Building muscle for longevity | Dr Brad Schoenfeld and Alan Aragon

What It Covers

Brad Schoenfeld and Alan Aragon join The Proof to examine how skeletal muscle changes with age, why sarcopenia affects 10–20% of adults over 60, and what resistance training and protein intake strategies can meaningfully slow or reverse those losses — covering fiber types, anabolic resistance, protein dosing, recomposition, and GLP-1 drug considerations across nearly four hours.

Key Questions Answered

• •Sarcopenia timeline: Muscle loss begins around age 30 and accelerates progressively — roughly 0.5% annually from age 40, 1–1.5% from age 50, and approximately 3% per year from age 60 onward. Sedentary individuals compound this through inactivity-driven secondary sarcopenia. Resistance training is the only intervention shown to meaningfully counteract this decline; general daily activity, including walking and household tasks, produces some retention but insufficient protection against clinically significant muscle loss.
• •It's never too late to start: A 1990 study by Maria Fiatarone placed nonagenarians (average age 90) on a three-day-per-week leg extension protocol for eight weeks. Average strength increased 150%, functional capacity improved 50%, and three of ten participants regained the ability to walk without a cane. More recent meta-analyses confirm that adults aged 75 and older show effect sizes of approximately 1.0 standard deviation for strength and 0.3 for hypertrophy within 8–16 weeks of beginning resistance training.
• •Protein targets by population: For general adults seeking muscle preservation, target 1.6 grams of protein per kilogram of ideal or goal body weight daily. Lean, resistance-trained individuals in a sustained caloric deficit benefit from 2.4–3.2 grams per kilogram of body weight, per a forthcoming German RCT showing the 1.6g group lost over one kilogram of lean mass versus under 0.3 kilograms in higher-protein groups. Base calculations on ideal body weight, not actual weight, for overweight individuals.
• •Older adults need more protein per meal: Younger adults maximally stimulate muscle protein synthesis with roughly 20–25 grams of high-quality protein per meal. Older adults experiencing anabolic resistance — a blunted MPS response driven by reduced microvascular perfusion, lower satellite cell activity, and chronic inflammation — may require 35–40 grams per meal to achieve a comparable response. This is especially relevant for plant-based eaters, who may need leucine supplementation or higher total protein to compensate for lower leucine density per gram.
• •Protein timing is a distant secondary priority: A 2013 meta-analysis by Schoenfeld and Aragon found no meaningful difference in muscle size or strength gains between protein-timed and protein-neglected conditions when total daily intake reached approximately 1.6–1.7 grams per kilogram. Pre- versus post-exercise protein produced equivalent results. Intermittent fasting studies (six-hour feeding windows) similarly show minimal hypertrophy differences. Prioritize hitting total daily protein first; distribution across three or more protein-rich meals is a secondary optimization, relevant mainly for competitive bodybuilders.
• •Type II fiber loss drives falls and metabolic decline: Age-related apoptosis preferentially targets type II (fast-twitch) muscle fibers, reducing both maximal strength and power output — the capacity to generate force rapidly. Power specifically determines fall-recovery ability; without it, strength alone cannot prevent injury. Hip fractures carry roughly a 50% rate of permanent functional impairment. Training for power requires 40–60% of one-rep maximum moved at maximal speed, distinct from conventional strength training at moderate-to-heavy loads, and both modalities should be incorporated.
• •GLP-1 drugs require deliberate muscle protection: Approximately 30 million Americans currently use GLP-1 receptor agonists. The appetite suppression these drugs produce frequently causes users to under-consume both total calories and protein, accelerating lean mass loss alongside fat loss. Resistance training and deliberate protein tracking — targeting at least 1.6 grams per kilogram of goal body weight — are necessary co-interventions. Without them, users risk sarcopenic outcomes despite achieving fat loss, undermining the metabolic and functional benefits the weight loss was intended to produce.