Approximate dose-response bands. Individual response varies — these are starting points, not prescriptions.
Muscle loss, slow wound healing, immune dysfunction.
RDA (~50 g) is a survival floor, not optimum. Active adults often need 1.2–2.0 g/kg.
FDA DV met. Supports basic enzymatic and structural needs.
Higher intake supports muscle protein synthesis in training adults and older people.
Past the point where extra intake typically helps. Evidence for further benefit is thin.
You're at 0% of your protein target. The biggest single-serving sources to top it off:
Macronutrient providing the 20 amino acids required for tissue synthesis, enzymes, hormones, immune molecules, and signalling. Adequate protein supports muscle maintenance, immune function, and satiety — especially relevant in aging (sarcopenia prevention requires 1.0–1.2 g/kg, well above the 0.8 RDA).
Dietary protein is hydrolysed to amino acids and small peptides. Leucine triggers mTORC1 signalling that initiates muscle protein synthesis — a ~3 g leucine 'threshold' per meal (~25–30 g high-quality protein) maximises MPS response in older adults. Protein turnover is continuous (~250 g/day in adults); inadequate intake forces net negative balance and tissue loss.
Rare in calorie-replete populations but functional inadequacy is common in older adults (sub-RDA + reduced anabolic response = ongoing muscle loss). Kwashiorkor (protein-calorie malnutrition) is a global pediatric issue.
Tolerated to ~3.5 g/kg/day in healthy kidneys. Older 'high protein causes kidney damage' claim is outdated — only relevant in pre-existing renal disease. Some hydration adjustment needed for nitrogen excretion.
Whole-food protein is the best baseline. Whey isolate has the highest leucine content per gram (best muscle protein synthesis trigger). Casein digests slowly and is good before sleep. Plant blends (pea + rice) provide complete amino acid coverage. Soy is a complete protein on its own.
DIAAS / PDCAAS scores: whey ~1.09, milk ~1.0, egg ~1.0, soy ~0.91, beef ~0.92, pea ~0.65, wheat ~0.42. Older adults need higher per-meal doses (~0.4 g/kg per meal vs ~0.25 g/kg in young adults) due to anabolic resistance.
U-shaped relationship: low intake drives sarcopenia and fall/fracture risk in older adults — the dominant cost. Very high animal protein has weak association with cardiometabolic risk in some cohorts (mTOR signalling and IGF-1) but the benefit of preventing sarcopenia outweighs in most older adults. Spread intake across meals (~3 × 30 g) is more anabolic than back-loading.
Amino acids for muscle protein synthesis, enzymes, hormones.
The mechanisms and systems this nutrient feeds. Click any to drill into what runs on it.
★ = load-bearing / primary cofactor. Track these in My Journey.