The Study
Severe negative energy balance during 21 d at high altitude decreases fat‐free mass regardless of dietary protein intake: a randomized controlled trial
This study tested whether eating more protein helps keep your muscles from shrinking when you're very hungry and at a high mountain. It found that even with more protein, muscles still shrank — so being super hungry was the real problem. But this only happened in 17 healthy guys, so we can't say it's true for everyone.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists gave men a very low-calorie diet at high altitude and tested if eating more protein helped them keep their muscle.
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 546 / 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.
- 1Eating more protein didn't protect muscle — your body still broke down muscle even with extra protein when you're in a huge calorie deficit at high altitude.
- 2Men lost about 3.6 kg of muscle and 3.6 kg of fat, no matter if they ate 1 or 2 grams of protein per kg of body weight.
- 3Those eating more protein burned more protein and had worse overall protein balance.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The FASEB Journal
Year
2017
Authors
C. Berryman, A. Young, J. Karl, R. Kenefick, Lee M. Margolis, R. Cole, J. Carbone, H. Lieberman, Il-Young Kim, A. Ferrando, Stefan M. Pasiako
Related Content
Claims (4)
To lose body fat, you must consume fewer calories than you expend, and the size of this calorie deficit has a greater impact on fat loss than whether you do running, weightlifting, or other forms of exercise.
When healthy adult men are in a state of severe calorie deficit at high altitude, consuming 2.0 grams of protein per kilogram of body weight per day leads to a higher rate of protein breakdown compared to consuming 1.0 gram per kilogram, resulting in a greater overall loss of body protein.
When healthy adult men at high altitude consume significantly fewer calories than they burn for three weeks, they lose about 3.6 kilograms of lean body mass, whether they eat 1.0 or 2.0 grams of protein per kilogram of body weight daily.
When healthy adult males experience extreme calorie restriction at high altitudes, they lose about the same amount of body fat as they do muscle and other lean tissues.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.