol backbone. In a subsequent post we learned that triglycerides are absorbed, packaged and transported to the cells of the body through the circulatory system. In muscle cells these triglycerides can be used for energy, and in adipose tissue (fat cells), they can be stored for future use.

What happens when it is time to use the fat we have stored in our bodies? The first thing that must happen is that insulin levels must be low. In the presence of low insulin, the hormones glucagon from the pancreas or epinephrine from the adrenal glands will stimulate the activity of hormone-sensitive lipase (HSL). Hormone-sensitive lipase (plus another enzyme called diacylglycerol lipase) will convert a triglyceride stored in a fat cell back into one glycerol molecule plus three fatty acids.

Once the fatty acids are detached from the glycerol backbone, they are able to dissolve in the cell wall of the adipocyte or fat cell. From there they are able to diffuse passively out of the adipocyte back into the blood, where they attach themselves to serum albumin and are carried throughout the body. The free fatty acids are able to diffuse passively into tissues as well.

Once inside one of the body's cells, the free fatty acid is activated with a "handle" called CoA. (Pronunciation note: CoA rhymes with "No Way." It does NOT rhyme with Boa.) The fatty acid plus its handle is called acyl-CoA. The acyl-CoA heads for a mitochondrion, a small organelle that functions as the powerhouse of most cells. Once inside the mitochondrion, the acyl-CoA is dismantled, two carbon units at a time. Each time a two-carbon unit is released, energy is produced from the breaking of the covalent bonds. Not only that, the two-carbon units themselves enter something called the TCA or tricarboxylic acid cycle where they are broken down further to produce carbon dioxide plus even more energy.

The energy released by all of these chemical reactions eventually results in the formation of many molecules of adenosine-5'-triphosphate or ATP. ATP molecules are the energy currency of the cell. The energy contained in ATP molecules is used for activities such as building the tissues the body needs, fueling the reactions that enable the body to move, and coordinating the activities the body needs to stay alive.

Did you ever wonder why robots need some sort of external or rechargeable power supply but people do not? The robot relies on electricity for its energy source. People, by contrast, rely on ATP for their energy and, amazingly enough, that ATP can be produced from something as simple as the fat they eat for dinner.

The Swedes Are Eating More Butter!

The graph above shows tons of butter (ton/år) sold per year in Sweden. From April 2007 to April 2008, sales of butter in Sweden went up by 13%. Therein lies a tale.

Doctor Annika Dahlqvist was a family practitioner at the Njurunda clinic in Sweden when her daughter, a physician in training, took part in a low-carbohydrate dietary study. The results were so impressive that Dr. Dahlqvist tried the low-carb diet for herself. She was pleased that she was able to lose weight, and she also noticed that her problems with gastrointestinal inflammation and fibromyalgia were significantly improved. She began recommending a low-carb, high-fat (LCHF) diet to her patients who suffered from type 2 diabetes and obesity.

The idea of a low-carb, high-fat way of eating was no more welcome in Sweden than it has been in the United States. In December 2005, the chairman of the Swedish National Association of Dieticians made a formal complaint to the Swedish National Board of Health and Welfare, questioning Dr. Dahlqvist’s low-carb dietary advice and suggesting that it might jeopardize the safety of her patients. Dr. Dahlqvist was threatened with the loss of her medical license.

Although Dr. Dahlqvist’s LCHF diet was quite compatible with a traditional Atkins-type diet, she stopped treating patients and instead began working on a blog and giving lectures to spread the word about LCHF.

Flash forward to January 17, 2008.

Professor Christian Berne, one of Sweden’s leading diabetes experts, had carefully investigated the case against Dr. Dahlqvist and presented his findings to the Swedish National Board of Health and Welfare. He said, “...a low-carbohydrate diet can today be said to be in accordance with science and well-tried experience for reducing [obesity] and type 2 diabetes...a number of trials has shown no effects in the shorter run and that no evidence for it being harmful has emerged in systematic literature researches performed so far. [There is] no scientific support yet for treatments in excess of 1 year. A thorough evaluation of long time treatment results is therefore an important demand on the practitioner.”

