Do you rebound after dieting? Scientists can help you prevent it!

When it comes to dieting to lose weight, are you full of complaints? You work hard on a diet, only to gain the weight back easily. It can be said that for every success you have had on a diet, there have been as many failures of gaining the weight back. You may even become fatter than before the diet.

Why can't you get rid of fat? Why do you always get hurt? What is the underlying mechanism behind this? Recently, researchers from the Max Planck Institute for Metabolism and Harvard Medical School published a research paper in Cell Metabolism, which gave the answer. What's more exciting is that they also found a corresponding solution.

Five conclusions from the study:

① Weight loss after caloric deprivation activates paraventricular hypothalamic thyrotropin-releasing (PVHTRH) neurons, which co-express pituitary adenylate cyclase-activating polypeptide and increase the number of synapses between PVHTRH and the "hunger" neuron AgRP;

② The enhancement of excitatory synapses leads to a long-term increase in food intake, which lasts until weight is restored;

③ Suppressing PVHTRH neurons will inhibit the enhanced excitatory input of AgRP neurons and reduce the accompanying weight rebound;

④ Brief stimulation of this pathway can permanently enhance this glutamatergic hunger synapse, causing sustained ionotropic glutamatergic receptor-dependent weight gain;

⑤PVHTRH neurons may become a target for combating weight rebound.

Simply put, the study found through a series of experimental methods that when you are dieting, your body will activate the PVHTRH neurons in the hypothalamus due to lack of calories. Then your neuronal synapses will trigger the brain to send stronger hunger signals, causing you to eat more and crave some "high-calorie" foods more.

This is why you are more likely to have the physiological urge to overeat after dieting. So, you really don’t need to blame yourself. It’s not because you are not self-disciplined. This is the normal feedback mechanism of the brain and an instinct engraved in your DNA.

Image source: pixabay

Based on the above findings, the researchers silenced the PVHTRH or DMHVglut2 neurons of mice during fasting. The results showed that after inhibiting PVHTRH neurons, the increase in food intake in mice was greatly reduced 8 hours and 24 hours after resuming diet after fasting, compared with the control group!

At the same time, in the following days, the mice's weight rebound was also reduced. This shows that the activity of PVHTRH neurons is very important for the mechanism of weight rebound. However, DMHVglut2 neurons have no obvious effect on food intake and weight rebound.

Although the dieting model is not suitable for everyone, this study provides a possibility that in the future, therapy that inhibits signals from PVH neurons may help people maintain their weight loss results.

Of course, more research is needed to understand the functions of PVH neurons and the consequences of silencing them.

In fact, every scientific progress is based on the accumulation of such trickles, through continuous trial and error from observation and experiment, and eventually phased results are achieved. The essence of science is to explore the unknown and solve problems. Let us maintain critical thinking and promote scientific progress together.

Main references:

1.Grzelka K, Wilhelms H, Dodt S, et al. A synaptic amplifier of hunger for regaining body weight in the hypothalamus. Cell Metab. 2023 Mar 16:S1550-4131(23)00080-3.

The article is produced by Science Popularization China-Starry Sky Project (Creation and Cultivation). Please indicate the source when reprinting.

Author: Shanxi Medical University Health Science Communication Team

Reviewer: Tao Ning, Associate Researcher, Institute of Biophysics, Chinese Academy of Sciences