A variety of factors control hunger, fullness and appetite, all of which ultimately controls our weight and body fat. This includes everything from sleep, to stress and exercise. Hormones are also involved in this complex process, particularly the two that are often referred to as hunger hormones, Leptin and Ghrelin.
Leptin and Ghrelin are opposing hormones. Leptin is the satiety hormone. It tells you when to stop eating. It makes you feel full and it blocks appetite. Ghrelin, on the other hand, tells you when you’re hungry and need to eat. It’s made in the stomach primarily and it’s released when you haven’t eaten for a while. When one is rising, the other is falling so, in a perfect world, if everything is in balance they cancel each other out so to speak and nobody should have problems with gaining body fat or overeating. Unfortunately, the world is not perfect.
Leptin levels fluctuate with how much fat you have. When you lose weight, Leptin levels drop. With less of that appetite-suppressing hormone, hunger levels go up and you will likely start to eat more, which, as you can guess, causes you to gain back the weight you lost, and probably even more, before Leptin levels return to normal.
If you are a chronic overeater you can also develop an insensitivity to Leptin. If you have normal Leptin sensitivity, you lose the desire to keep eating when you’re satisfied. When you are Leptin insensitive, this switch does not flip and you continue to eat well beyond what your body requires.
Ghrelin levels also vary with weight loss. After dieting, Ghrelin production increases which increases hunger. Increased hunger has the obvious side effect of causing people to eat more and gain weight. When Ghrelin levels are elevated, cravings can become almost uncontrollable.
It is not hard to see why low Leptin levels combined with high Ghrelin levels is not a good situation. Increased appetite and uncontrollable craving have never been helpful when trying to cut body fat. So, what do you do to avoid this situation?
Humans have evolved to fight starvation. That is why these are activated when we lose weight. They literally are fighting against us starving to death, even when we are very far from it. This seems to happen after about a 5%-7% loss in body weight give or take a percent or two. This explains why a 200lb person can lose 10-15lbs quite easily. It is the next 10-15 pounds that trips them up as the Leptin drops and Ghrelin rises. This change in hormones causes them to eat more and gain back everything they have lost.
Although not a solution, it can be helpful to drop about 5% of your body weight and then eat at baseline for a while before reintroducing a deficit (eat to maintain your current weight before reducing the amount again to lose more weight). You may gain a few pounds back in this time, but when you begin to drop again you will be able to drop a bit more body fat than before. Think of it as 3 steps forward and 1 step back. It won’t be fast but real progress never is. Losing weight at a fast rate basically guarantees regaining it just as fast.
Another helpful strategy, and probably the most important one, is do not just create your calorie deficit with calorie restriction only. It is true you cannot usually out exercise a poor diet, but exercise, both weight training and cardio work, should be part of your fat loss plan. Muscle mass will help keep your metabolic rate up, so you want to at least maintain the muscle you have. That is where weight training comes in. Exercise may also help keep Leptin from dropping too much and Ghrelin from elevating to high.
It is not news to anybody that has tried, losing bodyfat and keeping it off is no easy task and there is no quick fix. By combining reasonable diet, exercise including weights and cardio, and a longer-term approach, you can have success. If it was fast and easy, this article would be about the muscular and lean body epidemic sweeping the country.