By objecting to the low-carb, high-fat diet, the chairman of the Swedish National Association of Dieticians had inadvertently given it validation. In fact, because of the governmental investigation into the scientific support for LCHF, the diet was approved as an alternative approach for the treatment of type 2 diabetes and obesity. New Board guidelines are expected to be completed by autumn of 2009.

As for Dr. Dahlqvist, she continues to lecture, to blog, and to gain in popularity in her native land. In 2008, Radio Västernorrland listeners chose her as Personality of the Year. The seventy percent who voted for her said, “...she stood up against the Health and Welfare and Food Administration's current dietary recommendations, campaigning instead for a diet she believes in—low in carbohydrate but high in natural animal fat.”

Even more impressively, Swedish consumers have started to consider whole milk and butter more natural and healthful than reduced-fat products and are now changing their habits to buy more of the former and less of the latter. There are still plenty of dietary traditionalists in Sweden, but for some people at least, butter is now a health food.

What Happens to the Fat We Eat?

(The illustration is a simplification of a figure in the 2007 Encyclopedia Brittanica. If it seems too fuzzy to decipher, click on it to see a clearer version.)

For the low-carber, fat is an important macronutrient. What happens when we eat fat?

One of the important aspects of fat is that it is not water-soluble. In order to begin the digestion process, the liver makes bile, which in collected in the gallbladder and is secreted into the small intestine. The bile acts as a detergent. The bile salts in it have a lipophilic side, which binds to the fat droplets, and a hydrophilic side, which suspends the droplets in the watery mixture of the food we have just eaten.

The triglycerides or fats in the suspended droplets cannot be absorbed by the intestine. To accomplish absorption. the pancreas secretes an enzyme called pancreatic lipase into the small intestine, Pancreatic lipase breaks down each triglyceride molecule into two free fatty acids plus a monoglyceride. "Mono" means one, and in this case it means that one of the fatty acids remains attached to the original glycerol backbone. When the triglyceride is broken down into subunits, it is able to pass into the absorptive cells of the intestinal mucosa. After the three subunits have transited the wall of the intestine, the fatty acids are added back to the glycerol backbone and they form a triglyceride once more.

Inside the cells of the intestine, triglycerides are packaged into chylomicrons. Chylomicrons are large diameter (75-1200 nanometer) particles that contain a bit of protein, a bit of cholesterol and lots of triglycerides. The chylomicrons are not secreted directly into the blood but into the lymphatic system. They eventually arrive at the thoracic duct and then are deposited into the blood at the left subclavian vein. Once they enter the blood, they are transported into capillaries and are able to reach the entire body.

One of the proteins in a chylomicron is called apo C-II. This protein has the ability to activate an enzyme called lipoprotein lipase or LPL. Lipoprotein lipase resides on the capillary walls of tissues that have a high requirement for triglycerides, such as cardiac muscle cells, skeletal muscle cells and fat (adipose) cells. The activated lipoprotein lipase acts on the triglyceride molecules (called triacylglycerols in the illustration above) stored inside the chylomicron. It hydrolyzes or breaks down the triglycerides into two fatty acids plus a monoglyceride. Just as we saw in the intestine, intact triglycerides cannot pass through the cell walls, but when they are hydrolyzed into subunits, they can be absorbed into the cells. Once inside, they can be used for energy in the muscle cells or reassembled into triglycerides and stored in the adipose cells.

When we eat a piece of bacon, we start with fat and end with fat (or for the low-carber--energy from the fat). But, as you can see, there are may steps involved in getting from the beginning of the process to the end.

What Is Fat?

Low-carbers spend lots of their time thinking about fat, both in terms of the excess girth on their bellies and hips, and as an important macronutrient. Although fat is a perfectly natural substance, it may surprise you to know that fat is a chemical.


