Ultra-processed foods (UPFs) have long been linked to numerous health conditions, including obesity, heart disease, and dementia. New scientific evidence now suggests that regular consumption of these foods may physically alter the brain, potentially perpetuating a cycle of overeating. These foods, often containing additives, emulsifiers, and preservatives designed to enhance flavor and extend shelf life, are increasingly believed to contribute to the growing prevalence of obesity-related diseases.

A study published in the journal Nature explored whether these observed brain changes are a direct consequence of weight gain or occur through independent mechanisms. An international team of scientists analyzed brain scans from over 33,000 participants in the UK Biobank study. Their findings revealed that individuals who consumed higher amounts of ultra-processed foods exhibited significantly altered brain structures, which may provide insights into food addiction.

Professor Arsène Kanyamibwa, a brain science expert at the University of Helsinki and co-author of the study, explained, “Our findings suggest that higher consumption of ultra-processed foods is associated with differences in the brain. These associations could be linked to behavioral patterns such as overeating, though causal relationships cannot be confirmed by our study.” He further noted that these associations are not solely attributable to inflammation or obesity, suggesting that ingredients and additives commonly found in UPFs, such as emulsifiers, may also play a role.

The research involved 33,654 middle-aged participants who completed an online dietary questionnaire and underwent blood tests approximately eight years before their brain scans. The questionnaire included a 24-hour dietary recall covering over 200 food items, with participants asked to indicate portion sizes. Researchers estimated energy intake per item, excluding those with extreme calorie intakes (below 500 kcal or above 5,000 kcal). On average, participants consumed about 2,608 kcal daily, with just over 46 percent derived from ultra-processed foods. Foods were categorized using the NOVA system into unprocessed or minimally processed, processed ingredients, processed foods, and ultra-processed foods.

The study found that increased UPF consumption was linked to changes in brain areas governing hunger and reward circuits, suggesting that UPFs affect the brain beyond merely contributing to obesity. In the hypothalamus, a region responsible for regulating hunger, UPF consumption was associated with lower mean diffusivity, indicative of increased cell density and inflammation. This inflammation can disrupt the brain’s regulation of hunger, satiety, and reward, all of which are critical to understanding food addiction. When these circuits are impaired or overstimulated, individuals may experience stronger cravings for UPFs even when full, leading to a loss of control over eating.

Moreover, in brain regions associated with rewards and motivation, such as the nucleus accumbens and pallidum, higher UPF intake was linked to signs of reduced cell density and increased water content. Researchers suggested these changes could represent early indicators of cognitive decline, brain shrinkage, and cell loss, potentially weakening self-control and reinforcing compulsive eating habits. They concluded that damage to these brain circuits, which influence food liking and cravings, “may favor maladaptive eating, such as increased consumption of ultra-processed foods, and metabolic disease, further perpetuating a vicious cycle.”

These findings align with earlier research from the same year, which reported that consuming an additional 100g of UPFs daily, roughly equivalent to two packets of crisps, elevated the risk of life-threatening heart issues. A comprehensive review of 41 studies involving 8,286,940 adults across multiple continents revealed that each additional 100g per day of UPF consumption was associated with a 5.9 percent increased risk of cardiovascular events. Findings presented at the American College of Cardiology (ACC) Asia 2025 conference also showed a 14.5 percent higher risk of high blood pressure among adults.

The term “ultra-processed foods” broadly encompasses edible products made with colorings, sweeteners, and preservatives designed to extend shelf life. Common examples include ready meals, ice cream, and tomato ketchup. These foods are now largely synonymous with minimal nutritional value and are distinct from processed foods, such as cured meats, cheese, and fresh bread, which undergo limited alterations primarily for preservation or flavor enhancement. The United Kingdom leads Europe in UPF consumption, with an estimated 57 percent of its national diet consisting of these foods.