Leptin and Weight Loss Resistance

Unfortunately, our bodies are designed by nature to resist weight loss at all costs. Experienced dieters know this phenomenon very well - you go on a diet and, initially, feel absolutely euphoric - pounds melt quickly and your body feels great! However, in a month or so, you notice that weight loss has stopped and you have reached a plateau stage, although you continue exercising and depriving yourself from extra-calories and tasty foods.

In a while, oh horror, all your lost pounds slowly cripple back despite dieting, sweating in the gym, and even popping down weight loss supplements! At the end, disillusioned dieters give up both the diet and their newly obtained “healthy lifestyle”, and usually gain about 5 pounds on top of what they had before… A fair question is what physiological mechanisms are hidden behind these typical plateau and yo-yo effects of dieting? And how can we overcome them?

It seems that researchers have finally found the answer to the riddle why our bodies tend to resist ongoing weight loss. A rat study conducted by scientists from New York Obesity Research Center, Cornell University, Columbia University College and the Institute of Human Nutrition may hold the key to the understanding why human organisms are programmed to gain weight instead of losing it. The study results, offering the explanation and possible hints on how to overcome the plateau effect, have recently been published in the medical journal Metabolism.

The researchers’ idea is that humans (just like rats) are born with physiological mechanisms that protect them from losing too much weight, even when they are obese. This is why dieting, running, taking weight loss supplements, and even applying to surgical interventions, e.g. gastric bypass, are often not effective. The study has found that the loss of some weight, which usually happens during the first weeks of dieting, reduces the body amount of leptin - a specific hormone that is secreted by adipose (fat) cells. Since the obese body is accustomed to certain (read high) levels of leptin, the brain assesses the situation as starvation and turns on specific protective mechanisms: metabolism slows down; appetite climbs up; levels of “feel-good” hormones, such as dopamine and serotonin, fall down; and the dieter starts suffering from mood swings, apathy, irresistible food cravings, and even depression. This vicious circle is almost impossible to overcome even for the most devoted dieters.

Previous research made scientists believe that overweight rats, as well as overweight humans, had elevated levels of leptin in their bodies. However, adding leptin in a pill form to the ration of experimental animals did not promote their weight loss - the rats were still hit by the plateau effect. The present study has shown that a mixture of Meridia, a weight-loss medication, with dietary leptin may be effective in overcoming this weight-protective mechanism. The researchers fed the mixture to obese rats and noticed that they started rapidly losing their fat deposits without experiencing that seemingly inevitable plateau phenomenon.

Obesity is becoming an increasingly serious problem everywhere in the world, and especially in the developed countries, including the US. Excess weight is an additional risk factor in developing such serious diseases as type 2 diabetes, certain cancers, gallbladder stones, and cardiovascular disease. This is why it is so important for scientists to invent a safe, practical, and effective medication that will help big people shed off their unhealthy poundage. Hopefully, this new finding of the American researchers will become a revolutionary discovery leading to developing new, leptin-based drugs to treat overweight and obesity.

Human studies are already planned to find out if the weight-loss effect of both Meridia and leptin can be effective in people at the same degree as in rats.

Kim Suffolk