The Case for Muscle
When people talk about health, they talk about cardio. They talk about BMI and weight loss. They talk about eating vegetables and getting steps in and doing their couch-to-5k. The fitness industry has spent decades equating health with being smaller, lighter, less muscular.
This is a significant mistake.
Muscle mass is the single most underrated predictor of long-term health, resilience, and longevity. Not the biggest factor. Not the only factor. But significantly underrated. More important than most people realise, and worth investing in far earlier than most people do.
The conversation about health has been too focused on cardio and weight loss and not enough on building and maintaining muscle tissue. And this has real consequences, particularly as people get older.
What We Get Wrong About Health
The standard health narrative is that you need to be thin. Or at least, not overweight according to BMI. So people focus on weight loss. They do cardio. They cut calories. They try to become lighter.
There's nothing wrong with that goal if someone is genuinely overweight and sedentary. But the focus on weight loss above all else has created a problem. People are optimising for becoming lighter, not for becoming healthier.
Two people can weigh the same and have completely different health outcomes. One might be 82kg of mostly muscle with low body fat. The other might be 82kg of mostly fat with very little muscle. By BMI standards, they're equivalent. By any meaningful health metric, they're not remotely similar.
The person with muscle has:
Better metabolic health. Muscle tissue is metabolically active. It consumes energy at rest. The person with more muscle has a higher basal metabolic rate. They can eat more without gaining fat. Their body handles carbohydrates better because muscle is an enormous glucose sink. When you eat carbs, they preferentially go to muscle tissue if you have plenty of it.
Better insulin sensitivity. Muscle tissue is extraordinarily sensitive to insulin. When glucose enters your bloodstream, muscle cells grab it and store it. This means your pancreas doesn't have to work as hard. Your insulin levels stay lower. Your risk of type 2 diabetes decreases. Your body ages better.
Better bone density. Weight-bearing activity, particularly resistance training, builds bone density. Muscle tissue pulling on bone stimulates bone remodelling and strengthening. This matters enormously as you age. Osteoporosis is a real health risk, particularly for women, and the single best defence against it is muscle mass and resistance training.
Better movement quality. Muscle tissue enables movement. Strength enables resilience. The person who can lift 90kg can pick up their grandchild without injury. The person who can't is vulnerable to injury from normal daily activities.
Better longevity. This is the big one. Low muscle mass is associated with higher mortality rates across the board. Not because muscle is magic, but because muscle reflects overall resilience, capacity, and health. As you age, sarcopenia (age-related muscle loss) is one of the biggest predictors of illness, frailty, and death. The person who maintained muscle mass in their 30s and 40s is far less likely to experience catastrophic decline in their 60s and 70s.
None of this requires being a bodybuilder. It doesn't require being huge. It just requires having enough muscle tissue to support metabolic health, functional capacity, and physiological resilience.
The Metabolic Cost of Muscle
Let me be direct: if your goal is sustainable weight management, building muscle is genuinely one of the best approaches.
A kilogram of muscle tissue burns roughly thirteen calories a day at rest. A kilogram of fat tissue burns roughly four. This doesn't sound like much until you consider the time horizon.
Imagine you spend a year building muscle. You gain two kilograms of muscle tissue. That's twenty-six extra calories burned per day, just from having that tissue. Over a year, that's roughly 9,500 calories. That's over a kilogram of fat that your body burns automatically, just because you maintained muscle.
Now scale that over five years. Ten years. The person who built muscle in their 30s and maintained it into their 40s is burning significantly more calories at rest. They don't need to exercise as much to maintain their weight. They can eat slightly more and stay the same weight. They're not in a constant state of dietary restriction.
Compare this to the person who tried to lose weight through cardio alone, didn't build muscle, and now has a low metabolic rate. They're constantly fighting their biology. They need more and more exercise to maintain their weight. If they eat normally, they gain fat. They're in a biological hole that gets deeper over time.
