Gabrielle Lyon is the physician who keeps repeating a sentence the rest of medicine underweights: aging looks a lot like disappearing muscle. She is a DO, trained in geriatrics and nutritional sciences, and the book is Forever Strong. “Muscle-centric medicine” is the label. Under it is a simple bet. Skeletal muscle is the organ of longevity you can still train at 45, 55, 70. Lose it and glucose handling, bone, fall risk, and independence go with it.
Protein is the dietary hill she will die on. Higher than the dusty RDA. Distributed across the day. Anchored to actual lifting, not to a smoothie identity. If Attia talks about the centenarian decathlon, Lyon talks about the tissue that lets you show up for it. That is why she belongs on muscular fitness and next to resistance training.
The female physiology piece is doing real work on this site. A lot of longevity Twitter still writes as if everyone were a 35-year-old man with a garage gym. Lyon talks about perimenopause, protein needs that go up as anabolic resistance sets in, and why “eat less and cardio more” is how people get skinny-fat and frail.
She is a clinician with a brand. The protein targets are higher than some dietitians like. If your kidneys are actually impaired, that is a labs conversation. For a healthy adult who lifts, the bigger error in 2026 is still too little protein and too little iron on the bar, not too much chicken.