Among 6,249 US adults in NHANES (1999-2002), those in the highest protein quintile (>1.40 g/kg/day) had markedly lower odds of accelerated aging than those in the lowest (<=0.62 g/kg/day): OR 0.40 for short telomeres, 0.54 for PhenoAge, and 0.53 for the Klemera-Doubal Method. Higher intake also tracked with lower all-cause mortality, and biological-age measures partially mediated that link. Consistent with other analyses, the benefit appeared across several independent aging clocks rather than one metric. This is a preprint and has not been peer reviewed, so the numbers may shift. The finding fits a growing view that the old recommendation of 0.8 g/kg/day may be too low for older adults, whose muscle-preservation needs are higher. Still, the design limits what can be concluded. A single dietary recall per person is a noisy measure of habitual intake, and observational data cannot separate protein from the overall dietary pattern, income, or physical activity that accompany it. Protein source matters too: plant and animal protein often show opposite mortality signals, and the abstract does not say whether that was examined. Mediation analysis using cross-sectional clocks also cannot establish that slowed aging explains the survival benefit. For readers, the practical reading is modest: reaching roughly 1.2-1.4 g/kg/day from varied, minimally processed sources appears reasonable and unlikely to harm healthy adults, though people with kidney disease should consult a physician. Overall, this is confirmatory rather than paradigm-shifting, adding biological-aging endpoints to an already supportive literature, and it awaits trial-level evidence.