Avoiding ultraprocessed foods supports healthier aging

Summary

We compared how participants fared while eating their habitual diets with how they responded to the two diets that were low in ultraprocessed foods. During the periods when participants ate fewer ultraprocessed foods, they naturally consumed fewer calories and lost weight, including total and abdominal body fat. Beyond weight loss, they also showed meaningful improvements in insulin sensitivity, healthier cholesterol levels, fewer signs of inflammation and favorable changes in hormones that help regulate appetite and metabolism. These improvements were similar whether participants followed the meat-based or the vegetarian diet. Why it matters Ultraprocessed foods make up more than half the calories consumed by most U.S. adults. Although these foods are convenient and widely available, studies that track people’s diets over time increasingly link them with obesity and age-related chronic diseases such as Type 2 diabetes and heart disease. With older adults making up a growing share of the global population, strategies that preserve metabolic health could support healthy aging. Most previous feeding studies testing how ultraprocessed foods affect people’s health haven’t reflected real-world eating, especially among Americans. For example, some studies have compared diets made up almost entirely of ultraprocessed foods with diets that contain little to none at all. Our study aimed to more closely approximate people’s experience while still closely tracking the foods they consumed. It is the first to show that for older adults a realistic reduction in ultraprocessed foods, outside the lab, has measurable health benefits beyond just losing weight. For older adults especially, maintaining metabolic health helps preserve mobility, independence and quality of life. What’s still unknown Our study was small, reflecting the complexity of studies in which researchers tightly control what participants eat. It was not designed to show whether the metabolic improvements we observe...