Research Updates | Other
Finding: Subjects consumed more energy and gained weight when consuming ultra-processed foods ad libitum.
Summary: Twenty inpatients (10 male and 10 female) received 14 days of unprocessed and 14 days of ultra-processed foods in a crossover design within a metabolic ward. Ultra-processed foods were as defined by the NOVA system. The meals presented were matched for energy, sugar, fat, fibre and macronutrients, however participants could eat as much as they wanted (ad libitum). Researchers were unable to match the proportion of total vs added sugar, insoluble vs total fibre, saturated vs total fat, or the ratio of n-6 vs n-3 fatty acids.
The cost of the unprocessed diet was 42% more than the ultra-processed diet. The ultra-processed food diet resulted in the consumption of around 500 calories more per day, and body weight increases (+0.9kg) correlated with the additional energy consumed. The unprocessed diet resulted in a body weight loss of 0.9kg.
Participants did not report significant differences in the pleasantness or familiarity of the meals between the ultra-processed and unprocessed diets, suggesting that the observed energy intake differences were not due to greater palatability.
Citation: Hall KD, Ayuketah A, Brychta R, Cai H et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomised controlled trial of ad libitum food intake. Cell Metabolism 2019; 30 (1): 67-77 (free to view)
Editor’s note: Read more about the ultra-processed foods in a previous issue here