In chemical terms, fats are referred to as triglycerides. They are composed of two types of subunits. The first subunit, glycerol, is shown above. Although the glycerol portion is not the most important subunit of a fat, it is the root of its chemical name, triGLYCERide. Glycerol has a three-carbon backbone, depicted by the vertical line of C's in the figure above. The active groups in glycerol are the -OH or hydroxyl groups.

The other subunits are called fatty acids. There are three of them in each fat molecule; hence the prefix TRIglyceride. In the example above, each fatty acid contains a chain of carbons represented by a horizontal row of nine C's. In real life, the length of the chains can be from four C's to twenty eight C's. The chains do not have to be the same length within the triglyceride--any assortment is possible. The active group in the fatty acids is known as a carboxylic acid and is also shown above.

The active groups of the three fatty acids are joined to the active groups of the glycerol backbone though a process called esterification. For those who are interested in the enzymatic reactions involved, they are described here. At any rate, three fatty acids attached to one glycerol backbone produces a TRI-GLYCER-ide, a triglyceride, which is one molecule of fat.

That's probably enough biochemistry for this time. There will be more fascinating facts about fats in later posts. :-)

Be Encouraged!

As most of my readers know, low-carbing is a lifestyle, not a quick weight-loss diet. Early in the process of low-carbing, weight is often lost rapidly, and some of the health improvements come right away. But as weeks move into months move into years, changes come more slowly and more gradually. Reading a diary or meeting an old friend will be a reminder that the low-carb life is better, but day-to-day excitement gradually morphs into an overall feeling of wellbeing.

As low-carbing becomes a way of life, what used to be a black-and-white eating plan begins to become shades of gray. What about eating a slice of Smart Carb bread instead of using a lettuce wrap on my sandwich? I miss bread, and this bread even contains exta (incomplete) protein. Could I substitute one or two low-carb Monster Energy drinks for a couple of bottles of water? They sure taste good and give me a mental and physical boost after all.

There are all sorts of low-carb substitutes for high carb foods. There are many vendors ready to sell them to us, and lots of cookbooks to show us how to make them ourselves. We see low-carb forums with large areas devoted to recipes. And if we try low-carb substitutes, in the short term it very often does not hurt. But what happens in the long term?

In April 2009 there was a Nutrition & Metabolism Society conference in Charleston, South Carolina. Jimmy Moore attended and posted pictures of some prominent low-carbers on his menus blog. Please check out the pictures of low-carb experts Laura Dolson and Dr. Mary Vernon. Another low-carb expert, Dana Carpender, also seems to be having weight issues. Jimmy Moore himself has recently reported that he weighs 246 pounds (an obese-level BMI of 30.7) with a body fat percentage (measured on a bathroom scale) of 31.5.

How could this be? These are prominent low-carbers. Please click on and scroll through the websites of Laura Dolson, Dr. Mary Vernon--note the array of fruit across the top, Dana Carpender and Jimmy Moore's menus blog for a clue.

Does this mean that low-carbers are doomed--doomed to gain weight in the long run? No. It does mean that the basic low-carb formula of complete protein, healthy fat and a few low-carb vegetables is hard to maintain over time. Dr. Michael Eades recently had a blogpost that graphically demonstrated that two groups of people living under similar circumstances could have drastically different outcomes for health and longevity. The hunter-gatherers had periods of starvation and fairly short lifespans, but were healthy in most respects. The agriculturalists had access to the same array of animal proteins, but they preferred to eat carbs. They were willing to suffer from increased infant mortality, painful defects in bone formation, dental cavities and bone infections in order to get a high percentage of calories from carbs rather than animal sources.

The pull of carbs and carb-replacements is strong. For one thing, they taste good. For another, the culture we live in encourages high-carb eating. But for those who are hanging in there and eating complete protein, healthy fat and low-carb vegetables, keep up the good work! In the long run, you're doing what is best for your body and in the long run, you will reap the rewards.

