Researchers at the University of California, San Francisco identified a feedback mechanism in animal models that may help explain why people under chronic stress crave so-called “comfort foods.” In rats, stress triggers the release of the steroid hormone corticosterone—the rodent equivalent of human cortisol. Rather than suppressing appetite, this hormone increased pleasure-seeking behavior roughly 24 hours after a stressful event, driving the animals to seek high-calorie foods. In the experiments, the preferred foods were sugar and fat (specifically sugar and lard).
The findings offer insight into why stress in humans is often followed by cravings for calorie-dense foods such as sweets or greasy fast food. The hormonal stress response appears to prime the brain to seek rapid energy, even when no true energy deficit exists.
The research also sheds light on the connection between chronic stress and abdominal obesity. Rats exposed to ongoing stress gained weight preferentially around the abdomen. Interestingly, the accumulated fat appeared to dampen the stress response itself. The researchers proposed that fat tissue sends metabolic signals back to the brain that partially inhibit stress signaling. In effect, abdominal fat may act as a short-term brake on the stress system.
This creates a biological paradox. Acute stress—such as a brief frightening or frustrating event—normally resolves through a built-in negative feedback loop within the hypothalamic-pituitary-adrenal (HPA) axis. Chronic stress, however—persistent worry, repeated frustration, or ongoing life pressures—disrupts this regulation. Over time, this dysregulation contributes to depression, central obesity, insulin resistance, metabolic syndrome (elevated LDL cholesterol, low HDL, high triglycerides, and high blood pressure), cardiovascular disease, and even loss of brain tissue in stress-sensitive regions.
“Our studies suggest that comfort food applies the brakes on a key element of chronic stress,” said study co-author Norman Pecoraro, PhD. “This may help explain why people experiencing stress, anxiety, or depression often turn to these foods.” The same mechanism may also help explain behaviors such as nighttime binge eating and bulimia.
From an evolutionary perspective, this response makes sense. In the wild, chronic stress usually signals real threats—predators, food scarcity, disease, or environmental danger. Under those conditions, seeking high-energy food improves survival. Corticosterone (or cortisol in humans) heightens vigilance while simultaneously pushing the organism to secure fuel. Once food is obtained, stress signaling is reduced.
In modern society, however, the threats are rarely physical. Deadlines, financial strain, relationship conflict, and traffic congestion activate the same ancient stress pathways—but without the energy demands that originally justified them. The stressed office worker reaches for chocolate or fast food for the same biological reason a threatened animal seeks calorie-dense nourishment, even though the outcome now worsens metabolic health.
In a culture already struggling with obesity, type 2 diabetes, and cardiovascular disease, relying on food to manage stress only compounds the problem. More adaptive strategies—such as regular physical activity, deep breathing, yoga, meditation, or even simple relaxation practices like warm baths—can activate reward and calming pathways in the brain without the metabolic cost. These approaches help reduce stress at its source rather than masking it, supporting both psychological resilience and long-term metabolic health.
