Research published in Proceedings of the National Academy of Sciences (September 30, 2003; Vol. 100, No. 20:11696–11701) explored why stress often drives cravings for so-called “comfort foods.” The study focused on corticosterone production in rats—the rodent equivalent of the human stress hormone cortisol.
In the study, stress reliably increased corticosterone levels. Elevated corticosterone, in turn, promoted pleasure-seeking behaviors, including the consumption of high-energy foods such as sugar and fat. These foods appeared to have a regulatory effect on the stress response itself.
Interestingly, consumption of comfort foods reduced activity of the stress-response system. As study co-author Norman Pecoraro, PhD, explained, “Our studies suggest that comfort food applies the brakes on a key element of chronic stress.” From a biological perspective, this response makes sense: during periods of acute stress, injury, or scarcity, high-energy food would be advantageous for survival.
In environments characterized by war, famine, or epidemics, access to calorie-dense food can be protective. In modern societies, however, stress tends to be chronic rather than acute, while high-energy foods are abundant. The study found that increased abdominal fat was associated with reduced production of stress hormones, suggesting a feedback mechanism. As Pecoraro noted, this may be the body’s way of signaling the brain, “It’s okay—you’re refueled with high-energy food.”
This mechanism may help explain why weight loss is often difficult. Caloric restriction itself can be perceived as a stressor, increasing adrenal hormone output and intensifying cravings for comfort foods. From this perspective, stress physiology and eating behavior are closely intertwined, particularly in environments where psychological stress is high and food availability is constant.