Not All Proteins Are Created Equal

In the previous post we learned that eating 30 grams of protein per meal can increase fat loss, preserve lean muscle, prevent osteoporosis and improve the symptoms of type 2 diabetes. But protein can come from many different sources, including meat, eggs, dairy products and plants. Does the source of dietary protein make any difference?

In a word--yes. Proteins are linear molecules made of building blocks called amino acids. Proteins are synthesized within cells by an organelle called a ribosome that reads the "recipe" for each particular protein from another linear molecule called RNA. As the ribosome reads the RNA, it looks in its immediate vicinity for whichever of the twenty different amino acids is called for next in the sequence. If the ribosome comes to a point in the RNA "recipe" where the corresponding amino acid cannot be found, the ribosome falls off the RNA and synthesis of the protein stops. Until there is enough of the missing amino acid, that specific protein cannot be made.

Where does the missing amino acid come from? Some amino acids like alanine, glutamate and asparagine, can be made by our bodies. Unless there is an inborn error of metabolism, these amino acids are present in abundance. However, other amino acids like lysine, methionine and tryptophan cannot be made by the human body. These are called essential amino acids and they must be consumed as part of the diet. If any essential amino acid is not consumed in sufficient quantity, its absence shuts down much of the body's protein-synthesis machinery.

Cereal grains such as corn, millet, rice and wheat are typically low in the amino acid lysine. Even though a person consumes many grams of protein in the form of cereal grains, the low abundance of lysine will prevent his or her body from making many of the proteins it needs for growth and repair. Legumes such as beans and peanuts are low in the amino acid methionine. Eating lots of beans or peanuts will provide lots of protein, but when the plant protein is broken down into its amino acids and these are then used for human protein synthesis by ribosomes, the ribosomes will be unable to find enough methionine to produce the proteins the body needs to sustain itself. When a food source is deficient in one or more essential amino acids, it is said to contain incomplete protein. Incomplete protein can be used as a source of calories or energy, but it is inefficent in meeting the body's need for human protein synthesis.

It is possible to mix plant sources of protein such as corn and beans in order to obtain a better overall amino acid profile. However, the complementary sources must be consumed within several hours of each other or the beneficial effect will be lost. The complementarity must also be well-understood. For instance, almonds are low in lysine and methionine, so addition of cereal grains or legumes to almond protein will still result in poor protein nutrition. Another aspect to consider is the fact that plant sources of protein are often more difficult to digest than proteins found in animal sources such as whey, meat or eggs. If the plant products are refined, digestibility is improved, but nutritional quality is lost.

Animal sources of proteins typically have a much better balance of essential amino acids than plants do. When you think about it, that makes sense. Plants do not use their proteins to make blood, muscles or organs. Plant proteins are used for different funtions, and the amino acid profiles of those proteins are unique. On the other hand, animals are similar to people in many ways, and their proteins require about the same percentage of amino acids that are required to make proteins having similar functions in humans. Good sources of animal protein include whey protein, casein (cheese), eggs, meat and fish. An interesting comparison of protein quality can be found here. As the chart in that link indicates, plant protein from soy does provide a complete array of amino acids. However, because consumption of soy products may be associated with alterations in hormone levels, they should be used with caution.

Protein is an important macronutrient. It has many beneficial primary and secondary effects, but if the protein consumed is not of high quality, i.e., if it is not complete protein, the body will not be able to use it effectively to make and repair skin, nails, hair, bone and muscle.

It's What's for Breakfast, Lunch and Dinner

Normally the topics of discussion in this blog center around carbohydrates. But for something completely different, this time we'll discuss another macronutrient--protein. Recently Donald Layman published an article in Nutrition & Metabolism entitled Dietary Guidelines Should Reflect New Understandings about Adult Protein Needs. His findings are so interesting that I've decided to summarize them here. Links that back up each point can be found in the list of references at the end of his article.

Layman begins by discussing the fact that protein has traditionally been thought of as an expensive nutrient. While that's true in the context of managing animals in a feedlot, it is a little less true in a human society where families are willing to pay $5.00 for a box of breakfast cereal. Nevertheless, because we have been conditioned to think in terms of eating small amounts of protein, it is important to establish how much protein is enough.

