Why Muscle Matters More As You Age
There's a lot marketed to us about changing our bodies — cosmetic procedures, supplements, medications promising fast results. Some of these can shift what you see on a scale. But none of them, on their own, can build or preserve the one tissue your long-term metabolic health actually depends on: muscle.
As naturopathic doctors, we're less interested in any single number and more interested in how well your body is functioning — how it moves, regulates blood sugar, recovers, and carries you through daily life. Muscle is central to all of it, at every age and every size.
Why This Matters More As You Get Older
Starting in your 30s, most adults lose roughly 3–5% of their muscle mass per decade — a process called sarcopenia — and that rate accelerates after age 60.¹ ² By some estimates, 5–13% of adults aged 60–70 are affected by clinically significant sarcopenia, rising to as high as 50% in adults over 80.³
This isn't a cosmetic concern. Muscle is metabolically active tissue: it's one of the body's primary sites for glucose disposal, meaning the more lean muscle you carry, the better your insulin sensitivity and blood sugar regulation tend to be.³
Metabolic health and body weight are related, but they aren't the same thing, and they don't move in lockstep. Two people can weigh the same amount and have very different amounts of muscle and very different metabolic function — and the same is true for one person over time, regardless of whether their weight changes at all. This is a core piece of how we think about health from a naturopathic lens: the scale is one data point among many, not a stand-in for how well your body is working.
The Part Nothing Else Can Replace
Here's what no medication, procedure, or supplement can do for you: stimulate your muscles to grow stronger. That adaptation happens only through resistance — your body responding to a real physical demand, placed on it repeatedly, over time. It's one of the clearest examples of the body's own capacity to adapt and rebuild when given the right input, which is very much the foundation naturopathic medicine works from.
This is good news. It means one of the most powerful tools for long-term metabolic resilience is fully within your control, independent of body size or any particular goal. Strength training:
Improves insulin sensitivity independent of weight change
Preserves and builds the lean mass that keeps your metabolism active
Supports bone density, balance, and functional independence — all things that compound in importance with age
Helps protect against the natural muscle loss that comes with aging, and with rapid changes in body weight in either direction
That last point matters regardless of why someone's weight is changing. Whether it's from diet changes, shifts in activity, illness, or a prescribed medication, rapid weight loss of any kind can come at the cost of lean mass if resistance training and adequate protein intake aren't part of the picture.⁴
This Isn't Just for Athletes
It's easy to hear "strength training" and picture gym-goers chasing a certain look. But the real stakes are much more universal: the strength to carry groceries, get up off the floor, climb stairs without hesitation, or catch yourself if you trip. These are the everyday markers of independence, and they rely directly on the muscle you have. This matters for every person, regardless of current fitness level, age, or body size — the earlier you build that reserve, the more of it you have to draw on later.
What This Means If You're on a GLP-1
Many of our patients are on GLP-1 medications, for a range of reasons and health goals. Whatever led you there, it's worth understanding what these medications can and can't do for your body composition — so you can support your body well while you're on them.
Research has consistently shown that a meaningful share of weight lost on these medications is lean mass, not only fat. In the STEP 1 trial, lean mass accounted for roughly 45% of total weight lost on semaglutide; in SURMOUNT-1, lean mass made up about 34% of weight lost on tirzepatide.⁴ Other clinical reviews place the range at roughly 25–40% across GLP-1 therapies.⁵
This isn't a reason to avoid these medications if they're part of your care plan — it's a reason to pair them intentionally with resistance training and adequate protein intake, so your body holds onto the muscle it needs to function well, no matter what the scale does.⁶
What We Recommend
Whatever your goals — whether or not weight change is part of them, and whether or not you're on a GLP-1 — our guidance is consistent: prioritize regular resistance training and sufficient protein intake as a foundation, not an afterthought. In naturopathic medicine, we look for the interventions that support the body's own systems rather than override them — and building and maintaining muscle is one of the clearest examples of that principle in action.
Building muscle is one of the few things in health that genuinely can't be outsourced. The effort is the mechanism. And it's available to you at any age, at any size, and at any stage of your health journey.
Ready to explore how strength training fits your plan? We're happy to discuss it at your next visit.
This content is for educational purposes only and is not intended as medical advice. Please consult a qualified healthcare provider before making any changes to your treatment or lifestyle.
References
Preserve your muscle mass. Harvard Health Publishing, Harvard Medical School. 2024. https://www.health.harvard.edu/staying-healthy/preserve-your-muscle-mass
Sarcopenia. Office on Women's Health, U.S. Department of Health and Human Services. 2024. https://womenshealth.gov/sarcopenia
Cruz-Jentoft AJ, et al. An overview of sarcopenia: facts and numbers on prevalence and clinical impact. European Geriatric Medicine, via PMC. 2010. https://pmc.ncbi.nlm.nih.gov/articles/PMC3060646/
Neeland IJ, et al. Muscle Mass and Glucagon-Like Peptide-1 Receptor Agonists: Adaptive or Maladaptive Response to Weight Loss? Circulation, American Heart Association Journals. 2024. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.124.067676
