The Study
Effects of brief starvation on muscle amino acid metabolism in nonobese man.
This study watched what happened to muscle chemicals in 22 healthy men when they didn’t eat for two days versus just overnight. It found that certain chemicals went up, but it didn’t test if not eating caused it — it just saw a pattern.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
When you fast for a couple of days, your body pulls amino acids from your muscles to make glucose for energy.
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 541 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — this shows your body prioritizes keeping your brain fueled by turning muscle into sugar during short fasts.
- 2After 60 hours without food, muscle released 69.4% more amino acids overall, with alanine increasing by 59.4%.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of clinical investigation
Year
1976
Authors
T. Pozefsky, R. G. Tancredi, R. Moxley, J. Dupré, J. Tobin
Related Content
Claims (5)
In healthy, nonobese men, fasting for 60 hours causes a measurable increase in the release of specific amino acids from forearm muscle, including alanine, threonine, serine, glycine, alpha-aminobutyrate, methionine, tyrosine, and lysine.
In healthy, nonobese men, going without food for 60 hours lowers insulin levels and raises glucagon levels, which coincides with increased release of amino acids from skeletal muscle and a metabolic shift to produce glucose from non-carbohydrate sources.
During short-term fasting, skeletal muscle releases more amino acids, but during long-term fasting, it releases fewer amino acids, showing a two-phase metabolic shift from breaking down muscle protein to preserving it.
During a 60-hour fast, healthy men release more alanine from their muscles than any other amino acid that can be turned into glucose, with a 59.4% increase, and this alanine is used by the liver to produce glucose.
In healthy men undergoing short-term fasting, lower insulin levels cause amino acids to be released from muscle tissue to produce glucose.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.