369 ‒ Rethinking protein needs for muscle and longevity, and the benefits of creatine & sauna use

KEYPOINTS

• 01

  The 0.8 g/kg protein RDA is a minimum based on flawed methods; the true floor is closer to 1.2 g/kg.

  The RDA came from nitrogen-balance studies that suffer from incomplete urine collection, nitrogen lost by other routes, and varying nitrogen-to-protein ratios across foods. Stable-isotope studies using 13C-phenylalanine oxidation put the requirement 30–50% higher, around 1.2 g/kg. Surveys suggest adults average about 0.9 g/kg (men) and 0.8 (women)—at the flawed RDA, not the corrected floor.

• 02

  There's no amino-acid reserve except muscle.

  Fat can be stored almost without limit and glycogen buffers carbohydrate, but skeletal muscle is the only amino-acid 'tank.' Falling short means breaking down muscle immediately—what Attia calls an unforced error.

• 03

  Anabolic resistance is driven more by inactivity than by age.

  Given the same protein dose, adults 65+ get about half the muscle protein synthesis of young adults, so they need roughly double the protein for the same response. But older people who resistance-train respond like young people. Luc van Loon's one-leg-cast study showed the immobilised leg became anabolically resistant while the trained leg didn't. Only about 32% of adults, and 22% of older adults, resistance-train.

• 04

  Sarcopenia arrives in steps, not as a smooth slope.

  Population curves average out what individuals experience: a surgery, fall or flu causes weeks of immobility and muscle loss that older people never fully regain. Repeated hits push people past a 'disability threshold.' Attia says frailty, alongside cognition, largely determines the quality of your last decade, so build muscle 'headroom' at 40–60.

• 05

  Above 1.2 g/kg, more protein still adds lean mass, with diminishing returns.

  Stu Phillips' meta-analysis of about 49 resistance-training trials found adding protein up to roughly 1.6 g/kg gave about 27% more lean-mass gain and 10% more strength than training alone. Benefits taper toward ~2.2 g/kg—Phillips' 'wringing a washcloth' analogy. Intakes around 3 g/kg add little, but neither guest knows of human data showing harm in healthy people.

• 06

  Attia's rule: aim for 2 g/kg so your bad days still land at 1.6.

  Real life means missed meals and pasta nights. Because the downside of falling short is larger than the upside of overshooting, aiming at 1.6 means bad days fall to 1.2 and aren't made up. He notes David Allison's public call for harm data has met 'crickets.' The worst result he's seen is that high-protein IV nutrition in ICU patients showed no benefit—not harm.

• 07

  Use target body weight, not current weight, if you carry a lot of excess fat.

  A 300 lb person whose healthy weight is around 220 should calculate from 220. Higher needs apply in calorie deficits and body recomposition (≥2.2 g/kg), heavy training, pregnancy and adolescence.

• 08

  The mTOR fear misreads where leucine goes in active people.

  Only calorie restriction and rapamycin extend life in yeast, worms, flies and mice, both by lowering mTOR, and leucine strongly activates mTOR. But exercise increases leucine transporters so amino acids go into muscle, where you want mTOR on. Lab mice are sedentary, warm, fed freely, and never face catabolic illness. Attia likens mTOR to inflammation or cortisol: on when needed, quiet otherwise.

• 09

  Creatine: 5 g/day saturates muscle; 10 g/day may be needed to raise brain levels.

  The body makes about 1–2 g a day and meat supplies more; vegetarians benefit most from supplementing. About 5 g a day saturates muscle in 3–4 weeks without loading. It works by recycling ATP so you can do more reps—it doesn't build muscle for a couch potato. Patrick cites a German dose-response study where brain creatine rose only at about 10 g, because muscles take up the first 5 g. Studies using 5 g may wrongly show no brain effect.

• 10

  Creatine's cognitive benefits show up mainly under stress.

  Gains appear with sleep deprivation, exams, aging or neurodegeneration—the brain uses about 20% of calories at under 2% of body weight. Small studies show sleep-deprived subjects given about 20–25 g kept, or even beat, baseline processing speed. A pilot gave 20 g in Alzheimer's patients with improved cognition. Patrick says the literature is still small and you can't hang your hat on it.