Several common foods and drinks can raise cortisol, your body’s primary stress hormone. Caffeine is the most well-documented culprit, but alcohol, added sugars, and certain artificial sweeteners also play a role. The effect depends on how much you consume and how often, with habitual intake sometimes causing lasting changes to your stress hormone system.
Caffeine Has the Strongest Direct Effect
Coffee, energy drinks, and other caffeinated beverages directly stimulate the adrenal glands to produce more cortisol. Caffeine works by boosting a key protein that kicks off the cortisol production chain. This protein controls the first and most important step in making stress hormones: moving cholesterol into the part of the cell where it gets converted into cortisol. In lab studies on human adrenal cells, caffeine increased cortisol production by about 24% at moderate concentrations.
What makes caffeine particularly notable is that its effects appear to linger. When researchers removed caffeine from adrenal cells after just 48 hours of exposure, the cells continued producing elevated levels of the cortisol-triggering protein for multiple generations of cell division afterward. This suggests that regular caffeine intake may cause semi-permanent changes to how your adrenal glands behave, not just a temporary spike that fades when the coffee wears off. The cortisol response was also dose-dependent, meaning more caffeine translated to more cortisol across every amount tested.
For most people, a cup or two of coffee in the morning aligns with the body’s natural cortisol peak and is unlikely to cause problems. But heavy caffeine consumption throughout the day, especially during the afternoon and evening when cortisol should naturally be declining, can keep levels elevated when your body is trying to wind down.
Alcohol Raises Cortisol Even on Days You Don’t Drink
Alcohol activates the body’s central stress response system, the loop connecting your brain’s hypothalamus, pituitary gland, and adrenal glands. A study published in The Journal of Clinical Endocrinology & Metabolism tracked this relationship in an aging population and found that men showed a 3% increase in cortisol for every additional unit of alcohol consumed per week. That adds up quickly: someone drinking 10 units a week could have roughly 30% higher cortisol than a non-drinker.
Heavy drinkers also showed a flattened cortisol curve throughout the day. Normally, cortisol peaks in the morning and drops steadily toward bedtime. In heavy drinkers, that decline was blunted, meaning cortisol stayed higher than it should during evening hours. Crucially, these elevated levels weren’t just present on drinking days. They persisted even when no alcohol was consumed, pointing to chronic changes in how the stress system regulates itself. Moderate drinkers showed a less pronounced version of this pattern, suggesting the effect scales with how much and how often you drink.
Added Sugars and Refined Carbohydrates
The relationship between sugar and cortisol is less straightforward than it’s often portrayed. The proposed mechanism is that high-sugar foods cause a rapid blood sugar spike followed by a crash, and the crash triggers cortisol release as your body scrambles to restore glucose levels. Research consistently links high sugar intake with broader stress hormone disruption and elevated cortisol over time.
However, controlled studies comparing high-glycemic diets (those that spike blood sugar quickly) to low-glycemic diets haven’t always shown a clear, immediate difference in cortisol levels between the two. The effect may be more cumulative than acute. A diet consistently high in added sugars and refined grains appears to keep the stress system slightly more activated over weeks and months, rather than producing dramatic cortisol spikes after individual meals. One intervention study found that a diet resembling the typical American pattern, higher in added sugars, refined grains, and total fat, was associated with greater cortisol responsiveness over eight weeks compared to a cleaner whole-food diet with more complex carbohydrates.
The practical takeaway: a slice of cake at a birthday party isn’t going to meaningfully alter your cortisol. A daily diet built around soda, white bread, sweetened snacks, and sugary cereals likely will, over time.
Artificial Sweeteners May Act as Chemical Stressors
Aspartame, one of the most widely used artificial sweeteners found in diet sodas and sugar-free products, has been identified as a potential chemical stressor that can elevate cortisol. Research suggests it raises plasma cortisol levels and also increases another stress hormone, adrenocorticotropin, which signals the adrenal glands to produce more cortisol.
Part of the mechanism may involve the gut. Aspartame appears to alter gut bacteria composition, and disrupted gut bacteria can independently trigger stress hormone release. The combination of direct hormonal effects and gut changes may explain why artificial sweeteners, despite containing no calories or sugar, could still influence your stress response. This area of research is still developing, and the magnitude of the effect in typical dietary amounts isn’t fully pinned down, but it complicates the assumption that switching from sugar to artificial sweeteners automatically reduces the metabolic stress of your diet.
High-Fat Meals and Stress Reactivity
Meals high in saturated fat don’t just raise cortisol on their own. They appear to amplify your cortisol response to other stressors. Studies have shown that high-fat meals exacerbate cardiovascular and nervous system responses to stress, meaning a stressful event after a greasy meal may produce a larger cortisol spike than the same event on an empty stomach or after a lighter meal.
An eight-week dietary intervention study compared a standard American diet (34% fat, more saturated fat and refined ingredients) against a healthier pattern (26% fat, more whole grains and complex carbohydrates). While the researchers didn’t find a direct statistical link between fat intake and baseline cortisol, the healthier diet dampened cortisol responsiveness over time. In other words, what you eat regularly shapes how dramatically your body reacts to stress, even if a single high-fat meal doesn’t send cortisol through the roof on its own.
The Pattern Matters More Than Any Single Food
The foods most consistently linked to elevated cortisol, caffeine, alcohol, added sugars, and highly processed items high in saturated fat, tend to cluster together in typical Western diets. Their effects compound. Someone drinking multiple cups of coffee, having a few drinks in the evening, and eating processed snacks throughout the day isn’t just experiencing one cortisol trigger. They’re layering several on top of each other, day after day.
Cortisol is meant to spike in response to acute stress and then come back down. The real problem isn’t a temporary rise after a cup of coffee. It’s a dietary pattern that keeps cortisol chronically elevated or blunts the natural daily rhythm so it never properly drops. That sustained elevation is what’s linked to weight gain around the midsection, poor sleep, weakened immune function, and mood changes. Reducing the foods on this list doesn’t need to be all-or-nothing. Even cutting back on one or two of the biggest contributors, particularly caffeine later in the day and regular alcohol, can meaningfully shift your cortisol profile.