Minimize in favor of whole and minimally processed foods.
UPF diet vs whole foods: +500 kcal/day consumed spontaneously; +1 kg in 2 weeks without knowing they were eating more.
View the study (RCT) →5 days of UPF in healthy young people: +63% liver fat with no change in weight.
View the study (RCT) →White matter changes in reward and cognitive regions; they persist for a week after UPF is removed.
*⏱ 2 min read
Ultra-processed foods have quietly taken over modern diets, accounting for almost 60% of the average daily intake of an American adult; unlike whole or minimally processed foods, ultra-processed foods are industrial formulations packed with additives, artificial ingredients, refined sugars, and fats designed to enhance flavor and extend shelf life, but at a significant cost to health that goes far beyond their caloric content.
A landmark study published in 2019 by researcher Kevin Hall and colleagues found that eating a diet high in ultra-processed foods led participants to consume more than 500 additional calories per day compared with when they ate a diet of unprocessed whole foods; these additional calories came entirely from a higher intake of carbohydrates and fats, causing participants to gain almost 1 kg in just 2 weeks; the proposed mechanism is that ultra-processed foods alter satiety signals and the brain's reward circuits, making overeating almost inevitable.
A study of 29 young men aged 19-27 assigned to a high-calorie diet of ultra-processed foods for 5 days showed that, although there was no weight gain or changes in peripheral insulin sensitivity or inflammatory biomarkers, liver fat increased by 63% in just 5 days, and brain insulin activity increased in specific regions related to pleasure and reward processing, with reductions in pleasure sensitivity that persisted after participants returned to a normal diet.
The high-calorie diet also damaged the integrity of white matter in brain regions responsible for reward and cognitive processing, and these changes persisted one week after the ultra-processed foods were removed from the diet; these results suggest that ultra-processed foods change how our brain works before changing the body, wiring us to overeat and to experience food cravings differently, with worrying implications for the global obesity epidemic given that most adults consume ultra-processed foods daily over years and decades.
Information, not medical advice. Scientific evidence reflects the quality of the studies.