Friday, January 2, 2009

But you have to eat carbohydrates!

Perhaps you overdid it a bit at Christmas and are looking for a weight-loss plan. Although low-carb diets are currently out of fashion, they have one big advantage over low-calorie, low-fat diets. They work.

Ordinary people can lose weight and keep it off by following a low-carb eating plan. Not only that, they will notice an improvement in blood pressure, HDL cholesterol, triglycerides, and insulin responsiveness. So why don't more people attempt weight loss through the low-carb lifestyle?

One big reason is that people are told (incorrectly) that their body requires them to eat a certain amount of carbohydrate every day. The brain requires glucose to function, and several other tissues require carbohydrate-derived fuels as well. If a person doesn't eat any carbohydrates, where does this fuel come from?

It comes from proteins. After proteins are eaten, they are broken down into their building blocks, which are called amino acids. These amino acids can be reassembled into other proteins. Some of them can be converted into fat. And thanks to a metabolic process called gluconeogenesis, up to 400 grams of them per day can be converted into carbohydrates.

Since the brain requires only about 120 grams of carbohydrates a day, that's well within a safe range. It does take a few days for the enzymes of gluconeogenesis to be induced, permitting conversion of enough glycogenic amino acids into glucose to supply the tissues that require it. During the transitional period, typical symptoms may include body aches, nausea and headaches. These will subside after about three days, and energy levels and alertness will improve noticeably. To figure out how much protein to eat to permit adequate carbohydrate synthesis, Jenny Ruhl has provided this convenient Protein Need Calculator.

If you need to start a weight-loss plan, there are many good diets available, including many versions of low-carb diets. Check out your options and pick the diet that suits you the best. And if you choose the low-carb lifestyle, be assured that thanks to gluconeogenesis, you can safely drop most or even all of the carbohydrates from your menus!

1 comment:

Anonymous said...

From what I remember your brain can also run on ketones. Nice post!