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My Performance Edge: Week 16. Lose Weight. But Protect the Muscle that Protects You – Kevin Kearns

August 22, 2026/Kevin Kearns

by Kevin Kearns, contributing writer on fitness and exercise

Why Muscle May Be One of Your Most Important Longevity Organs — Especially in the GLP-1 Era

For decades, we’ve been taught to judge health and weight loss by one number:

The scale.

Lose 10 pounds? Success.

Lose 30 pounds? Even better.

But there’s a problem with that thinking.

What exactly did you lose?

Fat?

Water?

Muscle?

Because those are very different outcomes.

After more than three decades working in strength, conditioning, martial arts and human performance, I don’t look at muscle simply as something that makes you stronger or look better.

Muscle is metabolically active tissue and one of the most valuable physical assets you have as you age.

It helps regulate glucose.

It influences metabolism.

It communicates with other tissues.

It supports your bones.

It protects your ability to move.

And ultimately, it helps determine whether your later years are spent merely living longer — or actually remaining capable.

The Muscle Loss Nobody Notices

One of the realities of aging is sarcopenia — the progressive loss of muscle mass, strength and physical function.

It usually doesn’t happen overnight.

That’s what makes it dangerous.

You lose a little strength.

You move a little less.

Getting off the floor becomes harder.

Stairs become more challenging.

Balance begins changing.

Eventually, what gets dismissed as “just getting older” can become a significant loss of physical capacity and independence.

And inactivity accelerates the problem.

That’s one reason resistance training becomes more important as we age — not less.

Your Muscles Actually Talk

Skeletal muscle isn’t simply sitting there waiting for you to use it.

When muscles contract during exercise, they release signaling molecules known as myokines, along with other exercise-associated molecules sometimes described as exerkines.

These signals communicate with other tissues and are being studied for their roles in:

Metabolism
Glucose regulation
Inflammation
Fat metabolism
Cardiovascular health
Brain function
Muscle repair and regeneration

Think about what that means.

Every time you train, you’re not simply burning calories. You’re sending biological signals throughout your body.

That’s one reason I’ve said for decades:

Exercise is medicine.

Muscle Is a Metabolic Reserve

Skeletal muscle also plays an enormous role in glucose disposal and metabolic health.

Lose substantial muscle while simultaneously becoming less active and accumulating visceral fat, and you’ve created a very different metabolic environment.

So preserving muscle isn’t about becoming a bodybuilder.

It’s about maintaining the physical reserve necessary to live your life.

Carrying groceries.

Climbing stairs.

Getting yourself off the floor.

Traveling.

Playing with your children or grandchildren.

Maintaining balance.

Protecting yourself.

Continuing to do the things that make you you.

Now Add the GLP-1 Revolution

This conversation has become even more important with the explosive growth of GLP-1–based weight-loss therapies.

For appropriate patients, these medications can produce substantial weight loss and important metabolic benefits.

But we need to understand something:

Weight loss and fat loss are NOT necessarily the same thing.

During significant weight loss, some of the weight lost can come from lean tissue, including skeletal muscle.

The amount varies considerably depending on the individual, the therapy, nutrition, physical activity and how lean mass is measured.

But particularly for adults already experiencing age-related muscle loss, it’s something we shouldn’t ignore.

So instead of only asking:

“How much weight did I lose?”

Start asking better questions:

How much FAT did I lose?

How much MUSCLE did I preserve?

Am I stronger?

Has my body composition improved?

Am I becoming more physically capable — or simply lighter?

Those are very different conversations.

This Is Why Resistance Training and Protein Matter

Before we discuss peptides or regenerative medicine, let’s get the hierarchy right.

If you’re losing significant weight, protecting muscle starts with the fundamentals.

Resistance training.

Your body needs a reason to keep metabolically expensive muscle tissue.

Adequate protein.

You need the amino-acid building blocks required to maintain and repair tissue.

Proper nutrition.

Weight loss shouldn’t become nutrient deprivation.

