Leptin is a complex hormone that helps regulate food intake and body weight. A part of your brain controls leptin levels in conjunction with your body fat mass. Because leptin suppresses appetite, it may seem beneficial to raise your level. It's more complex than that, however. Lower leptin levels are actually associated with a healthy body weight. So the goal is not to raise leptin but to eat foods that improve leptin sensitivity so that your body responds better to its signal.
How Leptin Regulates Energy
Scientists have yet to learn all of the mechanisms by which leptin regulates energy balance, but they do know that leptin suppresses an appetite-stimulating hormone called neuropetide Y. Leptin also boosts metabolism to help regulate body weight. The hormone is secreted from your fat cells, and levels are correlated with body fat percentage. When body fat levels fall, leptin levels decrease and appetite is stimulated; when fat mass rises, the opposite occurs. In this way leptin helps the body maintain healthy weight.
Insulin and Leptin Work Together
Insulin is a hormone that helps regulate blood sugar. Together with leptin, it regulates food intake and metabolism, according to a review that appeared in the 2004 issue of the journal Endocrinology. When you eat a carbohydrate-containing meal, your blood sugar rises, signaling your pancreas to release insulin. The presence of insulin in the bloodstream triggers pathways in the brain that signal the body to reduce food intake. According to the authors, insulin and leptin have a combined effect at suppressing appetite, and the two hormones interact in the brain to reduce food intake.
Foods That Improve Leptin Resistance
As with insulin, when levels rise and remain elevated, the body becomes less sensitive to its effects. In response, more leptin is released, leading to leptin resistance. Lower leptin and insulin levels represent better sensitivity to these hormones. A population study published in the journal Circulation in July 2002 found that a diet rich in fish is linked to lower leptin. This suggests the type of fat in your diet influences leptin levels. In addition, a diet composed of lower-carbohydrate foods is linked to lower leptin, according to a study published in the August 2003 issue of the International Journal of Obesity.
Dietary Habits That Promote Leptin Resistance
The composition of your diet may promote leptin resistance. In the Journal of Obesity study, a diet high in carbohydrates significantly increased leptin levels. Triglycerides -- the main component of animal fats and vegetable oils -- increase leptin resistance, according the a study that appeared in the May 2004 issue of the journal Diabetes. In addition, an animal study found that overeating increases leptin resistance; the results were published in the December 2001 issue of the journal Diabetes.