Data
Nutrition & body-composition data
Key statistics on protein, fat loss, sleep, hormones and metabolism, each with its source study. Free to cite and link to this page.
Protein & muscle
threshold where muscle gain stops increasing with more protein.
Source: Morton et al. 2018 (meta-análisis, 49 estudios)
protein per meal, across 3–5 servings, to maximize synthesis.
Source: Schoenfeld & Aragon 2018
real length of the post-workout "anabolic window" (not 30 min).
Source: Aragon & Schoenfeld 2013
Fat loss
more muscle preserved losing weight slowly (0.7%/wk) vs fast (1.4%/wk).
Source: Garthe et al. 2011
drop in testosterone when dietary fat falls below 20% of calories.
Source: Whittaker & Harris 2022
Sleep
less fat lost sleeping 5.5 h vs 8.5 h in a deficit (muscle is lost instead).
Source: Nedeltcheva et al. 2010
drop in testosterone after 1 week sleeping just 5 h.
Source: Leproult & Van Cauter 2011
extra calories eaten per day after one night of poor sleep.
Source: Greer et al. 2013
Hormones & metabolism
rise in testosterone with vitamin D (3,332 IU/day, 1 year) in deficient men.
Source: Pilz et al. 2011
drop in insulin sensitivity after ONE night of partial sleep.
Source: Donga et al. 2010
reduction in glucose spike when eating veg & protein before carbs.
Source: Shukla et al. 2015
Cold, heat & longevity
all-cause mortality with sauna 4–7×/week (20-year follow-up).
Source: Laukkanen et al. 2015 (JAMA Intern Med)
increase in dopamine after cold-water immersion.
Source: Šrámek et al. 2000