The Study
Ultra-processed diets cause excess calorie intake and weight gain: An inpatient randomized controlled trial of ad libitum food intake
This study gave 20 people two different diets for two weeks each and watched what they ate and how their weight changed. It shows that when they ate ultra-processed food, they ate more and gained weight — but only because they were in a lab and couldn’t choose their food. It doesn’t prove that everyone who eats junk food will get fat.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists gave people two kinds of meals — one made from whole foods and one made from packaged, processed foods — but made sure both had the same calories, sugar, fat, and protein. People ate more from the processed meals without feeling hungrier.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 560 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1That’s like eating an extra burger every day without trying — and gaining nearly 2 pounds in just two weeks, just from what kind of food you eat, not how much you want to eat.
- 2People ate 508 extra calories per day on processed diets and gained 0.9 kg in 2 weeks, even though they didn’t feel hungrier or more satisfied.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Cell metabolism
Year
2019
Authors
K. Hall, Alexis Ayuketah, R. Brychta, H. Cai, Thomas M Cassimatis, Kong Y. Chen, S. Chung, Elise Costa, A. Courville, Valerie L. Darcey, Laura A. Fletcher, C. Forde, A. Gharib, Juen Guo, Rebecca Howard, Paule Valery Joseph, Suzanne McGehee, R. Ouwerkerk, Klaudia Raisinger, Irene Rozga, Michael Stagliano, M. Walter, P. Walter, Shanna B. Yang, Megan S. Zhou
Related Content
Claims (5)
People who eat ultra-processed foods consume about 280 more kilocalories from carbohydrates and 230 more kilocalories from fat each day than those who eat less processed foods, with no change in protein intake.
When healthy adults ate ultra-processed foods for two weeks, they consumed 508 more calories per day and gained 0.9 kilograms on average, compared to when they ate unprocessed foods with the same nutrients, sugars, sodium, and fiber.
People eating ultra-processed foods report similar levels of hunger, fullness, satisfaction, and taste preference as those eating unprocessed foods, even though they consume more calories.
When people eat diets with the same amounts of protein, fat, and carbohydrates, those eating ultra-processed foods consume about 500 more calories per day than those eating whole foods.
When people eat ultra-processed foods compared to unprocessed foods with the same calories and nutrients, they eat faster at a rate 25% higher, and this faster eating is linked to consuming more total calories. Food texture and how quickly food is processed in the mouth are associated with higher overall intake.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.