Is the 1973 FAO/WHO egg protein recommendation of 0.57 g/kg/day too low for nitrogen balance in young men?

We analyzed the available evidence on the 1973 FAO/WHO egg protein recommendation of 0.57 grams per kilogram of body weight per day, and what we’ve found so far suggests this level may be slightly low for maintaining nitrogen balance in healthy young men. One study reviewed indicates that to keep nitrogen levels stable — meaning the body isn’t losing more protein than it’s gaining — young men may need closer to 0.59 grams per kilogram each day [1]. This small difference, just 0.02 grams per kilogram, adds up over time and could matter for people aiming to maintain muscle or recover from physical stress. We did not find any studies that contradicted this finding. The evidence we’ve reviewed leans toward the idea that the old recommendation might not fully meet the needs of this group, though the gap is narrow. Nitrogen balance is a way to measure whether the body is getting enough protein to repair tissues and support normal function. It’s not the same as muscle growth, but it’s a basic indicator of protein adequacy. We don’t know if this applies to women, older adults, or people with different activity levels — the study focused only on healthy young men. Our current analysis shows that while the 0.57 g/kg/day guideline has been used for decades, newer data suggests a small upward adjustment could better match what the body needs. For now, if you’re a healthy young man trying to stay in protein balance, aiming for just a bit more than the old standard — maybe 0.6 grams per kilogram — might be worth considering.