Recent data indicates there are several signs that can tell you if a person is having a problem with Leptin levels. These include: Leptin is a product of the obese gene. It is a protein hormone that affects the regulation of body weight and metabolism. Leptin is produced by fat tissue and is secreted into the bloodstream where it travels to the brain and other tissues. Leptin causes fat loss and decreased appetite and plays a very important role in calorie intake and calorie burning.

*Uncontrollable cravings, especially sugar

*Late night eating

*Stress eating

*Weight gain around the middle

*Inability to reach a goal weight

*Yo-yo dieting

*Low thyroid symptoms

There have been years of studies done on Leptin and they have all had very interesting results. Studies have shown that while receiving Leptin, subjects ate less and had an increase in their energy use. Many researches feel that Leptin gives new clues to why weight control is so difficult for some people.

They report that Leptin helps people to lose stored fat and that regular dieting generally robs the body of both fat and muscle. When peple diet, the body compensates for reduced calorie and fat intake by lowering your energy and metabolism. Research indicates that Leptin can actually increase energy and metabolism. Just like everything else, some people are more susceptible to having problems with their natural Leptin levels than others. Many people who try to lose weight can find it difficult, even if they eat smaller portions and exercise. Studies indicate this can be due to Leptin levels and regulating these levels may end their battle with the scale. But for some it is not that simple, researchers say that Leptin will not help everyone lose large amounts of weight. For some people it's just simply poor nutrition and lack of exercise. The best diet and exercise plan in the world won’t work unless the Leptin levels are correct. People who have constant problems controlling weight, in that they lose and gain, only to remain basically the same size - or show some of the symptoms listed above, may have a problems with Leptin levels.

The effects of leptin were observed by studying mutant obese mice that arose at random within a mouse colony at the Jackson Laboratory in 1950. These mice were massively obese and hyperphagic. Leptin itself was discovered in 1994 by Jeffrey M. Friedman and colleagues at the Rockefeller University through the study of those mutant mice. The Ob(Lep) gene (Ob for obese and Lep for leptin) is located on Chromosome 7 in humans. Leptin is produced by adipose tissue and interacts with six types of receptor (LepRa–LepRf). LepRb is the only receptor isoform that contains active intracellular signaling domains. This receptor is present in a number of hypothalamic nuclei where it exerts its effects. Importantly leptin binds to the Ventral Medial nucleus of the hypothalamus known as the "satiety center." Binding of leptin to this nucleus signals to the brain that the body has had enough to eat -- a sensation of satiety. A very small group of humans mostly arising from inbred populations are also mutant for the leptin gene. These people eat nearly constantly and may be more than 100 pounds (45 kg) overweight by the age of 7.

Thus circulating leptin levels give the brain a reading of energy storage for the purposes of regulating appetite and metabolism. Leptin works by inhibiting the activity of neurons that contain neuropeptide Y (NPY) and agouti-related peptide (AgRP) and by increasing the activity of neurons expressing a-melancyte-stimulating hormone (α-MSH). The NPY neurons are a key element in the regulation of appetite; small doses of NPY injected into the brains of experimental animals stimulates feeding while selective destruction of the NPY neurons in mice causes them to become anorexic. Conversely α-MSH is an important mediator of satiety and differences in the gene for the receptor at which α-MSH acts in the brain are linked to obesity in humans.