Stress turns off the brain’s natural response to satiety, which stops eating, and thus, encourages continued eating to be rewarded, according to a new study that may explain why we crave high-calorie ‘comfort foods’ when we’re chronically stressed. Research has shown that this occurs in the brain’s lateral habenula, which when activated normally dampens reward signals and thus stops eating when a person is satiated or full.
“Our findings reveal that stress can override a normal brain response that reduces the pleasure gained from eating meaning the brain is constantly rewarded for eating,” said Herbert Herzog, senior author of the study and visiting scientist at the Garvan Institute of Medical Research in Sydney, Australia.
The researchers also said that their study showed how chronic stress can promote weight gain and obesity, and thus, highlights the need for a healthy diet in times of stress. Their work is published in the journal Neuron.
Some people seem to eat less during times of stress, while others eat more than usual and choose high-calorie options high in sugar and fat. Seeking to understand the varied eating behavior of humans in response to stress, researchers have studied mouse models to determine how different brain regions respond to chronic stress under different types of diet.
“We discovered that the lateral habenula was activated in rats fed a short-term, high-fat diet to prevent the animal from overeating. However, when the rats were chronically stressed, this part of the brain remained silent allowing the reward signals to remain.
Active and happy. encourage feeding, no longer responding to satiety regulatory signals,” explained first author Kenny Chee Kin IP of the Garvan Institute.
“We found that mice stressed on a high-fat diet gained twice as much weight as mice on the same diet that weren’t stressed,” said Ip.
At the heart of the weight gain was the molecule NPY, which is naturally produced by the brain in response to stress, the researchers found when they blocked NPY from activating brain cells in the lateral habenula of rats fed a high-fat diet.
Thus, the mice consume less comfort food, resulting in less weight. The researchers also found in mice that those stressed on a high-fat diet consumed three times more sucralose (here artificially sweetened water) than those fed a high-fat diet alone, suggesting that stress increases cravings for sweet, palatable foods. Food.
“Importantly, we did not see this preference for sweet water in stressed rats on a regular diet,” said Herzog. “In stressful situations, it’s easy to use up a lot of energy and the feeling of reward can calm you down this is when boosting energy through food comes into play.
“But when experienced over a long period of time, stress seems to change the equation, driving long-term eating habits that are bad for the body.” This research emphasizes just how much stress can compromise healthy energy metabolism.
“It’s a reminder to avoid a stressful lifestyle, and importantly, if you’re dealing with chronic stress, try to eat a healthy diet and cut out junk food,” Herzog says.
