The 0.8 g/kg recommendation was designed to prevent deficiency. Not to optimize health.

The current Recommended Dietary Allowance (RDA) for protein is 0.8 g/kg/day for adults. This number, established by the Institute of Medicine and codified in the Dietary Reference Intakes (2005), was calculated using nitrogen balance methodology — the oldest and least precise method available for estimating protein requirements.

The problem is methodological. Nitrogen balance studies systematically overestimate nitrogen intake and underestimate nitrogen losses, producing artificially low requirement estimates. Elango et al. (2010) demonstrated in Current Opinion in Clinical Nutrition and Metabolic Care that the newer Indicator Amino Acid Oxidation (IAAO) technique — which measures the metabolic fate of a labeled amino acid across a range of protein intakes — consistently yields higher protein requirements than nitrogen balance. Using IAAO, Humayun et al. (2007) estimated the mean protein requirement for healthy adults at 0.93 g/kg/day, with a recommended intake of 1.2 g/kg/day — 50% higher than the current RDA.

For active individuals, the evidence supports even higher intakes. Morton et al. (2018) conducted a systematic review and meta-analysis in the British Journal of Sports Medicine of 49 studies (1,863 participants) and found that protein supplementation combined with resistance exercise produced greater gains in fat-free mass and strength, with benefits plateauing at approximately 1.6 g/kg/day.

Phillips et al. (2016) argued in Applied Physiology, Nutrition, and Metabolism that protein intakes of 1.2–1.6 g/kg/day would be more appropriate for healthy adults, with higher intakes (up to 2.2 g/kg/day) during caloric restriction.

Why this matters for EAA supplementation

If optimal protein intake is 1.2–2.0 g/kg/day rather than 0.8 g/kg/day, many adults have a significant protein gap. EAA supplementation provides a calorie-efficient way to close this gap — delivering the anabolic stimulus and building blocks without the caloric load of additional whole food protein.

References

1. Elango R, Humayun MA, Ball RO, Pencharz PB. Evidence that protein requirements have been significantly underestimated. Curr Opin Clin Nutr Metab Care. 2010;13(1):52-57. PubMed
2. Humayun MA, Elango R, Ball RO, Pencharz PB. Reevaluation of the protein requirement in young men with the indicator amino acid oxidation technique. Am J Clin Nutr. 2007;86(4):995-1002. PubMed
3. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. PubMed
4. Phillips SM, Chevalier S, Leidy HJ. Protein “requirements” beyond the RDA: implications for optimizing health. Appl Physiol Nutr Metab. 2016;41(5):565-572. PubMed