Leptin is a hormone produced by fat tissue in the body. It regulates appetite and weight loss and plays a role in the regulation of blood circulation, blood clotting, the creation of new bone, and the maintenance of body temperature. It also has an effect on female reproduction, immune functions, and the function of many other hormones, including insulin. It was initially discovered in 1994 by Jeffrey Friedman and his team at Rockefeller University.
Leptin binds to receptors in the hypothalamus, which then release chemicals that signal the body to stop eating. Giving this hormone to patients who are deficient in it will result in a weight loss. However, obese patients receiving the hormone do not benefit from the same weight loss effect.
Researchers hypothesize that the lack of weight loss in obese individuals is caused by chronically high levels of circulating leptin. In fact, the greater the amount of fat tissue, the higher the level of the circulating hormone.
Because the obese person’s fat cells are constantly being bathed in leptin, the cells become resistant to its “stop eating” message. This mechanism is similar to Syndrome X, in which the body becomes resistant to chronically high levels of insulin, which if not addressed, could eventually result in a diagnosis of diabetes.
According to Rockefeller University, leptin therapy has been shown to be an effective therapy for a number of other human conditions associated with low levels of this hormone, including several different forms of human diabetes and a condition known as hypothalamic amenorrhea.
This condition, which develops in extremely thin women — often ballet dancers or long-distance runners — is one of the most common causes of infertility in women, and treatment with this hormone has been shown to restore reproductive function in these patients.
Factors in Weight Loss
Ron Rosedale, M.D. has written a book called The Rosedale Diet in which he prescribes an eating plan for overcoming leptin resistance. His diet is basically a low carb, high fat, moderate protein diet, with an emphasis on monounsaturated fats over saturated fats.
In the first 3 weeks of the diet, he limits food choices to seafood, poultry and green vegetables. After this period, patients can add more meat and lower-fat dairy products. He also recommends that patients eat smaller meals more often, and to eat foods containing fat if you are hungry. (He recommends using nuts as snacks).
I have reservations about Rosedale’s book because he advises patients to avoid saturated fat. There is little reason to avoid saturated fat while on a low carb diet.
Jan Kwasnieski, a doctor in Poland has used a ketogenic diet (which is high in saturated fat), to reverse obesity and diabetes in many patients. Other studies done on ketogenic diets have also improved health factors. See Jeff Volek’s work at the University of Connecticut.
Resources for Further Reading
- HHMI: Jeffrey Friedman’s Bio
- Rockefeller University webpage on Jeffrey Friedman
- Science Daily Article: Battle of the Bulge
- The Rosedale Diet by Ron Rosedale, MD.