BLOG

If you can relate to the experience of coming home after a long day of work with insatiable cravings for your favorite comfort foods, you are not alone. Stress often leads us to indulge, whether that’s in a pint of ice cream, a bag of chips or a few too many slices of pizza. While it may be frustrating, there are in fact psychological and physiological explanations driving this habit.

“…this once-adaptive response can contribute to unhealthy eating habits and weight gain.”

A preference for comfort foods during times of stress is often believed to be a survival mechanism as our ancestors would have likely turned to energy-dense foods to better cope with acute life stresses. In the modern world, however, where energy-dense foods are abundant and easily accessible, and the chronic stress experienced does not require the increased physical performance needed for the fight and flight response, this once-adaptive response can contribute to unhealthy eating habits and weight gain.

“…cravings are typically for high-calorie, sugary, salty and fatty foods…”

When we are acutely stressed, our bodies release hormones such as cortisol and epinephrine. In the short term, these hormones may decrease appetite, but in the case of persistent stress which is the most common form of stress today, they can have the opposite effect. Elevated cortisol stimulates the release of neuropeptides like ghrelin and neuropeptide Y (NPY) that drive our appetite and cravings. Ghrelin is released from specialized cells in the stomach and from neurons in the brain, the hypothalamic arcuate nucleus (ARC). It also interacts with neuropeptide Y neurons in the ARC, which greatly impact food intake.

Further, these cravings are typically for high-calorie, sugary, salty and fatty foods as they temporarily make us feel better psychologically by stimulating the brain’s reward centers. One such reward signal is dopamine, a neurotransmitter that promotes feelings of satisfaction and pleasure as well as motivation. This motivation often causes us to seek out more of what made us feel good in the first place, leading to persistent cravings and compulsive overindulgences in these foods.

“The brain is continuously rewarded for eating and does not receive signals that the body has had enough.”

A 2023 study on mice published in the journal Neuron found that a high-calorie diet combined with a chronic laboratory stressor drives an appetite for these so-called comfort foods. Stress can seemingly inhibit typical brain signaling thereby reducing the homeostatic satiety effect. These satiety signals include glucagon-like peptide 1 (GLP1) and Cholecystokinin (CCK), which are released in the gut and reach the brain either in circulation or via the vagus nerve. Under stress, the brain is continuously rewarded for eating and does not receive signals that the signals from the gut that the body has had enough. The increase in cortisol leads to a reduction in cerebral blood flow in neural regions that regulate food intake.

If the brain does not get the message that the body is full or satiated, it becomes difficult to put down the carton of ice cream. Consequently, mice in the study which were fed a high-fat diet while being highly stressed gained twice as much weight as mice fed the same diet without added stress.

“Neuropeptide Y may be directly associated with increased caloric intake in times of stress.”

Researchers also found that when the molecule Neuropeptide Y was inhibited in the stressed mice, they ate less and gained less weight. Neuropeptide Y is naturally produced in the brain in response to stress and “stimulates food intake with a preferential effect on carbohydrate intake.” These findings suggest Neuropeptide Y may be one of the mechanisms that is directly associated with increased caloric intake in times of stress.

Lastly, researchers discovered mice fed a high-fat diet while under stress had a strong preference for sweet water (sweetened with the non-absorbable, zero calorie, non-nutritive sweetener Sucralose) compared to mice fed a high-fat diet without stress and mice fed a relatively lower fat diet while under stress, highlighting the effect of stress on the preference for sweet foods, regardless of caloric density.

These findings reflect how high stress coupled with a high-fat diet can lead to greater cravings than a high stress or a high-fat diet alone. This also suggests that Neuropeptide Y, given its propensity to increase carbohydrate intake, may have less of an impact on appetite in those consuming a diet low in simple carbohydrates.

“Consuming a balanced diet, even during times of stress, may prevent overeating…”

While chronic stress is common in our modern world, efforts to mitigate stress when possible may be beneficial in those struggling to manage cravings and weight gain. Consuming a balanced diet, even during times of stress, may prevent overeating as well as damaging patterns of unhealthy eating habits. Additionally, engaging in alternate behaviors during times of stress such as regular physical exercise, spending time with friends and family, adopting a meditation practice and spending more time in nature can provide a similar release of dopamine that will boost mood without promoting a cycle of persistent cravings.