Leptin, we touched briefly on Tuesday, but I felt it was worthy of a little more attention. Like I metioned, it is a hormone birthed by visceral and subcutaneous fat. When we eat, leptin is secreted in response to the circulatory system. Eventually, finding its way to the hypothalamus. The hypothalamus has receptors that corresponds to metabolic control, responding to the leptin. Leptin provides satiety (feelings of fullness) and increases energy expenditure (especially stored body fat). There are two aspects: fasting. During times of fasting or calories restriction, leptin sensitivity is lowered, causing greater hunger, cravings, and lack of energy. Cells can also become resistant to leptin. This results in a skewed appetite, sucky energy levels, and of course fat gain. Over a longer period this puts on e at risk for metabolic conditions like diabetes and heart disease. so too few calories can lead to cravings, as can over consumption and leptin resistance. Also in accordance with extra poundage being a hinderance, circulating levels are proportional to body fat percentage. So agin, heavier people= more cravings. Other things leptin does:
- work with hypothalmic neurons that secrete gonadotropin-releasing hormone (which is why women with low-fat may stop having periods because of a lack of leptin-secreting fat cells) and stimulates sympathetic nervous system (important formation and breakdown of bone).
- Acts on liver and skeletal muscle to decrease storage of fat
- Acts on T-cells to enhance Th1 cells
- May play a role in the hippocampus, which is critical to memory, and therefore, age-related cognitive decline
Of course there are other factors besides food intake. SLEEP, does it again. Less sleep=less leptin. Also, melatonin (associated with sleep) can heal leptin receptors and restore leptin sensitivity (which is good news for weight-loss). Now sleeping enough= not enough melatonin= no restoration to normal leptin levels. Also, consuming too much fructose, causes insulin resistance. How to keep normal leptin levels and keep that metabolism churning? cycle proteins and fats; avoid grains, starches and sugars; and GO TO BED. For more on our fat-burner weight-loss programs check out our website at bodychange.net.