Leptin is our fullness hormone. It is produced by our fat cells to communicate to the body that we have adequate energy stored. Ideally, as we store more fat in the body, leptin levels increase, and we feel full from smaller portions of food. Unfortunately, decreased leptin sensitivity in obesity means that although leptin levels are high, the target cells resist the impact of leptin. This means we don’t get the increased feelings of fullness, and can continue to gain weight. Studies have found that avoiding high glycemic foods is important to improving leptin sensitivity.
Leptin levels decrease naturally when we lose fat. This makes it harder to maintain weight loss because it takes bigger portions of food to feel full. One very new area of research is studying administering leptin to patients who have already lost weight. Early findings indicate this could be an effective way to prevent regain after weight loss.(1)