Monday, May 30, 2011
Vacation // Can Leptin Keep You Light?
On May 31 hubby and I leave for a 14-day vacation in Northern Europe. I will have limited access to the internet, so go ahead and leave comments if you wish, but they may end up in comment limbo for a fairly long time. I probably won't be able to respond to questions very well, and you may have to wait until I return to get a detailed answer.
While I'm gone, I'll give you something to think about. During the last few days I've been having fun over at Stephan Guyenet's Whole Health Source blog. Commenters have been discussing his post on Food Reward: a Dominant Factor in Obesity, Part IV and have started thinking about the effect of leptin on the prevention of weight regain following a significant weight loss. Commenter ItsTheWooo2 has lost over 160 pounds but is now faced with the lifelong challenge of maintaining that weight loss. She noticed that when she began taking injectable synthetic leptin as an experimental treatment for hypothalamic amenorrhea, the leptin made it much easier for her to stay at her goal weight. Wooo has some rather strong opinions, but she also explains herself well, and the comments are worth reading if you have the time.
During the discussion, Stephan mentioned the work of Rudolph L. Leibel at Columbia University. Conveniently, one of the commenters gave a link to a blogpost summarizing Dr. Leibel's work on lepin, Why is it so Hard to Maintain a Reduced Body Weight? The blogger, Arya M. Sharma, M.D., has a couple of followup posts entitled Why Hyperleptinemia is Not Leptin Resistance and Using Leptin to Treat Obesity.
If you would like to look at some of the primary literature on the topic, here are several articles: Low Dose Leptin Administration Reverses Effects of Sustained Weight-Reduction on Energy Expenditure and Circulating Concentrations of Thyroid Hormones
, Low-dose leptin reverses skeletal muscle, autonomic, and neuroendocrine adaptations to maintenance of reduced weight , and Leptin reverses weight loss–induced changes in regional neural activity responses to visual food stimuli .
It has been nearly ten years since the first of these studies was published. One wonders why such an efficatious drug is not being prescribed far and wide for the maintenace of weight loss. According to Dr. Sharma, this has to do with a peculiarity in the regulations of the FDA. Drugs can be licensed for weight loss, but except in extremely rare cases, leptin does not work for weight loss. However, the FDA does not recognize a need for drugs to preserve weight loss once it has happened. Leptin is a drug that works for a condition that the FDA does not believe exists. The FDA does not understand that, while weight loss is hard, weight maintenance is even harder. If you think that synthetic leptin might help you hold on to your hard-won weight loss, it might be time to send the FDA a letter.