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A new study explored the mechanisms involved in the increased consumption of highly palatable food during periods of high stress. The study was done by a team of researchers at the Garvan Institute of Medical Research in Sydney, Australia, and it was published in the online journal Neuron.
How chronic stress
In this study, scientists initiated their experiments to understand the impact of chronic stress on eating behaviors in mice. They discovered the critical role of the lateral habenula, a brain area involved in the homeostatic regulation of the reward response in driving the eating behaviors of the mice.
In mice that experienced short-term stress, the lateral habenula remained active and switched off the reward response in the brain. The mice consumed high-fat foods but didn’t overeat. The lateral habenula activation led to a feeling of satiety in these mice. However, in chronically stressed mice, this area of the brain (lateral habenula) didn’t get activated. The mice didn’t develop a feeling of satiety and consumed more high-fatty foods in the absence of reward response regulation. Consequently, the stressed mice on a high-fat diet gained twice the weight compared to mice that were not chronically stressed.
Sucralose preference test
Scientists took the next step of analyzing if chronic stress leads to increased consumption of sweet, palatable foods. They provided the mice with water and sweetened water. Stressed mice that were consuming high-fat foods drank the artificially sweetened water three times now than the mice that were consuming high-fat foods but were not stressed. The researchers also observed that mice that were stressed but were on a regular diet didn’t exhibit this preference for sweetened drinks.
What did the study reveal?
Based on this study, the scientists concluded that chronic stress leads to the suspension of reward regulatory mechanisms in the mice’s brains promoting nonstop high-fat food consumption. Furthermore, they also observed that chronic stress not only promotes overeating but also drives a desire to eat sweetened palatable foods.
Limitations of this study
Mentioning the limitations of this study, the scientists emphasized that this study was done in mice so its results may not be generalizable to humans. They also encouraged further research to explore the role of other brain areas that are involved in these mechanisms.
This study establishes the critical role of chronic stress in driving eating behaviors and consequent weight gain. It provides insights into how a brain region and specific molecules drive these changes. Moreover, it highlights how the reward regulatory mechanisms remain unactivated during chronic stress to enhance the unchecked consumption of fatty and sweet foods. In addition, this study sheds light on the possible prevention strategies to alleviate adverse events associated with chronic stress. These strategies can help prevent weight gain, metabolic diseases, and cardiac and endocrine diseases. Learning about the mechanisms learned through this study, many people can manage their stress better and keep their mental health and the associated adverse behaviors in check.
Ip, C. K., Rezitis, J., Qi, Y., Bajaj, N., Koller, J., Farzi, A., Shi, Y., Tasan, R., Zhang, L., & Herzog, H. (2023). Critical role of lateral habenula circuits in the control of stress-induced palatable food consumption. Neuron. https://doi.org/10.1016/j.neuron.2023.05.010