The Institute of Medicine, Food and Nutrition Board, has established a recommended daily allowance (RDA) between 0.36 grams and 1.1 grams of protein per pound of total body weight. The important aspect of the protein RDA is that it is proportional to current body weight. It is not a percentage of daily caloric intake. In other words, a man who weighs 200 pounds needs to eat a minimum of 72 grams of protein daily. It doesn't matter if his typical caloric intake is 3000 calories per day or if he is dieting and eats only 1000 calories per day. Regardless of his total caloric intake, he should be careful to consume at least 72 grams of protein every day.

Layman points out that the Nutrition Board has not identified an upper risk limit for the amount of protein a person can consume in a day. In other words, a normally healthy person should be able to eat as much protein as he or she wants to. With that in mind, let's take a look at some of Layman's observations in this article.

1. Protein provides a greater satiety value than fats or carbohydrates and reduces food intake at subsequent meals. This effect is seen when protein intake is over 30 grams at a meal, is strongest when the protein is consumed at breakfast and is weakest when it is consumed in the evening.

2. Compared with high-carbohydrate/low-fat/low-protein diets, weight loss diets with higher protein increase thermogenesis and increase the rate of fat loss. When combined with exercise, weight loss diets that are rich in protein can reduce lean tissue loss from 35% to less than 15% and protect from bone loss as well.

3. In children and young adults, skeletal muscle synthesis is regulated by insulin secretion and caloric intake. However, in older adults, this switches to a pathway regulated by the essential amino acid leucine. To protect themselves from age-related loss of lean muscle, it is important for older adults to eat more than 30 grams of protein at least two or three times a day.

4. Exercise, calcium supplements and vitamin D are important for the prevention of osteoporosis. However, in the elderly, it has been found that calcium supplements will not be effective against osteoporosis unless the daily protein intake is greater than 0.55 grams per pound of total body weight.

5. In type 2 diabetics, replacement of dietary carbohydrates with protein has been observed to decrease hyperglycemia, reduce post-prandial hyperinsulinemia, and improve HbA1c.


As the wise man said...getting old is definitely better than the alternative. But perhaps these recent studies have shown us that the symptoms of aging can be slowed down a bit in people who are willing to eat more protein.

Stargazey's Spouse

Yes. I'm married. I have been for 38 years. (That's not him in the picture, by the way.)

Until six years ago, both Hubby and I were significantly overweight. In 2003 I found the Atkins diet and slowly, gradually, I managed to lose 70 pounds and keep them from coming back.

Hubby paid attention the whole time. He didn't object, but he didn't want to participate either. Besides being overweight, he had type II diabetes and was taking 50 units of LANTUS insulin plus about 20 units of regular insulin every day. His blood sugars were over 180 in the morning and 300-400 in the evening. He had retinal edema and microaneurysms that were requiring more and more frequent laser treatments.

Hubby had high blood pressure, too. Even though he was on eight medications, he would sometimes have to go to the emergency room with pressures of 250/130 or higher.

Then a miracle happened. I started this blog and began discussing with him the articles I was finding about low-carb dieting and metabolic syndrome. Hubby has scientific training, and I printed out some of the relevant articles for him. Both of us began to realize that low-carb eating is not only good for weight loss, but it also causes a significant decline in blood pressure and in the symptoms of type II diabetes as well. (Read the article at the link for more specifics and even more links.)

On August 8, 2008, Hubby began the low-carb lifestyle. He didn't do Atkins induction, and he didn't keep his carbs extremely low, but he did manage to stay well below 100 carbs per day most of the time.

Since then, over eight months have passed. Hubby has never, ever stayed on a diet this long. Here are Hubby's current results.

Hubby has dropped eight pant sizes. He has has lost enough weight that he hasn't had a flare-up of his chronic back pain during the past six months.

