If I could persuade every patient over fifty of just one thing, it might be this: the muscle you carry is not vanity, it is infrastructure. It is how you stay independent, how you recover from illness and surgery, how you avoid the fall that too often begins a long decline. In wound care I see the downstream version of muscle loss constantly — frail patients who heal slowly because they simply do not have the reserves of protein and strength that repair demands. To heal the hole in the patient, you have to take care of the whole patient, and a great deal of the "whole patient" is, quite literally, muscle.

The good news, and the reason I am optimistic, is that this is one of the most fixable problems in all of aging.

The slow leak nobody warns you about

Starting somewhere in our thirties and accelerating later, we lose muscle mass and strength gradually — a process that, when it becomes significant, clinicians call sarcopenia. It is now formally recognized as a muscle disease, with strength (not just size) at the center of how it is defined and diagnosed.1 That shift in emphasis matters: it is the force your muscle can produce, and the function that follows, that predicts whether you stay vigorous or become fragile.

Here is the part that connects to a theme from earlier letters. Aging muscle does not just shrink — it changes character. Healthy, contractile tissue is gradually infiltrated and replaced by fat and fibrous, scar-like tissue. That is fibrosis again, the same drift from vital tissue toward inert tissue that I keep coming back to, showing up here in the very engine of your mobility. Left unaddressed, the leak compounds quietly for decades.

Anabolic resistance: why older muscle is harder to feed

There is a specific reason this gets harder with age, and it is worth understanding because it changes what you should do. Older muscle becomes less responsive to the usual signals that tell it to build — a phenomenon researchers call anabolic resistance.2 A serving of protein that would comfortably trigger muscle-building in a younger person produces a blunted response in an older one. The machinery still works; it just needs a stronger push.

That single fact reframes the standard advice. The old guidance to eat less as we age is, for muscle, almost exactly backwards.

What actually works: protein, and a real reason to lift

Two interventions have the evidence behind them, and they work best together.

Eat enough protein, and spread it out. An international expert group (PROT-AGE) concluded that healthy older adults need more dietary protein than the old standard — on the order of 1.0 to 1.2 grams per kilogram of body weight per day, and more during illness or recovery — to maintain muscle and function.3 To overcome anabolic resistance, distribution matters as much as total: a meaningful dose of protein at each meal does more than loading it all at dinner.

Lift something heavy enough to matter. Resistance training is the non-negotiable partner to protein. A meta-analysis of resistance-exercise trials in older adults found clear, substantial gains in strength — older muscle responds robustly to progressive resistance training, often more than people expect.4 This does not require a fancy gym. It requires resistance that genuinely challenges the muscle, applied consistently, and progressed over time.

What to be skeptical of

In keeping with the last letter — on reading studies without getting fooled — let me flag what does not do the job. The supplement aisle is full of single compounds promising to rebuild muscle on their own. Isolated leucine is a good example: despite a sound theoretical rationale, long-term leucine supplementation did not increase muscle mass or strength in healthy older men in a controlled trial.5 The lesson repeats across this whole field: there is rarely a powder that substitutes for the food and the work. The fundamentals are unglamorous, affordable, and effective — which is exactly why they are so widely skipped.

Functional age is the number that matters

I would rather know how much you can carry, how quickly you can rise from a chair, and how steadily you can walk than know the number on your birth certificate. Those functional measures — not the calendar — track most closely with how the rest of your life will go. And unlike your birthday, they are measures you can move. I have watched patients in their seventies and eighties add strength and steadiness that genuinely changed their trajectory. It is rarely too late to start, and the earlier you start, the more you keep.

So if you take one thing from this letter, make it a plan you can begin this week: get enough protein at each meal, and start challenging your muscles against real resistance. Then take it back to your own physician — especially if you have kidney disease or other conditions that affect protein needs — and build it into the rest of your care. Muscle is the most negotiable part of aging. Negotiate hard.

Dr. Marc Gitterle is a physician in wound care and hyperbaric medicine and the author of Growing Young: A Doctor's Guide to the NEW Anti-Aging. General education, not individual medical advice; protein targets should be individualized with your clinician if you have kidney disease or other relevant conditions.

References

  1. Cruz-Jentoft AJ, Bahat G, Bauer J, et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing. 2019;48(1):16–31. https://doi.org/10.1093/ageing/afy169
  2. Breen L, Phillips SM. Skeletal muscle protein metabolism in the elderly: interventions to counteract the 'anabolic resistance' of ageing. Nutr Metab (Lond). 2011;8:68. https://doi.org/10.1186/1743-7075-8-68
  3. Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people (PROT-AGE Study Group). J Am Med Dir Assoc. 2013;14(8):542–559. https://doi.org/10.1016/j.jamda.2013.05.021
  4. Peterson MD, Rhea MR, Sen A, Gordon PM. Resistance exercise for muscular strength in older adults: a meta-analysis. Ageing Res Rev. 2010;9(3):226–237. https://doi.org/10.1016/j.arr.2010.03.004
  5. Verhoeven S, Vanschoonbeek K, Verdijk LB, et al. Long-term leucine supplementation does not increase muscle mass or strength in healthy elderly men. Am J Clin Nutr. 2009;89(5):1468–1475. https://doi.org/10.3945/ajcn.2008.26668

Sources via PubMed.