Sleep and recovery.

Training provides the stimulus. Recovery helps produce the adaptation.

Monitoring body composition.

The scale only tells you what you weigh.

It doesn’t tell you what you’re made of.

Where Follistatin-344 Enters the Conversation

This brings us to an emerging area of research that I find particularly interesting: the follistatin/myostatin pathway.

Myostatin functions as one of the body’s biological regulators of muscle growth — essentially helping put a brake on excessive muscle development.

Follistatin can interfere with signaling involving myostatin and related pathways.

Because of that biology, researchers have investigated the follistatin/myostatin pathway in muscle-wasting disorders and conditions involving skeletal-muscle loss.

This is also why Follistatin-344 is sometimes discussed in regenerative and peptide circles alongside GLP-1–based weight-loss protocols.

The proposed goal is straightforward:

Reduce fat while doing everything possible to preserve valuable lean tissue.

But this distinction is extremely important:

Biological rationale does NOT equal clinical proof.

There is not currently strong clinical evidence demonstrating that commercially marketed Follistatin-344 prevents GLP-1-associated muscle loss.

So I don’t view any compound as a substitute for resistance training, adequate protein, nutrition or appropriate medical supervision.

Those remain the foundation.

Muscle and Bone: The Connection We Can’t Ignore

Why am I so concerned about preserving muscle as people age?

Because muscle doesn’t exist in isolation.

Muscle and bone are interconnected.

Muscle places mechanical stress on bone.

Muscle and bone also communicate through biological signaling.

When muscle strength and function decline, mobility and stability can decline with them.

That can increase the likelihood of falls.

At the same time, declining bone strength can increase fracture risk.

Sarcopenia describes age-related deterioration in muscle mass, strength and function.

Osteoporosis involves deterioration in bone strength and increased susceptibility to fracture.

When poor muscle health and poor bone health occur together, researchers often describe the condition as:

Osteosarcopenia.

And that combination can become devastating as we age.

Less muscle.

Less strength.

Less stability.

Greater fall risk.

More fragile bones.

Greater consequences when a fall occurs.

That’s why muscle preservation isn’t vanity.

It’s protection.

What About Other Peptides?

Other investigational compounds are also being studied in areas related to metabolism, mitochondrial biology and tissue repair.

MOTS-c

MOTS-c is a mitochondrial-derived peptide being researched for its involvement in cellular stress responses, metabolic regulation, glucose utilization and skeletal-muscle biology.

Interestingly, exercise itself appears to interact with endogenous MOTS-c biology.

Once again, the body reminds us:

Training activates some incredibly sophisticated biology all by itself.

BPC-157

BPC-157 receives tremendous attention in performance and recovery circles.

Preclinical research has explored potential effects involving tissue repair and musculoskeletal healing.

However, human evidence remains very limited.

It should therefore be discussed for what it is:

Investigational.

Not magic.

Not a replacement for rehabilitation.

And certainly not a replacement for intelligent training.

Stop Chasing Weight. Start Building Health.

At 60, I think about training differently than I did at 30.

I’m still interested in strength.

I’m still interested in performance.

But I’m increasingly interested in capacity.

Can I keep doing what I love?

Can I remain strong?

Can I move well?

Can I recover?

Can I travel?

Can I get off the floor?

Can I continue training for another 10, 20 or 30 years?

That’s healthspan.

And skeletal muscle may be one of the greatest physical investments we can make in protecting it.

So whether you’re using a GLP-1 under medical supervision, trying to lose weight naturally or simply trying to age better, remember this:

The goal isn’t to become smaller.

The goal is to become healthier.

Don’t just lose weight.

Lose the fat. Fight to keep the muscle.

Because the muscle you protect today may be what keeps you strong, mobile and independent tomorrow.

Train for the life you still intend to live.

This is My Performance Edge.

Educational content only. Peptides and other investigational compounds discussed here are not presented as approved treatments or medical advice. Always consult an appropriately licensed healthcare professional.

BWKAuthenticEdge.com