The Study
Human protein requirements: a long-term metabolic nitrogen balance study in young men to evaulate the 1973 FAO/WHO safe level of egg protein intake.
This study watched six guys eat a specific amount of protein for a long time and noticed some changes in their bodies. But it didn't compare them to other people or randomly assign diets, so we can't say the protein caused those changes—it just shows what happened in these six people.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists tested if eating a little bit of egg protein every day was enough for healthy young men to stay strong and healthy over time.
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 525 / 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 — eating too little protein can cause muscle loss and stress on the liver, even in healthy young men.
- 2At 0.59 g protein/kg/day, 4 out of 6 men lost muscle and nitrogen.
- 3When they ate 1.5 g/kg/day from milk powder, their liver enzymes returned to normal.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of nutrition
Year
1977
Authors
C. Garza, N. Scrimshaw, V. Young
Related Content
Claims (5)
Eating just 0.59 grams of egg protein per kilogram of body weight every day isn't enough to keep your body in good balance over time—it can cause your body to lose muscle and potassium, even if you're young and healthy.
When young men drank more skim milk powder to get more protein, their liver enzyme levels went back to normal quickly—this might mean that not getting enough protein can stress your liver early on.
Scientists found that we lose more nitrogen through our skin than previously thought—about three times more. This means the old guidelines for how much protein we need might be too low.
A long-standing guideline says people should eat 0.57 grams of egg protein per kilogram of body weight each day, but this study suggests that might not be enough to keep healthy young men’s bodies in balance — they might need a little more, like 0.59 grams.
Eggs have a special kind of protein that helps your body keep more nitrogen instead of losing it in urine, which helps your muscles and tissues grow better.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.