What is leptin?
Leptin is one of the key hormones that regulate both hunger and energy metabolism in the human body. Since fat is the site for the synthesis of this hormone, thanks to the leptin, the brain receives information about what is the mass of the body and how much energy is stored in the adipose tissue( 1).
It is believed that obesity is testically associated with a violation of the leptin metabolism in the body. The brain as if ceases to "see" excess fat, starting to believe that it is on the verge of starvation, resulting in a sharp increase in appetite. However, most diets only aggravate the situation.
The principle of the action of leptin
In the body of a healthy person, leptin is the key regulator of appetite. Since this hormone is produced in fat cells, the more their number, the higher the level of leptin in the body. In fact, the normal level of the hormone tells the brain that there is enough energy.
Decreasing leptin becomes a dangerous signal that the energy is coming to an end. To protect the processes of life support, the brain has no choice but to include the mechanism of "severe hunger" in order to send a person to search for food as soon as possible.
Leptin and obesity
Theoretically, a high level of leptin should inform the body that fat cells contain a significant amount of energy - however, with obesity, the mechanism fails. The brain ceases to notice this hormone and begins to erroneously believe that a person needs extra calories.
The result is the emergence of a "wolf" sense of hunger and a desire to eat everything that is in sight. Unfortunately, the mechanism works in a closed circle - the more fat the body gains, the worse the brain "sees" this fat, and the more it forces the person to seek food( 2).
Why do you want to eat on a diet?
If an obese person begins to follow a diet with a significant restriction of calories, then about 2-4 days, the level of leptin drops sharply. However, the brain, as before, is not able to understand that the reserves of subcutaneous and internal fat are enough - and, again, includes a sharp feeling of hunger.
The situation is aggravated by the fact that in parallel with this the body passes into the "energy conservation regime" - the metabolic processes( including the synthesis of sex hormones) are slowed down as much as possible, the working capacity decreases and drowsiness appears. The result is a terrible state of health and a wild appetite.
Leptin in slimming tablets
Because most people do not understand the physiology of their body very well, they only know that leptin is a hormone of hunger, and the higher its level, the less you want to eat. From these facts they make a controversial conclusion that leptin in tablets reduces appetite and helps to lose weight.
However, this is not the case. As we mentioned above, in obese people and so high level of leptin in the blood - an additional increase in the level of this hormone will not change the situation for the better. The only way to lose weight is to follow a diet to normalize the level of leptin.
Why is it harder for women to lose weight?
In most cases, in women, the normal level of leptin is 2-4 times higher than that of men( 3).That's why women are more often in the "leptin trap", trying to lose weight by refusing to eat. Trying to overcome themselves and suppress the feeling of hunger, they even more break the metabolism.
Among other things, a higher base level of leptin also explains that men lose weight faster by dieting, and women - due to active physical training. However, unfortunately, in reality, diets are most often considered a "female theme", and training - a male.
Diet for normalization of leptin level
Regular intake of large doses of simple carbohydrates( sweets, baked goods, bread, potatoes) is a key factor that breaks normal metabolism( 2).The brain gets used to the chronically high level of glucose in the blood, reducing both the sensitivity to insulin and leptin.
To return the body's ability to respond adequately to leptin( and insulin), it will take almost complete refusal of fast carbohydrates - however without a sharp restriction of caloric intake. The most simple diet in this case will be a protein( or non-carbohydrate) diet.
Hormone leptin is the key regulator of appetite and satiety, as it is this hormone that informs the body about the presence of fat stores. In this case, obesity is almost always associated with a violation of the ability of the brain to respond adequately to high levels of leptin.
- Positional cloning of the mouse obese gene and its human homologue, source
- Serum immunoreactive-leptin concentrations in normal-weight and obese humans, source
- Gender differences in serum leptin levels in humans, source