The FAXAge trial will randomize 240 healthy adults over 65 into four groups—exercise alone, time-restricted feeding alone, both interventions combined, or control—to measure effects on DNA methylation clocks over 52 weeks with follow-ups extending to 10 years. The study represents the first large-scale attempt to rigorously test whether combining two promising longevity interventions produces synergistic anti-aging effects. While exercise consistently shows protective benefits against age-related diseases, time-restricted feeding has primarily demonstrated metabolic improvements in animal studies with limited human aging data. The comprehensive approach measuring DNA methylation age, transcriptomics, metabolomics, inflammation, microbiome, and cognitive function could provide definitive evidence about practical anti-aging interventions accessible to most adults. However, this is currently just a study protocol preprint awaiting peer review, meaning the actual trial results remain years away. The ambitious 10-year follow-up timeline is scientifically valuable but practically challenging for participant retention. If successful, this could be paradigm-shifting research providing the first robust evidence that lifestyle interventions can measurably slow biological aging in humans, potentially revolutionizing preventive medicine approaches for healthy aging.