Cutting out ultra-processed foods can speed up weight loss, study shows

ITV News

3 days ago

Cutting out ultra-processed foods from your diet can help you lose weight twice as quickly, according to researchers at University College London, after the longest-running clinical trial of its kind. Science Correspondent Martin Stew, who has been following the trial from the beginning, reports on its findings
Cutting out ultra-processed foods from your diet can help you lose weight twice as quickly, according to researchers at University College London.
In the longest-running clinical trial of its kind, 55 participants followed two different nutritionally balanced diets over two eight-week periods.
One diet consisted solely of minimally processed foods (MPFs), while the other included ultra-processed foods (UPFs).
UPFs often contain ingredients such as emulsifiers and stabilisers that you wouldn't typically find in a home kitchen, foods like cereals, sliced bread and ready-made meals.
After each eight-week phase, both groups experienced weight loss, likely due to the improved nutritional quality of their diets compared to their usual eating habits.
However, the reduction was more significant in the MPF diet group, a 2.06% decrease in body weight compared to 1.05% in the UPF group.
Dr Samuel Dicken, the study's lead author from the UCL Centre for Obesity Research and the UCL Department of Behavioural Science & Health, explained: 'If these results were scaled up over a year, we'd expect to see around a 13% weight reduction in men and 9% in women on the minimally processed diet, compared to only about 4% in men and 5% in women on the ultra-processed diet.
"Over time, the differences become quite substantial.'
ITV News has been following the experiences of two participants for more than a year.
Suzy, who lost 5kg during the MPF diet, gained some weight back while eating UPFs.
She has since chosen to reduce her intake of UPFs significantly.
'I feel really good,' she told ITV News. 'I feel in control of what I'm eating, which is a really nice feeling.'
Similarly, 62-year-old David Bones shared his experience: 'It's like a fog lifting," he said. "You go from living in this fog, thinking that's normal, and then suddenly everything feels clearer—you feel better physically and mentally.
"It's a huge improvement.'
In both diets, participants were given more food than they needed.
The trial found that eating MPF resulted in fewer cravings.
The less calorie-dense food was often more effort to prepare and eat, which may have been a reason why participants chose to stop eating sooner.
Professor Chris van Tulleken, an author of the study from UCL Division of Infection & Immunity, commented: 'The current global food system promotes poor health and obesity, largely because of the widespread availability of cheap, unhealthy foods.
"This study highlights how ultra-processing influences health outcomes beyond just the nutrients, like fat, salt, and sugar.
"It underscores the need to shift policy focus away from individual responsibility and towards the environmental factors shaped by multinational food companies that promote unhealthy food environments.'
The trial also examined secondary health markers, including blood pressure, heart rate, liver function, glucose levels, cholesterol and inflammation.
Generally, there were no significant differences in these markers between the diets. The researchers caution that longer studies would be needed to properly investigate these measures in relation to changes in weight and fat mass.
When I caught up with Suzy at her final weigh-in last week, she had successfully maintained her weight loss. She shared that she has adopted permanent lifestyle changes.
'You could say 100% no ultra-processed foods, but that would be really difficult with friends and family,' she explained.
'For me, it's about finding a balance, still enjoying some of the foods others eat but not making UPFs a regular part of every meal and snack. That approach has worked really well for me.'