Many people who have dieted are familiar with the yo-yo effect: after the diet, the kilos are quickly put back on. Researchers 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.