GLP-1s and Fitness — What Your Coach Actually Wants You to Know

By CJ Critney • August 3, 2026 • 9 min read

GLP-1 medications — Ozempic, Wegovy, Mounjaro, Zepbound — have become the most talked-about weight loss tool in a generation. Most of the conversation is either "they're miracle drugs" or "they'll ruin your body." Both are wrong. Here's the honest coach take on what actually happens when you combine GLP-1s with real training — and how to do it right.

What GLP-1s Actually Do

GLP-1s work by mimicking a natural hormone that:

  1. Slows gastric emptying (food stays in your stomach longer = you feel full longer)
  2. Reduces appetite signals in your brain
  3. Improves insulin sensitivity

The result: you eat significantly less, often 30-50% less. Fat loss happens fast — most people drop 15-20% of body weight over 6-12 months.

That's the good news. Now the trade-offs.

The Real Risks Nobody Talks About Enough

1. Muscle loss is real and significant

When you're in a rapid caloric deficit, your body loses BOTH fat AND muscle. Some studies show up to 40% of weight lost on GLP-1s can be lean tissue (muscle) if you don't actively protect it. That's a disaster long-term.

Why: less muscle = lower metabolism = weight regain when you stop the medication + increased frailty as you age.

2. Bone density can drop

Rapid weight loss + reduced protein intake = accelerated bone density loss. Especially concerning for women over 40 and men over 50.

3. Nutritional deficiencies

Eating 30-50% less food = eating 30-50% fewer micronutrients (vitamins, minerals). Iron, B12, calcium, magnesium — all commonly deficient in GLP-1 users.

4. Loss of muscle = loss of function

The weight comes off. But if your legs are weaker, your arms can't carry groceries, your back hurts when you pick up your kid — you have "success" that feels like failure.

The reality: GLP-1s handle appetite. They don't handle protein, muscle, strength, hormones, sleep, or stress. Those still land on YOU (and your coach). Take the medication without addressing the rest and you'll end up thinner but weaker, more tired, and more fragile.

What Actually Needs to Change on GLP-1

1. Protein target goes UP, not down

Because appetite drops, most GLP-1 users end up eating 50-80g of protein per day. That's catastrophic for muscle preservation. Target: 0.8-1g protein per pound of goal body weight. Non-negotiable.

Practical strategies: prioritize protein FIRST at every meal. Protein shakes to fill gaps. Greek yogurt, cottage cheese, jerky as snacks. Overnight casein shake.

2. Strength training becomes MORE important, not less

You cannot skip strength training on GLP-1s. Full stop. Without heavy resistance training, you WILL lose significant muscle. With it, you preserve most of it and lose primarily fat.

Target: 3 full-body strength sessions per week minimum. Compound lifts. Progressive load. This is medical-grade necessary.

3. Electrolytes daily

GLP-1s reduce total food intake, which means reduced sodium, potassium, and magnesium. Result: fatigue, brain fog, headaches, cramping. Take a daily electrolyte packet (LMNT, Element, or unflavored).

4. Fiber priority

GLP-1s slow gastric emptying. Constipation is common. 30-40g of fiber per day: vegetables, fruit, oats, legumes.

5. Water — a LOT of it

128oz/day minimum. Reduced food intake reduces water intake. Dehydration on GLP-1 is common and makes side effects (nausea, fatigue) much worse.

6. Bone-strengthening work

Weight-bearing exercise (walking, lifting) + adequate calcium and vitamin D. Especially critical for women.

7. Regular bloodwork

Check nutritional status quarterly while on the medication. Iron, B12, vitamin D, calcium, thyroid function.

The Coach's Perspective

Here's my honest take from working with clients who are on GLP-1s and clients who aren't:

Should You Consider One?

That's a medical decision between you and your doctor. Factors that suggest GLP-1 might make sense:

Factors that suggest maybe not:

On a GLP-1 and want a coach who understands the nutrition/training side?

Book a free 15-min call. We'll talk through what you need on top of the medication to actually protect your muscle and get real results.

Book Your Free 15-Min Call →

The Bottom Line

GLP-1s are a legitimate tool that reduces appetite significantly. They're also a fast track to muscle loss, bone density loss, and nutritional deficiency if used without a plan.

Take them under medical supervision. Prioritize protein aggressively. Strength train seriously. Manage electrolytes and fiber. Do bloodwork. And use the medication as a partner in a bigger transformation — not a shortcut around it.

The people who look and feel BEST on GLP-1s are the ones who treat the medication as one tool among many. Not the answer.