A new study has found that people who eat minimally processed foods and cook from scratch lose twice as much weight as those who consume ultra-processed ready meals, even when the nutritional profiles are identical. The research, conducted by University College London and UCL Hospitals NHS Trust, provides the first clear evidence linking ultra-processed foods (UPFs) directly to weight gain.
In the eight-week trial, 55 adults with obesity followed two diets in turn, each matched for calories, fat, salt, and sugar. One diet consisted of UPFs such as breakfast bars and ready-made lasagne, while the other used minimally processed foods like oats, natural yoghurt, and homemade spaghetti bolognese. Participants on the minimally processed diet ate 290 fewer calories per day and lost 2% of their body weight, compared with 120 fewer calories and 1% weight loss for the UPF group. Fat loss was also significantly greater.
Professor Chris van Tulleken, an author of the study, said the global food system drives obesity through cheap, unhealthy food. 'This study highlights the importance of ultra-processing in driving health outcomes beyond just nutrients,' he said. 'It underlines the need to shift policy away from individual responsibility and onto environmental drivers like the influence of multinational food companies.'
The researchers found that cravings improved on the minimally processed diet, despite weight loss typically increasing them. They recommended warning labels, marketing restrictions, and taxes on UPFs to make healthy diets more affordable. Dr Adrian Brown noted that the cost-of-living crisis makes healthy food up to twice as expensive as unhealthy options. The Department of Health and Social Care said it has commissioned further research on UPFs.
