Minimally Processed Foods Yield Twice the Weight Loss in UCL Study

Eating in line with national nutrition guidelines can promote weight loss even when menus rely heavily on packaged foods, but new research suggests that sticking to minimally processed ingredients produces markedly better results. In the longest real-world test of its kind, University College London scientists enrolled 55 overweight or obese adults in an eight-week diet of either minimally processed, home-style meals or nutritionally matched ultra-processed foods such as ready-made cereals and lasagne. After a four-week wash-out, participants switched to the alternate menu. Both regimens followed the UK Eatwell Guide and were eaten ad libitum. Nevertheless, participants shed an average 1.84 kg, or 2.06 % of body weight, on the minimally processed diet—more than double the 0.88 kg (1.05 %) lost while consuming the ultra-processed meals. The whole-food approach also lowered fat mass and triglycerides and reduced cravings, while the ultra-processed plan was associated with a drop in LDL cholesterol. Lead author Samuel Dicken said the findings, published in Nature Medicine, indicate that processing level matters even when calorie and nutrient targets are met, and that current dietary guidelines may need to address how foods are made, not just what they contain. More than half of daily calories in both the UK and US now come from ultra-processed products, underscoring the potential public-health impact of the study.