A new study published on January 21, 2026, in *The American Journal of Clinical Nutrition* has found that eating unprocessed foods not only leads to increased food intake by weight but also reduces overall calorie consumption. This surprising result highlights the body’s natural preference for nutrition over empty calories when given wholesome options.
Unprocessed Foods Lead to Smart, Nutrient-Rich Choices
The research, led by Professor Jeff Brunstrom of the University of Bristol, builds upon a 2019 clinical trial by Dr. Kevin Hall of the US National Institutes of Health. While the original study revealed the weight gain linked to ultra-processed foods (UPFs), this new analysis offers a deeper insight: individuals on a whole foods diet consumed 57% more food by weight than those on a diet rich in processed meals but still took in an average of 330 fewer calories per day.
The findings suggest that when people are offered unprocessed options, they instinctively choose nutrient-rich foods that balance fullness and enjoyment while lowering calorie intake. “Our dietary choices aren’t random; we make smarter decisions when foods are presented in their natural state,” Brunstrom stated in *The Independent*.
Participants eating whole foods such as fruits and vegetables, rather than calorie-dense options like pasta or meat, found themselves making smarter food choices. This shift didn’t just result in more food by weight—it also contributed to a healthier balance of calories and essential nutrients.
In contrast, participants who consumed ultra-processed foods took in 508 more calories daily, leading to an average two-pound weight gain in a single week. They also risked missing out on key micronutrients unless artificially added through fortification, highlighting a significant downside to UPFs.
Interestingly, although UPFs sometimes contain more vitamins and minerals than their whole food counterparts, they do so alongside a large number of calories. For example, the highest vitamin A content in the processed foods group came from calorie-dense items like French toast sticks and pancakes, while those on the whole foods diet received their nutrients from lower-calorie choices such as carrots and spinach.
According to Dr. Annika Flynn, a senior research associate at the University of Bristol, this phenomenon leads to a “micronutrient deleveraging” effect, where the presence of high-calorie, nutrient-rich foods pushes people toward overeating. Whole foods, by contrast, encourage a healthier balance, steering people towards nutrient-dense fruits and vegetables rather than higher-calorie alternatives.
Professor Brunstrom further emphasized that overeating isn’t the core issue—it’s the quality of food choices. The study showed that participants on the whole-foods diet ate far more food, but their natural inclination toward nutrient-rich options helped them avoid the calorie overload associated with processed diets.
This study challenges conventional diet wisdom, suggesting that weight management isn’t just about eating less—it’s about choosing the right foods. By providing the body with unprocessed, nutrient-packed options, the study implies that people can naturally regulate calorie intake and improve overall health without resorting to restrictive eating patterns.
The research has broader implications for public health, especially as ultra-processed foods continue to dominate diets worldwide. As the findings suggest, making smarter food choices—rather than simply reducing portions—may be the key to tackling obesity and malnutrition in modern society.
