By John Patterson

In our fast-paced and demanding lives, stress has become an all-too-familiar companion. While seeking solace in high-calorie comfort foods may temporarily alleviate stress, recent research conducted by a team of Sydney scientists reveals the detrimental consequences of this combination. Their groundbreaking study, published in the esteemed journal Neuron, sheds light on how stress, when coupled with calorie-dense comfort food, triggers alterations in the brain that intensify cravings for sweet, highly palatable food and contribute to excessive weight gain.

Stress Overrides the Brain’s Natural Response

The research team, hailing from the prestigious Garvan Institute of Medical Research, delved into the intricate workings of the brain to comprehend the driving factors behind our eating habits during times of stress. Their investigation focused on how various regions of the brain responded to chronic stress under different dietary conditions.

Intriguingly, the researchers discovered that chronic stress impairs the brain’s natural response to satiety, allowing unceasing reward signals that foster the consumption of highly palatable food. This disruption occurred within a specific brain area known as the lateral habenula, which typically dampens these reward signals. Professor Herzog, the senior author of the study and a Visiting Scientist at the Garvan Institute, elucidates, “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.”

Chronic Stress and High-Calorie Diet: A Recipe for Weight Gain

The study further exposed the profound link between chronic stress, a high-calorie diet, and weight gain. Mice models were employed to explore the intricate interplay between these factors. The researchers observed that under normal circumstances, the lateral habenula actively protected mice on a short-term, high-fat diet from overeating. However, in chronically stressed mice, this brain region remained silent, enabling reward signals to persist and stimulate feeding for pleasure without responding to regulatory satiety signals.

The consequences were striking—stressed mice on a high-fat diet gained twice as much weight as their non-stressed counterparts on the same diet. The underlying culprit responsible for this weight gain was identified as the molecule NPY, which the brain naturally produces in response to stress. When the researchers blocked NPY from activating brain cells in the lateral habenula of stressed mice on a high-fat diet, the mice consumed less comfort food, leading to reduced weight gain.

Craving Sweet, Palatable, comfort Food Driven by Stress

Intrigued by the connection between stress and eating habits, the researchers conducted a sucralose preference test on the mice. The test allowed the mice to choose between water and artificially sweetened water. The results were compelling—stressed mice on a high-fat diet consumed three times more sucralose than their counterparts on a high-fat diet alone, indicating that stress not only heightens the reward associated with eating but also specifically triggers a craving for sweet, palatable food. Remarkably, this preference for sweetened water was absent in stressed mice on a regular diet.

Stress’s Impact on Healthy Energy Balance

While the occasional boost of energy through food during stressful situations may be understandable, the study’s findings caution against long-term stress-induced eating that is detrimental to the body. Professor Herzog emphasizes, “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 that is bad for the body long term.”

Reference:

Chi Kin Ip, Jemma Rezitis, Yue Qi, Nikita Bajaj, Julia Koller, Aitak Farzi, Yan-Chuan Shi, Ramon Tasan, Lei Zhang, Herbert Herzog. Critical role of lateral habenula circuits in the control of stress-induced palatable food consumption. Neuron, 2023; DOI: 10.1016/j.neuron.2023.05.010

About the author:

John Patterson is an avid writer and researcher who delves into the latest scientific research. With an insatiable curiosity, he translates complex concepts into accessible narratives, allowing readers to embark on a journey of discovery. Through his work, John bridges the gap between experts and the public, igniting curiosity and inspiring meaningful conversations about scientific breakthroughs.