Weight loss: Why does it become difficult to lose weight after the age of 40? Research shows the unique connection of the brain

As we age, maintaining a healthy weight becomes quite challenging for us. Even after paying attention to eating habits and exercise, it is difficult to lose weight. Often it is linked to slow metabolism, but recent research has revealed the role of the brain.

Researchers at Nagoya University (Japan) have found that with increasing age, a specific part of the brain, the hypothalamus, affects weight. The hypothalamus controls appetite and metabolism. A protein called melanocortin-4 receptor (MC4R) is found in it, which signals the body to burn more fat than necessary.

A study done on rats
Researchers studied rats and found that the size of neurons (nerve cells) containing MC4R receptors changed as they aged. Due to this, the number of receptors was reduced, due to which weight started increasing. During the study, it was also found that the length of small hairs like cilia present on the neurons of the hypothalamus also decreases with age. These cilia are the basis of the MC4R receptor. As the age of rats increased, the length of these cilia decreased significantly.

What happened in the research?
Researchers believe that the same process occurs in humans also. Professor Kazuhiro Nakamura, the lead author of this study, says that we hope that with this discovery new methods can be found for the treatment of obesity. The study also found that diet has a direct impact on the length of cilia. In rats consuming a high-fat diet, cilia shortened rapidly, while in rats eating a low-fat diet, the length of cilia decreased to no extent. Interestingly, when these mice were fed less food for two months, their cilia became longer again. This shows that changes in diet can affect the brain's metabolism and ability to control appetite.

Leptin resistance
The study also helps in understanding leptin resistance. Leptin is a hormone that is produced by the body's fat cells and signals the brain to reduce appetite. However obese people develop leptin resistance, which increases appetite and slows down metabolism. The researchers found that the mice whose MC4R receptor cilia had shorter cilia were not affected by leptin, even when leptin was injected directly into the brain. This suggests that cilia shortening with age may lead to leptin resistance.

(PC: Freepik)