The Study
A randomized controlled trial to isolate the effects of fasting and energy restriction on weight loss and metabolic health in lean adults
This study compared two ways of eating: one where people ate less every day, and another where they fasted every other day. Because people were randomly assigned, we can say that one method probably caused more fat loss than the other — but only for these people in these 3 weeks.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study compared two ways to lose weight: eating less every day vs. fasting every other day.
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.
- 1The difference in fat loss between daily restriction and fasting is meaningful — daily restriction worked better.
- 2Eating 75% of normal calories every day lost 1.75 kg of fat.
- 3Fasting every other day but eating the same total calories lost only 0.74 kg of fat.
- 4Fasting without eating less didn't lose any fat.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Science Translational Medicine
Year
2021
Authors
Iain Templeman, Harry A. Smith, Enhad A. Chowdhury, Yung-Chih Chen, H. Carroll, Drusus A. Johnson-Bonson, Aaron Hengist, R. Smith, Jade Creighton, D. Clayton, I. Varley, L. Karagounis, A. Wilhelmsen, K. Tsintzas, S. Reeves, J. Walhin, J. Gonzalez, D. Thompson, J. Betts
Related Content
Claims (4)
In humans, autophagy is primarily triggered by a reduction in energy intake, not by when meals are consumed during the day.
In lean adults, fasting every other day without eating fewer calories overall does not lead to a reduction in body weight or fat mass after three weeks.
In lean adults, alternate-day fasting and daily calorie restriction produce the same effects on blood sugar, insulin, and gut hormones after meals over a 3-week period.
In lean, healthy adults, eating 75% of daily maintenance calories every day for three weeks results in a 1.75-kilogram loss of body fat, which is greater than the 0.74-kilogram loss from alternate-day fasting with the same total calories.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.