Losing weight may be easy, but maintaining it is difficult. But scientists (so we) now have better understanding of long term weight maintenance.
A person may lose as much as more than 200 kg of weight in 15 to 20 years and gain more than 200 kg. How it is possible and why it happens? It is possible by losing weight and again gaining the lost weight. Why it happens is because the human body is designed to sabotage weight loss at every turn. Once a body is fatter, it wants to revert to what it used to be. Physiology gets changed in two ways, the body needs fewer calories to maintain itself but the craving of food becomes more intense. So, keeping the food away means pitting oneâ€™s willpower against several biological processes involving brain, metabolism, hormones, and fat storage. That is why most people can lose weight but only few can sustain it.
Human body is designed to protect against weight lose and starvation. After a period of obesity human body change permanently the way weight is regulated by stimulating the appetite more and protecting the fat stores. After the permanent change the metabolism also changes permanently. The body requires eight (8) calories per day less energy for every pound of weight lose. This difference in energy need before and after weight loss is called “energy gap”.
There are hormonal changes also. Appetite hormone leptin, for example, is appetite regulator. This leptin tells the body to stop eating and store fat after meal. But after weight loss leptin levels are lower than before weight lose. That means appetite is more difficult to suppress. Some people are genetically prone to have lower leptin level and prone to weight gain and obesity. Similarly, another hormone ghrelin, stimulate food intake. Its level in brain falls after meals. But after weight lose the levels of ghrelin increases, and fall after meal is not as marked.
If you lose 10% of your body’s weight all the above mechanisms come into play and try to keep you from losing weight. That is the reason losing 10% of body’s weight is very easy and it becomes very difficult after that. So the person who gains weight after losing it not directly responsible for his weight gain again, it is the biology which is responsible.
There have been some interesting facts about the people who could maintain weight after losing it. They follow certain things like, instead of trying to eat less lifelong to bridge the energy gap, these people exercise more. Exercise influences some biological systems that promote weight regain, encourage the body to be more sensitive to leptons and insulin. These persons also change what they eat. They keep their calories in careful balance with what they expend. They tend to eat low fat foods.
Scientists are trying to find out how to turn the physiological response in our favor and the day is not very far when we will be able to eat and not gain weight. If not what we want to eat, at least we can eat hearts content of food (may not be of our very liking) and not gain weight.