How much protein should a 70-year-old man eat to build muscle?

1. Why the RDA likely underestimates needs for older adults—and what multiple reviews now recommend

Multiple reviews and expert groups argue that the historical RDA of 0.8 g/kg/day was set to prevent deficiency and is insufficient for maintaining or building muscle in older adults. Consensus-based guidance from nutrition experts and gerontology reviews recommends at least 1.0–1.2 g/kg/day for healthy older adults and 1.2–2.0 g/kg/day for those who are malnourished or have sarcopenia, underscoring that older physiology shows anabolic resistance and thus higher protein needs ^{[1] [2] [3]}. These reviews highlight leucine-rich, high-quality proteins as important for stimulating muscle protein synthesis and recommend distributing protein across meals to stimulate anabolic responses multiple times per day ^{[3] [4]}. The overarching message: the RDA is a minimum, not an optimal target for muscle preservation or gains.

2. Clinical trial estimates for frail older adults point even higher—implications for a 70-year-old with sarcopenia

A February 2025 metabolic study using the indicator amino acid oxidation method estimated mean average protein requirements of 1.21 g/kg/day and recommended intakes near 1.54 g/kg/day for older adults with sarcopenia, significantly above older recommendations ^[5]. These controlled metabolic data indicate that older adults with measurable muscle loss often require substantially more protein to maximally stimulate synthesis. For a 70-year-old man weighing 75 kg (≈165 lb), that equates to roughly 90–115 grams per day if sarcopenic—substantially higher than the RDA. The study authors caution about sample size and generalizability, but the result aligns with clinical guidance prioritizing higher intakes for vulnerable subgroups ^{[5] [2]}.

3. Observational and intervention studies: lower bounds and real-world associations

Population and cohort studies identify positive associations between higher habitual protein intakes and gains or maintenance of appendicular skeletal muscle mass in older men, with some analyses suggesting benefits above ~0.54 g/kg/day relative to very low intakes, but these are minimum-effect findings rather than optimal targets ^[6]. Intervention and review literature converge on the idea that total daily protein—more than precise per-meal distribution—is the main determinant of anabolic response, although per-meal thresholds (~25–35 g of high-quality protein or ~0.4 g/kg/meal) are often recommended to ensure each meal stimulates muscle protein synthesis ^{[3] [4]}. The practical takeaway: steady, higher daily protein with resistance exercise produces the best outcomes.

4. Practical translation: what this means for common body weights and meal patterns

Translating expert ranges into everyday prescriptions gives clear benchmarks: for a 70-year-old man weighing 68–80 kg (150–175 lb), 1.0–1.2 g/kg/day equals about 68–96 g/day, while 1.2–1.5 g/kg/day equals about 82–120 g/day—and values near 1.5 g/kg/day or higher may be appropriate when sarcopenia or acute illness is present ^{[4] [2] [5]}. Many sources also recommend aiming for ~25–35 g of high-quality protein per meal to stimulate muscle synthesis repeatedly, and emphasize leucine-rich sources (animal proteins or appropriately combined plant proteins) as more effective per gram ^{[3] [4]}. This frames realistic grocery- and meal-planning targets tied to measurable daily numbers.

5. Points of disagreement, limitations, and where the evidence is weakest

Disagreement centers on precise cutoffs, the importance of meal pattern versus total intake, and generalizability across populations. Some cohort analyses find sex-specific differences in associations, with weaker links in older women in certain studies, suggesting biological heterogeneity and the need for individualized plans ^[6]. Metabolic trials showing very high requirements for sarcopenic people have small samples and may not represent all older adults ^[5]. Reviewers also note that while increasing protein appears safe for most older adults, long-term randomized trials with functional endpoints remain limited, and clinicians must consider comorbidities like kidney disease when recommending high intakes ^{[1] [2]}.

6. Bottom line for a 70-year-old man wanting to build muscle—clear, evidence-based guidance

For a generally healthy 70-year-old man engaging in resistance training, aim for 1.0–1.2 g/kg/day as a reasonable starting point, increasing toward 1.2–1.5+ g/kg/day if sarcopenic, malnourished, or in recovery—translating to roughly 70–115 grams/day depending on weight and health status. Prioritize high-quality, leucine-rich proteins spread across meals (25–35 g/meal) and combine with progressive resistance exercise; consult a clinician if there are kidney-related illnesses or other medical concerns. These recommendations synthesize recent reviews, cohort findings, and metabolic trial estimates to provide a practical, evidence-based target range ^{[1] [5] [3] [4]}.