Simple Food Swaps Dramatically Improve Health in Older Adults

Dramatic Results From Simple Changes

A groundbreaking study has revealed that older adults can achieve remarkable health improvements by making one simple change: reducing ultraprocessed foods in their diet. The controlled feeding study led by Moul Dey, professor in the School of Health and Human Sciences at South Dakota State University, shows that older adults who ate fewer ultra-processed foods naturally consumed fewer calories, lost weight and abdominal fat . They also showed improvements in insulin, nutrient-sensing hormones and inflammation .

On average, participants spontaneously reduced calorie intake and experienced about 10% total body fat loss and 13% belly fat loss during both diet phases, along with a 23% improvement in insulin sensitivity and favorable changes in inflammatory markers and nutrient-sensing hormone levels . Perhaps most remarkably, daily calorie intake decreased by roughly 400 calories per day, even without instructions to restrict calories .

The study involved Americans ages 65 and older, many of whom were overweight or had metabolic risk factors such as insulin resistance or high cholesterol . A total of 43 people began the dietary intervention, and 36 completed the full study .

The Power of Processing Matters More Than Nutrients

In both diets, ultraprocessed foods made up less than 15% of the total calories – a significant reduction from the typical American diet, where more than 50% of total calories comes from ultraprocessed foods . The participants followed two different eight-week diets: one included lean red meat (pork); the other was vegetarian with milk and eggs . Both approaches produced identical benefits, suggesting processing level trumps dietary philosophy.

Dey explained: "Counting nutrients is not enough. The degree of processing changes how the body handles those same nutrients. Diet quality depends on both the ingredients and the level of processing considered together" . Ultraprocessed foods are made using industrial techniques and ingredients that aren't typically used in home cooking. They often contain additives such as emulsifiers, flavorings, colors and preservatives. Common examples include packaged snacks, ready-to-eat meals and some processed meats .

What makes this research particularly significant is its real-world applicability. The diets were designed to be realistic for everyday eating, and participants were not instructed to restrict calories, lose weight or change their physical activity. Researchers prepared, portioned and provided all meals and snacks for the study. Both diets emphasized minimally processed ingredients and aligned with the 2020-2025 Dietary Guidelines for Americans .

Why This Matters for Aging Americans

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 . For older adults especially, maintaining metabolic health helps preserve mobility, independence and quality of life .

As Dey noted: "Older adults often face metabolic challenges as appetite and energy needs shift. We saw that when ultra-processed foods went down, total calories and harmful metabolic markers did, too" . This is the first study to show that for older adults a realistic reduction in ultraprocessed foods, outside the lab, has measurable health benefits beyond just losing weight .

Practical Steps Forward

The research offers hope for a practical approach to healthier aging. Saba Vaezi, a doctoral researcher in Dey's laboratory and first author of the study, said the findings show that simple substitutions, rather than restrictive dieting, can make measurable differences. "Participants did not count calories or follow complicated weight-loss instructions" .

The results suggest a simple strategy for everyday life: when grocery shopping, choosing more whole or minimally processed foods and fewer shelf-stable products with long ingredient lists may help prevent overeating and improve metabolism . As Dey concluded: "This study moves past the usual debate over whether plant-based or animal-based diets are better. Both can be health-promoting when foods are simply prepared and nutritionally balanced" .

While questions remain about implementing these changes without structured support, this research demonstrates that the path to healthier aging may be simpler than previously thought. The key isn't counting calories or following complex diet rules—it's choosing foods that look more like they did when they came from the farm than the factory.