Hubby now takes 40 units of LANTUS a day and seldom has to supplement it with regular insulin. He has decreased his Metformin from 1000mg to 500mg twice a day. His blood sugars are 80-100 in the morning and about 180 in the evening. His retinal deterioration is progessing, but it is happening much more slowly than before.

Hubby still takes eight blood pressure medications, but they are now working to keep his blood pressure at about 140/70. He has cut his clonidine in half. His ankles no longer swell in the evenings, and he only needs his pressure stockings for airplane trips.

(For those who are interested, the improvements in blood sugar control happened almost immediately, but the improvements in blood pressure were much more gradual.)

Granted, Hubby's experiences do not constitute a scientific study. But they do bear out the fact that the findings of scientific studies can be experienced by real people in the real world. Low-carbing is not a magic bullet. However, for people suffering from the symptoms of metabolic syndrome, including overweight, insulin resistance and high blood pressure, the low-carb lifestyle is definitely worth serious consideration.

Early Insulin Resistance Predicts Subsequent Risk of Metabolic Syndrome

Insulin resistance and metabolic syndrome are most often thought of in connection with middle age. However, an article in the March 2009 issue of the journal Metabolism shows that these conditions get their start early in life.

A biracial group of 475 girls was studied first at ages 9-10 years and then at ages 18-19 years. In the first stage of the study, the invesigators determined the body mass index (BMI) of each girl. They also determined a score called the HOMA-IR, or homeostatis model assessment of insulin resistance. Insulin resistance can be measured using an oral glucose tolerance test (OGTT), but this requires several hours and numerous blood draws. In the HOMA-IR, the fasting levels of insulin and glucose are determined, multiplied, and converted into a score that correlates well with the insulin resistance determined by more technically-demanding methods. The girls were divided in two ways: (1) according to whether their BMI put them in the bottom, middle or top third of the group with regard to to relative obesity (2) according to whether their HOMA-IR score put them in the bottom, middle or top third with regard to relative insulin resistance.

Nine years later the girls were assessed for five metabolic syndrome risk factors. These included:

• Triglycerides
• High-density lipoprotein cholesterol
• Systolic/diastolic blood pressure
• Waist circumference
• Blood glucose

Each risk factor measurement was converted to a z score, which is a way of expressing the relationship of a specific measurement to the population average and the standard deviation of that particular variable. The five z scores were added for each individual. If the total z score was negative, that meant that the individual had a lower risk of metabolic syndrome. (The more negative the total, the better in this instance.) If the total z score was positive, that meant that the individual had a higher risk of metabolic syndrome.

The results were not surprising. The girls who had the lowest BMI and the lowest insulin resistance at ages 9-10 were found to have the lowest risk of metabolic syndrome at ages 18-19. As initial BMI and insulin resistance scores rose, the subsequent scores for risk of metabolic syndrome also rose. The girls who had the highest BMI and the highest insulin resistance at ages 9-10 had the highest risk of metabolic syndrome at ages 18-19. It appears that childhood obesity and insulin resistance interact to produce a higher risk of metabolic syndrome in early adulthood.

Taking it one step farther, the significance of metabolic syndrome in childhood was underlined by a study recently published in the journal Pediatrics, Metabolic Syndrome in Childhood Predicts Adult Cardiovascular Disease 25 Years Later. In this study, the investigators found that the incidence of cardiovascular disease for their 31 patients with pediatric metabolic syndrome was 19.4%, while the incidence was 1.5% for the subjects without metabolic syndrome as children. If these findings are correct, children with metabolic syndrome are significantly more likely than their peers to experience cardiovascular disease twenty five years later as adults.

The obvious question becomes, what happens to these children if intervention takes place between their pre-teen years and their forties? And what would that intervention be? Would it be pharmacological? Would it involve a change in dietary habits? There is a bias at this blog for at least trying a low-carb eating strategy to lower BMI, reduce insulin resistance, avert childhood metabolic syndrome and prevent the progression to adult cardiovascular disease. Whether or not that approach will be tested in the scientific community remains to be seen.