Obesity, as most people think, is caused so simply like by overeating or due to lack of physical activities. Though they contribute greatly to the disease but obesity has a lot more to do with hormones. Even the scientists agree to the fact that obesity is a complex disorder and its causes are not fixed.
Leptin and insulin are the two hormones produced inside our body which is responsible for excessive weight gain or obesity. Let's understand how the two hormones affect our body, one by one.
Leptin is produced by the fat cells in the body. It sends signals to the part of the brain that is responsible for controlling our food intake (hypothalamus) that our stomach is full and we don't need to eat any longer. Some people are resistant to leptin so they cannot interfere if they are full or not and they eat a lot more than required. This is because the brain does not receive any signal from leptin and so it feels that we are still hungry. Leptin tells the brain that we have sufficient energy.
If you are thinking that obese people lack leptin then you are wrong. Obese people have a lot of fat cells and these cells produce leptin. Therefore, obese people have a lot of leptin too. So where does the problem arise? The problem is that the leptin is not able to signal the brain. In simple words, the brain cannot see leptin in fat people. Leptin is unable to inform the brain about the abundance of energy and fat and therefore it thinks that we are starving. Such a condition is known as leptin resistance. It is known to be the leading cause of obesity in most of the people. People suffering from such a condition face a lot of difficulty in reducing weight.
Scientist Lustig, along with many other reputed scientists, believes Insulin to be the major culprit of obesity.
Insulin is one of the most important hormones in our body. It performs various functions like picking up glucose from the bloodstream. Regulating energy storage is one among the many functions. One of the important functions of insulin is to inform the fat cells to store fat (energy in the form of fat or glycogen) and also to hold on to the already present fat in them.
Many people are becoming insulin resistant because of the Western diet.This causes an elevation in the insulin levels all over the body. It makes the energy get stored, selectively, in the fat cells instead of being present and available for utilization.
Lowering of insulin can be done by the cutting on carbohydrates which will in turn result in an automatic decrease in the intake of calories and offer an effortless weight loss. You won't need to cut down a lot of food or keep a regular check on your calories every time before you sit to eat your meal.
Dr. Lustig also stated that insulin is responsible for blocking the signals of leptin to the brain. This is why having chronically elevated insulin levels can make people leptin resistant.
High Level of Insulin= blocking of leptin signals= brain's inability to see that the amount of energy taken is substantial= a lot of food intake= obesity.
So we see that both the hormones affect each other's behavior which, in turn, affects our health and well-being. A good diet and lifestyle will prevent such an imbalance in these hormones. You don't need to hit the gym as soon as you begin to gain weight, rather, find out the main reason for your weight gain, follow a proper diet (you can also take the help of certain fitness shakes present in the market), and believe in yourself.