The Study
Testing Protein Leverage in Lean Humans: A Randomised Controlled Experimental Study
This study showed that when people ate food with less protein, they ate more snacks and calories — but only for four days and only in healthy, lean people. It doesn't prove that eating less protein makes people gain weight over time.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
When people eat food with less protein, their body tries to get more protein by making them eat more food — but not enough to get back to normal protein levels.
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 554 / 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.
- 1Yes — eating low-protein diets may cause people to snack more and gain weight over time, even if they don’t feel fuller.
- 2Eating 10% protein instead of 15% made people eat 12% more calories, mostly from snacks like chips.
- 3Eating 25% protein didn’t make them eat less.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
PLoS ONE
Year
2011
Authors
A. Gosby, A. Conigrave, N. Lau, M. Iglesias, R. Hall, S. Jebb, J. Brand-Miller, I. Caterson, D. Raubenheimer, S. Simpson
Related Content
Claims (7)
When people reduce the amount of protein in their diet to 10% of their total calories, they tend to eat more total calories without trying.
When people eat a diet with only 10% protein, they tend to consume more calories overall because they eat more savory snacks between meals, not because they eat larger meals. This suggests that lower protein levels may trigger more frequent eating starts, not reduced fullness.
When lean adults reduce their protein intake from 15% to 10% of their daily calories, they tend to eat about 12% more calories over four days, mostly by snacking more on savory foods, suggesting that lower protein levels may lead to increased overall food consumption.
When lean adults increase their protein intake from 15% to 25% of daily calories, they do not eat fewer total calories over four days, indicating that the body adjusts energy intake when protein is too low but not when protein is too high.
When people consume a diet with only 10% protein, they may eat more total calories, but their protein intake still remains lower than on higher-protein diets, suggesting the body does not fully adjust energy intake to restore protein levels.
Human eating behavior is controlled by a set daily amount of protein needed, and feelings of hunger continue until that protein amount is consumed, even if enough calories have been eaten.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.