A recent study sheds light on why we tend to yearn for calorie-rich comfort food when we’re under chronic stress. Researchers discovered that stress has the ability to suppress the brain’s natural response to feeling full, leading to a continued desire for rewarding food. The brain’s lateral habenula, a region responsible for regulating reward signals, was found to be affected by stress, resulting in a persistent urge to eat even when satiated. Herbert Herzog, a senior author of the study and 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.”

The study also highlighted the correlation between chronic stress and weight gain, emphasizing the importance of maintaining a healthy diet during stressful periods. Published in the journal Neuron, the research examined different brain areas’ reactions to chronic stress under various diets using mouse models. The researchers discovered that the lateral habenula played a protective role in mice on a short-term, high-fat diet, preventing overeating. However, when the mice were subjected to chronic stress, this brain region remained inactive, allowing reward signals to persist and promoting pleasurable eating regardless of satiety signals.

Kenny Chi Kin Ip, the first author of the study, explained, “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, which is naturally produced by the brain in response to stress, as a key player in the weight gain. By blocking the activation of NPY in the lateral habenula of stressed mice on a high-fat diet, the mice consumed less comfort food and experienced reduced weight gain. Additionally, the researchers observed that stressed mice on a high-fat diet consumed three times more artificially sweetened water, suggesting that stress drives a craving for sweet and palatable foods.

Herzog emphasized the significance of the findings, stating, “In stressful situations, it’s easy to use a lot of energy, and the feeling of reward can calm you down – this is when a boost of energy through food is useful. But when experienced over long periods of time, stress appears to change the equation, driving eating habits that are detrimental to long-term health.” The study serves as a reminder to avoid a stressful lifestyle and underscores the importance of maintaining a healthy diet, especially for individuals dealing with long-term stress. Herzog concluded, “If you are dealing with long-term stress, try to eat a healthy diet and lock away the junk food.”

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