Study Shows ‘Healthy’ Ultra-Processed Foods Can Hinder Weight Loss Efforts
Ultra-processed foods have long been associated with negative health outcomes, and a recent study indicates that even the ‘healthy’ versions of these foods can impede weight loss efforts significantly.
A team of researchers from the UK and US conducted a study involving 50 overweight individuals who participated in two separate diet programs. Both diets were matched in terms of nutrition, including equal amounts of fat, carbs, fiber, salt, and fruits and vegetables.
The main difference between the two diets was that one focused on ultra-processed foods (UPFs) such as breakfast oat bars and ready-made lasagne, while the other centered around minimally processed foods (MPFs) like overnight oats and homemade spaghetti bolognese.
Key Findings
Both diet programs resulted in weight loss, but participants on the MPF diet experienced twice as much weight loss on average compared to those on the UPF diet. Additionally, individuals on the MPF diet lost more unhealthy body fat and reported better control over unhealthy food cravings.
According to clinical scientist Samuel Dicken from University College London (UCL), “Previous research has linked ultra-processed foods with poor health outcomes, but not all ultra-processed foods are inherently unhealthy based on their nutritional profile.”
The study aimed to address gaps in knowledge regarding the impact of food processing on health outcomes such as weight, blood pressure, body composition, and food cravings.

Although the overall weight reductions were modest (2% for MPF diet and 1% for UPF diet) over the eight-week study period, the cumulative effects of avoiding ultra-processed foods could be significant over time.
Dicken explains, “If we extrapolate these results over a year, we could expect a 13% weight reduction in men and a 9% reduction in women following the minimally processed diet, compared to only a 4% reduction in men and 5% in women on the ultra-processed diet.”
Implications and Recommendations
Although the study had limitations, such as its small sample size and exclusion of individuals with dietary restrictions, it provides valuable insights into addressing the obesity crisis by following nutritional guidelines and avoiding ultra-processed foods.
Chris van Tulleken, a global health and infection researcher at UCL, emphasizes the role of ultra-processing in driving health outcomes and the importance of considering factors beyond nutrients like fat, salt, and sugar in diet-related health issues.
The findings of this study have been published in Nature Medicine, shedding light on the potential impact of food processing on weight loss and overall health.