A recent study has uncovered an intriguing connection between stress, our brain’s response to feeling full, and our inclination towards high-calorie ‘Comfort Food’ when faced with chronic stress. This research provides valuable insights into the reasons behind our cravings for unhealthy treats during stressful periods and may pave the way for effective strategies in managing weight gain.
The investigation primarily focused on the lateral habenula, a region in the brain that typically suppresses reward signals, thereby signaling when we are satiated or no longer hungry. However, the study revealed that stress can disrupt this natural response, effectively disabling the brain’s ability to derive pleasure from eating and leading to a continuous desire to consume food. Senior author Herbert Herzog, a Visiting Scientist at the Garvan Institute of Medical Research in Sydney, Australia, explained, “Our findings reveal stress can override a natural brain response that diminishes the pleasure gained from eating—meaning the brain is continuously rewarded to eat.”
Furthermore, the researchers emphasized that chronic stress could contribute to weight gain and obesity, underscoring the importance of maintaining a healthy diet during stressful periods. The study’s findings were published in the journal Neuron. Although some individuals tend to eat less when stressed, others experience increased appetite and opt for calorie-dense options rich in sugar and fat.
To comprehend the diverse eating behaviors people exhibit in response to stress, the scientists utilized mouse models to investigate how different brain areas reacted to chronic stress under varying diets. The research team discovered that the lateral habenula displayed activity in mice on short-term, high-fat diets, serving as a protective mechanism against overeating. However, when the mice were exposed to chronic stress, this brain region remained inactive, allowing the reward signals to persist and promoting pleasurable feeding habits, regardless of satiety regulatory signals.
Kenny Chi Kin Ip, the first author of the study from the Garvan Institute, elaborated, “We found that stressed mice on a high-fat diet gained twice as much weight as mice on the same diet that were not stressed.” The researchers identified the molecule NPY, naturally produced by the brain in response to stress, as a key contributor to this weight gain. By blocking NPY from activating brain cells in the lateral habenula of stressed mice on a high-fat diet, the researchers observed reduced consumption of comfort food, resulting in less weight gain.
Additionally, the study demonstrated that stressed mice on a high-fat diet consumed three times more sucralose (artificially sweetened water) than those on a high-fat diet alone, indicating that stress induced a craving for sweet and palatable food. Herzog stated, “A surge of energy from food is important in stressful situations, where it’s easy to burn a lot of energy and the feeling of reward can calm you down. However, stress that is felt over an extended length of time seems to alter the situation and encourage unhealthy eating.
This research serves as a poignant reminder of how stress can compromise a healthy energy metabolism and emphasizes the importance of avoiding a stressful lifestyle. For individuals facing long-term stress, the findings underscore the significance of maintaining a nutritious diet and resisting the temptation of unhealthy junk food.