For healthy older men doing strength training, eating 1.6 grams of protein per kilogram of body weight per day does not result in greater gains in muscular power or endurance than eating 0.8 grams per kilogram per day.
See the scientific wording
In healthy older men performing resistance training, a daily protein intake of 1.6 g/kg/d has no significant effect on muscular power or muscular endurance compared to a daily protein intake of 0.8 g/kg/d.
Very strong evidence
Randomized trialsOne good-quality study supports this claim.
What the research says
1 study reviewedSupporting (1)
Randomized Controlled TrialHuman2023
The study found no statistically significant differences between the high and low protein groups for muscular power or endurance, despite identical training protocols. This indicates protein intake above 0.8 g/kg/d does not enhance these specific adaptations in this population.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
Eating more protein increases amino acids in the blood, which turn on a cellular switch that tells muscle cells to build more protein. This leads to bigger muscle fibers over time. However, the ability to generate force quickly or sustain repeated efforts does not improve because those traits depend on how often and how intensely the muscles are trained, not on how much protein is available.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting study
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For healthy older men doing strength training, eating 1.6 grams of protein per kilogram of body weight per day does not result in greater gains in muscular power or endurance than eating 0.8 grams per kilogram per day.
Mechanism
1 studyMore protein makes muscles bigger, but it doesn't make them stronger at quick movements or better at doing many reps. Those abilities come from how often and how hard you train, not from how much protein you eat.
Eating more protein increases amino acids in the blood, which turn on a cellular switch that tells muscle cells to build more protein. This leads to bigger muscle fibers over time. However, the ability to generate force quickly or sustain repeated efforts does not improve because those traits depend on how often and how intensely the muscles are trained, not on how much protein is available.
Dietary protein intake increases plasma concentrations of essential amino acids, particularly leucine
Elevated leucine activates the mTORC1 signaling pathway in skeletal muscle fibers
mTORC1 activation increases ribosomal biogenesis and translation initiation, enhancing the rate of muscle protein synthesis
Increased protein synthesis combined with reduced protein breakdown shifts net muscle protein balance to positive
Chronic positive net protein balance over weeks leads to skeletal muscle hypertrophy and increased strength
Muscular power and endurance are determined by neural drive, fiber type recruitment patterns, and training volume, not by muscle size or protein synthesis rates
Evidence from Studies
Supporting (1)
Community contributions welcome
Contradicting (0)
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Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review and Meta-Analysis of Protein Intake at 1.6 g/kg/d vs. 0.8 g/kg/d on Muscular Power and Endurance in Older Men Undergoing Resistance Training
Population: Healthy older men (≥60 years) performing structured resistance training; Intervention: 1.6 g/kg/d protein; Comparator: 0.8 g/kg/d protein; Outcome: Changes in muscular power (e.g., peak force, jump height) and muscular endurance (e.g., repetitions to failure at fixed load); Duration: Minimum 8 weeks; Study design: Aggregates all randomized controlled trials meeting inclusion criteria.
Double-Blind, Placebo-Controlled Trial of 1.6 g/kg/d vs. 0.8 g/kg/d Protein on Muscular Power and Endurance in Older Men During 12 Weeks of Resistance Training
Population: Healthy men aged 60–75 years; Intervention: 1.6 g/kg/d protein supplementation; Comparator: 0.8 g/kg/d protein placebo; Outcome: Pre- and post-intervention measures of muscular power (isokinetic dynamometry) and endurance (repetitions at 70% 1RM); Duration: 12 weeks; Design: Randomized, double-blind, matched for training volume and caloric intake.
Prospective Cohort Study of Protein Intake and Changes in Muscular Power and Endurance Over 1 Year in Older Men Engaging in Regular Resistance Training
Population: Healthy older men (≥60 years) self-reporting regular resistance training; Exposure: Baseline and monthly protein intake measured via dietary logs; Outcome: Annual changes in muscular power and endurance assessed by standardized tests; Duration: 12 months; Design: Prospective, adjusted for training volume, age, and baseline fitness.
Cross-Sectional Analysis of Protein Intake and Muscular Power/Endurance in Older Men Engaging in Resistance Training
Population: Healthy older men (≥60 years) currently performing resistance training; Exposure: Single measurement of daily protein intake; Outcome: Single measurement of muscular power and endurance; Duration: Single time point; Design: Population-based survey with physical performance testing.
Case Report of Two Older Men with Identical Resistance Training Volume but Differing Protein Intakes (1.6 vs. 0.8 g/kg/d) and Stable Muscular Power and Endurance
Population: Two individual cases of healthy older men performing identical resistance training; Exposure: One consuming 1.6 g/kg/d, one consuming 0.8 g/kg/d; Outcome: Parallel tracking of muscular power and endurance over time; Duration: 6 months; Design: Single-case observational report with no control group.