Muscle tissue is your metabolic currency. The more you have, the more you can eat, the less you need to exercise, the easier weight management becomes. This is one of the most underrated benefits of building muscle.
The Protective Effect Against Decline
Here's something I think about constantly, particularly with clients in their 40s and 50s: what happens when you can't exercise anymore?
It's not a morbid thought. It's practical. Everyone experiences times when illness, injury, or life circumstances prevent them from training for extended periods. An ACL tear. Recovery from surgery. A demanding business period. An illness.
When you stop training, you lose muscle mass. This is called deconditioning. How much you lose depends on how much you had to begin with.
The person who had built significant muscle mass over years has a reserve. If they can't train for two months and lose 10% of their muscle mass, they still have 90% left. They can rebuild relatively quickly once they're able to train again.
The person who had minimal muscle mass to begin with loses the same absolute amount but has nothing in reserve. They're now genuinely weak. Rebuilding takes much longer. If this happens multiple times, the cumulative effect is a slow decline into real frailty.
This is part of why sarcopenia is so damaging. In your 70s and 80s, you lose muscle mass naturally just from aging. The person who built muscle in their 40s and 50s still has a reserve to draw on. The person who didn't is vulnerable to rapid decline.
Building muscle when you're young, when you have hormones on your side, when you have the time to do it, is like buying insurance. It's an investment in your capacity and resilience for decades to come.
Why Building Muscle Matters for Your Brain
This is less discussed but genuinely important. Muscle tissue communicates with your brain through a variety of signalling molecules. Exercise stimulates the production of brain-derived neurotrophic factor (BDNF), which is involved in neuroplasticity, learning, and cognitive health.
The person who maintains muscle and continues to challenge their body physically maintains better cognitive function as they age. They're stimulating their nervous system. They're maintaining neuroplasticity. They're providing their body with the signal that it needs to remain functional and adaptable.
There's a reason that strength training is increasingly recommended for brain health, for depression, for anxiety. It's not just about endorphins. It's about sending your body the signal that it needs to remain capable and strong.
The Asymmetry of Building and Losing
Here's something important: building muscle is slow. Losing it is fast.
It takes years to build significant muscle mass. Six months of consistent training might get you two kilograms of muscle. A decade might get you fifteen to twenty kilograms if you're disciplined.
But losing it can happen in weeks. Two weeks of inactivity and you've lost a noticeable amount. Two months and the loss is substantial. This asymmetry is important to understand.
It means that building muscle needs to be a priority now, not something you'll do later when you have time. Because you probably won't have significantly more time later. Life gets busier. Work demands increase. You'll be lucky to maintain consistency, let alone build.
If you're in your 20s, 30s, or 40s and you're reading this, the time to build muscle is now. Not when you retire. Not when life slows down. Now. Because the person who invests in muscle mass now has a massive advantage for decades to come.
It's Not About Aesthetics
I want to be clear: this argument for muscle isn't about looking good, though that's a nice side effect. This is about long-term health, independence, resilience, and longevity.
It's about being seventy years old and being able to get out of a chair without help. It's about being able to carry groceries up the stairs. It's about being able to play with your grandchildren without feeling fragile.
It's about not experiencing the rapid decline that happens to people who reach their 60s with no muscle mass. Where suddenly they're frail, they fall easily, they break bones, and their independence evaporates.
The choice to build muscle in your 30s is a choice for a better life in your 70s. It's that straightforward.
How Much Is Enough?
You don't need to be huge. You don't need to be a competitive athlete. You just need enough muscle mass to support metabolic health, functional capacity, and resilience.
For most people, this means training for strength two to four times per week. It means doing compound movements. It means eating enough protein to support muscle tissue. It means doing this consistently, not in three-month bursts.
The person who trains three times a week for ten years and builds fifteen kilograms of muscle mass has made one of the best investments in their health. They'll be stronger, healthier, more resilient, and more likely to live a long life with genuine quality and independence.
That's the case for muscle. Not for vanity. For health. For function. For longevity. For the version of yourself you want to be at seventy.
← Back to Journal