Why We Like (Or Don't Like) Comfort Foods
Stress affects your diet — but a new study finds that there's more to the story
Posted March 23, 2015
Most people's food habits are affected by stress, whether it's losing your appetite before a work presentation, mindlessly eating from the jellybean jar at work, or finding comfort in a tub of ice cream after an argument with your significant other.
The relationship between stress and eating has roots in our evolutionary past. Life was no picnic for our ancestors. It is believed that humans evolved in environments in which food could be scarce, and its availability fluctuated in accordance with the seasons. In order to cope with this unpredictability, we developed a “better safe than sorry strategy.” We are prone to overeat when food is available, and can store excess energy as fat which we can tap into the next time food runs out.
Moreover, it has been argued that stress might trigger foraging behaviors. Acute stress suppresses our appetite, perhaps because it would be self-defeating to search for food while in the midst of fending off an immediate threat. By contrast, chronic stress increases our appetite. Chronic stress arises when there is ongoing adversity in the environment, such as concerns about food security and personal safety. Thus, chronic stress makes us hungry — and yet also encourages the preference for energy-dense food. Energy-dense foods, which are often, and unsurprisingly, high in fat and sugar, are a go-to food when experiencing chronic stress. It's no wonder, as they spark dopamine production in the brain’s reward center, bringing on feelings of pleasure and restoring mood.
Now, a study conducted by Jim Swaffield and S. Craig Roberts investigates how environmental conditions might change food preferences across a wide range of food items of varying nutritiousness. Specifically, the researchers devised an experiment to test how the perception of a harsh vs. a safe environment might alter the preference for different types of food across the six major food categories (vegetables, fruits, grains, dairy, meats, and sweets).
Here's what Swaffield and Roberts did. First, they had participants look at images of food that were displayed on a computer screen. Next, participants rated the degree to which they wanted to eat each food item. They did this twice. But here's the twist: the participants rated how much they wanted to eat these food items before and after they were asked to read a passage that was designed to manipulate their perception of the environment as “safe” or “harsh”. The passage began, “Imagine this is your situation.” It went on to describe a young woman's living conditions in terms of employment and salary outlook, social support, and personal safety conditions. The harsh scenario described a high school dropout with highly conflicted family relationships, and who resided in a dangerous neighborhood. By contrast, the safe scenario was far more rosy: the young woman had a stable job and a healthy savings, supportive parents, and a residence in a safe and clean area.
What did the researchers find? As expected, cues of environmental harshness heightened the desirability of energy-dense food items, especially meats and sweets. In particular, bacon, cookies, chocolate, and butter were much to the participants' liking. These results support the notion that harsh environmental conditions increase perceptions of food scarcity, which in turn sets off foraging behaviors — with a focus on high calorie foods. At the same time, however, the investigators found that the safe scenario diminished the preference for energy dense foods. So when the environment is perceived as safe, the desire for high calorie foods decreases.
The authors note that although their study found that cues of environmental conditions can alter food preferences, it doesn't mean that manipulations of the environment as safe or harsh would necessarily change a person's actual caloric intake. Investigating what people would literally eat under these sorts of experimental conditions is fodder for future studies, they say. But the next time you go for a slice of cake you really don't need, it might be worth it to consider whether it's the stress that's talking.
Vinita Mehta, Ph.D. is a licensed Clinical Psychologist in Washington, D.C., and an expert on relationships, managing anxiety and stress, and building health and resilience. Dr. Mehta provides speaking engagements for your organization and psychotherapy for adults. She has successfully worked with individuals struggling with depression, anxiety, and life transitions, with a growing specialization in recovery from trauma and abuse. She is also the author of the forthcoming book, Paleo Love: How Our Stone Age Bodies Complicate Modern Relationships.