TL;DR — The PROT-AGE Study Group — an international consensus of geriatricians and nutrition researchers — recommends that healthy adults over 65 consume 1.0–1.2 g of protein per kg of body weight per day, higher than the standard adult RDA. Evidence suggests this threshold, combined with resistance training, helps preserve muscle mass and function with aging and may lower the risk of sarcopenia-related outcomes such as falls and disability.
Sarcopenia is the progressive, age-related loss of skeletal muscle mass, strength, and function. It is distinct from ordinary weight loss — it specifically affects muscle tissue and is strongly associated with:
Muscle loss typically begins in the fourth decade of life and accelerates after 60. The underlying mechanisms are multifactorial and connect to several hallmarks of aging, including mitochondrial dysfunction and altered nutrient-sensing [1].
→ For the broader framework, see our pillar: The Science of Longevity.
In 2013, the PROT-AGE Study Group published a consensus position paper in the Journal of the American Medical Directors Association [2]. Their recommendations for healthy older adults include:
These numbers are higher than the standard adult RDA of 0.8 g/kg/day, which PROT-AGE and subsequent reviews consider inadequate for optimal muscle protein synthesis in aging adults.
A common oversight in protein intake is focusing only on daily total. Research on muscle protein synthesis suggests that the body's ability to synthesize new muscle protein in response to a meal plateaus at around 25–40 g of high-quality protein, depending on body size and source. This has two practical implications:
The practical takeaway: distribute protein across 3–4 meals, each containing roughly 25–40 g of high-quality protein.
"Protein quality" refers to a protein's essential amino acid profile — particularly its leucine content, which is a key trigger of muscle protein synthesis. High-quality sources include:
Plant-based diets can meet protein targets but generally require higher total intake and deliberate variety to match the amino acid profile of animal sources.
Protein intake works synergistically with mechanical loading — in other words, resistance training. The PROT-AGE paper and subsequent literature consistently emphasize that dietary protein and resistance exercise together produce substantially greater benefits for muscle preservation than either alone.
Aerobic training also plays a role, both through its systemic benefits and through its contribution to cardiorespiratory fitness, which is independently associated with longevity.
→ Read more: Zone 2 Cardio and Mitochondrial Health → Read more: VO2 Max as a Longevity Biomarker
A straightforward approach:
A 70 kg adult would target roughly 70–84 g per day, distributed as ~20–30 g at breakfast, lunch, and dinner.
Muscle protein synthesis is regulated in part by growth hormone and other hormones with strong circadian rhythms. Chronic sleep restriction impairs muscle protein synthesis and the anabolic response to both resistance training and protein intake.
→ Read more: Sleep Architecture and Biological Aging
Is the RDA for protein (0.8 g/kg/day) enough for older adults? The PROT-AGE Study Group and multiple subsequent reviews consider the standard RDA inadequate for optimal muscle protein synthesis in adults over 65. They recommend 1.0–1.2 g/kg/day for healthy older adults [2].
Can I get enough protein from a plant-based diet? Yes, with attention to variety and total intake. Plant proteins generally have lower leucine content per gram than animal proteins, so plant-based eaters may benefit from slightly higher total intake.
Does high protein intake damage the kidneys? In adults with normal kidney function, there is no strong evidence that moderately higher protein intake causes kidney damage. Adults with existing chronic kidney disease should work with a clinician.
What counts as a high-quality protein source? High-quality sources are those with a complete essential amino acid profile and good leucine content, including animal proteins, eggs, dairy, soy, and whey isolate.
Charles Kamen, MD earned his medical degree from Albert Einstein College of Medicine and completed his internal medicine internship at Yale-New Haven Hospital, followed by a neurology residency at Loma Linda University. He is board-certified by the American Board of Psychiatry and Neurology.
This article is for educational purposes and does not constitute medical advice. Individuals with chronic health conditions should consult a qualified clinician before making significant dietary changes.