Muscle: Your Metabolic Powerhouse

Welcome to Week 1 of the Muscle Medicine series

Jun 06, 2025

When we think about metabolism, muscle isn’t usually the first organ that comes to mind. We’re more likely to think of the thyroid, the liver, or blood sugar levels. But what if one of the most powerful regulators of your metabolic health is something you can flex?

Muscle is not just about movement, strength, or aesthetics. It's a living, working organ that plays a central role in how your body processes energy, regulates blood sugar, balances hormones, and even manages inflammation. And right now, the science around it is evolving fast — and the hype is justified (ok well maybe all the commercial gain around it isn’t justified but you know what I mean!).

This month, we’re diving into Muscle Medicine: a guided series exploring how critical muscle health is to your overall well-being — and how you can harness it, no matter your age or fitness level. We’ll cover the physiology, the practical steps, the myths, and the mindset shifts. But first, let’s start with why this matters.

So you know what’s ahead, upcoming articles will focus on:

How to Build and Preserve Muscle Without the Gym
Practical guidance for resistance training at any level — especially for people who don’t identify as “fit.”
How to Eat for Strength: Supporting Muscle Through Nutrition
How food choices support muscle growth, repair, and maintenance — especially in midlife and beyond.
Muscle, Hormones, and Aging: What You’re Not Being Told
How hormones and muscle mass influence each other — and what that means in perimenopause, menopause, and beyond.
Bonus piece: Muscle Mindset: Shifting from Shrinking to Strengthening
(I can also mold this to your request!)

Muscle Is a Metabolic Organ

Most of us are taught to think of muscle as only mechanical — something that lifts, bends, and holds us upright. But from a medical and metabolic perspective, muscle is biologically active. It doesn’t just respond to what we do — it actually shapes how we function internally.

Here’s what muscle is doing behind the scenes:

It burns fuel — even at rest.
Unlike fat tissue, which stores energy, muscle tissue uses energy. That means the more muscle mass you have, the more calories your body burns throughout the day — even while sitting still.
It regulates blood sugar.
Muscle is the largest site for glucose disposal in the body. After you eat, it helps clear sugar from the bloodstream and stores it for future energy needs. If your muscle is underused or diminished, your ability to regulate blood sugar — and your sensitivity to insulin — takes a hit.
It communicates with the rest of your body.
Yes, muscle talks. It releases compounds called myokines — signaling molecules that influence inflammation, immunity, and even brain health. If any of you have read my book, Joy Is My Justice, I talk about these myokines, what scientists have dubbed ‘hope molecules,’ a term that makes me smile every single time! Some researchers now consider muscle an endocrine organ, right alongside the adrenal glands or pancreas.

This means when we strengthen muscle, we’re not just changing how we look — we’re changing how our body talks to itself.

Why You’re Hearing So Much About Muscle Right Now

If it feels like “muscle” is everywhere in health and wellness conversations lately, it’s because the science is finally catching up to what many in integrative and functional medicine have observed for years: muscle isn’t optional. It’s essential.

We’re shifting from weight loss to body composition.
The old health narrative focused on the scale — lose weight, cut calories, shrink down. But we now know that what you lose (muscle vs. fat) is just as important as how much. Building and preserving muscle is now seen as a key metric for long-term health.
Midlife muscle matters.
Muscle loss accelerates in perimenopause and andropause. As hormone levels shift, maintaining muscle becomes harder — and more important. This is especially relevant for women, whose metabolic health is tightly interwoven with muscle strength, hormone balance, and bone density.
Longevity research is dialing in.
New studies are linking muscle mass and strength with reduced risk of chronic disease, longer lifespan, and — crucially — better quality of life in older age. In short: strong muscles = longer healthspan.
Fitness culture is evolving.
There’s a growing shift from chasing thinness to pursuing strength. More people are discovering that muscle isn’t about aesthetics or ego — it’s about energy, mood, glucose control, and functional independence.

Muscle Loss Is Common — But Not Inevitable

Here’s the thing: if you’re not intentionally preserving or building muscle, chances are you’re losing it.

Starting as early as our 30s, we begin to experience sarcopenia — the natural, age-related decline in muscle mass and strength. This process accelerates over time, especially in the absence of resistance training, adequate nutrition, or restorative sleep. But here’s what’s often left unsaid: this isn’t just about getting weaker. It’s about getting sicker.

As muscle mass declines:

Metabolic rate slows.
With less active tissue, the body burns fewer calories at rest, making it easier to gain fat — especially visceral fat that increases disease risk.
Blood sugar becomes harder to regulate.
Muscle is one of the main places insulin does its job. Less muscle means more insulin resistance and higher blood glucose.
Fatigue and frailty increase.
Less strength means less energy and more risk of injury, falls, and loss of independence over time.

Modern life doesn’t help! Our bodies were designed to move and lift and carry — but we’ve engineered convenience into every corner of our days. Sitting is the norm. Have you heard the phrase, “Sitting is the new smoking”—it’s a real problem. Physical labor is outsourced. We’re told to eat less and exercise more, but not taught how to move in ways that build resilience.

The result? An epidemic of muscle loss — one that masquerades as “normal aging” or “slowing down” when it’s actually a warning sign.

The good news: muscle is incredibly responsive to intentional care, no matter your age or fitness level.

Reclaiming Your Metabolic Engine

If there’s one takeaway from today’s post, it’s this:

Muscle is not optional. It’s your metabolic engine, your glucose buffer, your anti-inflammatory ally — and your built-in health insurance.

This month, we’ll walk through how to protect and build that engine. I’ll break down the science, share practical strategies, and help you reframe muscle not as something reserved for athletes or fitness influencers, but as something essential for you — for your energy, your hormones, your longevity.

In the next article, we’ll look at how to start building or preserving muscle in a sustainable, realistic way — including how to do it even if you’ve never lifted a weight in your life.

For now, I invite you to simply notice:
💪🏽 Where in your life might your muscle need more attention — and where might it already be working hard for you?

Quick note: And somehow I forgot to send out a summary of takeaways from an amazing session for paid subscribers last Saturday on mental health. We only had a few people able to come so I chose not to record it for intimacy sake. I really dug in with the attendees on their mental health and how to practically implement some game changing practices. And we had a beautiful discussion with lots of practical takeaways so I will send out a summary, I promise!

I’m looking forward as always, hearing your questions and reflections in the comments. I want to hear what about this resonated, surprised or confirmed for you what you’ve been working on. As we go through the month, let’s support each other to find ways to integrate muscle medicine as a tool of longevity and power. And if you found this helpful, feel free to share it with someone who could use this empowered perspective on their health journey.

Your Integrative Physician | Tanmeet Sethi, MD

Discussion about this post