Researchers Uncover Link Between Chronic Stress and Suppression of Brain’s Ability to Resist Junk Food Cravings in Mice


When stress hits, it’s not uncommon to find ourselves reaching for that tempting snack from the vending machine or craving a sugary treat to ease our worries. Interestingly, there is a scientific explanation behind this phenomenon.

A recent study published in the journal Neuron conducted by scientists from the Garvan Institute of Medical Research in Sydney delved into the relationship between stress, the brain, and our eating habits. Their findings revealed that stress can induce changes in the brain, leading to the development of unhealthy habits and weight gain.

However, it’s crucial to understand that the relationship between stress, food cravings, and eating behaviour is more intricate in humans. Attempting to restrict our food intake, especially during stressful times, can actually be counterproductive.

But why do we turn to food when we’re stressed? The answer lies in the brain’s reward system. Enjoying a delicious snack triggers a response in the brain that brings us a sense of comfort and relaxation.

Professor Herbert Herzog, a visiting scientist at the Garvan Institute’s Eating Disorders lab and senior author of the study, explains that during stressful situations, healthy food may not provide the same reward boost as indulging in chips or sweets. Clinical psychologist Louise Adams from Untrapped Academy spoke to the ABC and highlighted that seeking pleasure through food during challenging times is a natural response that makes sense.

Dr. Adams highlights the influence of Australia’s prevalent diet culture, which often leads to feelings of guilt about our food choices and a constant pursuit of eating “correctly.” Understanding the complex relationship between stress, food cravings, and emotional well-being can help foster a healthier approach to eating and self-care.

Stress has a significant effect on our brain’s regulation of food consumption. Normally, the brain has mechanisms in place, such as the anti-rewards system, to control our intake of sugary and fatty foods. This system, located in a brain region called the lateral habenula, helps limit the pleasure derived from eating unhealthy foods.

However, studies on mice conducted by the Garvan Institute of Medical Research have shown that chronic stress can override this natural off-switch. When the stressed mice were exposed to a challenging situation, their brain’s anti-rewards system did not activate as it would in non-stressed conditions. Similar neural pathways and key molecules are believed to be involved in humans as well.

The implications for human health are concerning, as chronic stress can lead to an increased consumption of comfort foods and weight gain. The stressed mice in the study ate twice as much as their relaxed counterparts, resulting in twice the amount of weight gain. Scientists were able to intervene in the mice’s eating behaviour by blocking a stress-related molecule, but this is not feasible for humans.

Professor Herzog suggests focusing on reducing stress levels, acknowledging that it is easier said than done. Being mindful of the amount and type of food consumed during stressful periods is also important. While it is ideal to opt for healthier choices like fresh fruits, clinical psychologist Dr. Adams emphasises the need to reconsider our relationship with food and remove the guilt associated with seeking pleasure during stressful times. She reassures that finding comfort in food is a perfectly human and understandable response.