Dieting: Brain amplifies signal of hunger synapses

Many people who have dieted are familiar with the yo-yo effect: after the diet, the kilos are quickly put back on. Researchers from the Max Planck Institute for Metabolism Research and Harvard Medical School have now shown in mice that communication in the brain changes during a diet.

The nerve cells that mediate the feeling of hunger receive stronger signals, so that the mice eat significantly more after the diet and gain weight more quickly. In the long term, these findings could help developing drugs to prevent this amplification and help to maintain a reduced body weight after dieting.

The researchers put mice on a diet and assessed which circuits in the brain changed. In particular, they examined a group of neurons in the hypothalamus, the AgRP neurons, which are known to control the feeling of hunger. They were able to show that the neuronal pathways that stimulate AgRP neurons sent increased signals when the mice were on a diet. This profound change in the brain could be detected for a long time after the diet.

The researchers also succeeded in selectively inhibiting the neural pathways in mice that activate AgRP neurons. This led to significantly less weight gain after the diet. "This could give us the opportunity to diminish the yo-yo effect," said the researchers.

In this present study, they found that the physical neurotransmitter connection between these two neurons, in a process called synaptic plasticity, greatly increases with dieting and weight loss, and this leads to long-lasting excessive hunger”,

Reference:

Dieting: brain amplifies signal of hunger synapses; Cell Metabolism