Why Your GLP-1 Weight Loss May Have Stalled or Is Slower Than Anticipated — (Hint: It’s Not From Eating Too Much)

By Rachel Kalenkiewicz, DNP, CRNA, ARNP
Kalen & Co. Aesthetics – Cedar Rapids, Iowa

Category: GLP-1 Weight Loss Support | Metabolism

If you're using GLP-1 medications like semaglutide or tirzepatide and notice your weight loss has stalled or is moving at a snail’s pace — even though you're taking your injections consistently, drinking multiple Stanley cups of water, incorporating weight resistance, and prioritizing protein — it might not be because you're eating too much.

In fact, you could be eating too little.

Let’s talk metabolism.

When you cut calories too low — especially for weeks on end — your body goes into conservation mode. It slows your metabolism to preserve energy, prioritizing essential functions (like keeping your heart and brain going) over fat burning. This survival mechanism is powerful and can completely stall weight loss, even with GLP-1s on board.

Essentially, it can derail your basal metabolic rate (BMR). While eating near your BMR might work for short periods, doing so for too long teaches your body to adapt to less. You burn fewer calories at rest, hold onto fat more efficiently, and risk reversing your progress — all while feeling increasingly fatigued.

👉 Hormonally, this can be especially disruptive for women.
Low calorie intake over time can signal to your body that it’s not a safe environment for reproduction — which impacts thyroid function, cortisol levels, and sex hormones like estrogen and progesterone. You may notice irregular cycles, worsened PMS, hair thinning, or mood shifts — all signs your metabolism and hormones are under stress.

This is one reason why chronic undereating, paired with appetite suppression from GLP-1s, can become a long-term barrier to success.

In fact, this pattern is common in newer GLP-1 users.

These medications suppress appetite, which is helpful — but sometimes too helpful. I often see clients unintentionally eating far below their metabolic needs, assuming that less food = faster results. But it often has the opposite effect.

If you’re only eating one meal a day, skipping breakfast, or trying to “stretch your fast” — your metabolism might be slowing down in response.

So yes — intermittent fasting or skipping meals might actually be slowing your progress on GLP-1s.

While fasting works for some, most GLP-1 clients do better with small, consistent meals throughout the day that stabilize blood sugar and signal to the body:
🧠 “It’s safe to burn fat. We’re not in a famine.”

What to do instead:

✅ Eat enough to meet your true metabolic needs — not just the bare minimum. Chronic undereating slows your burn. If you’re unsure what that range is, start with a ballpark TDEE (Total Daily Energy Expenditure) and adjust from there.

✅ Prioritize protein at every meal — and keep protein-rich snacks handy (string cheese, boiled eggs, nut butters, cottage cheese, Greek yogurt, etc.). Protein preserves lean muscle and keeps you fuller longer.

✅ Don’t skip meals. Even if your appetite is low from GLP-1s, your metabolism still needs consistent fuel to function well.

✅ Move your body daily — but don’t overdo it.
Walking, strength training, or short resistance band sessions are enough. Overtraining while undereating = hormonal chaos, especially for women.

✅ Don’t fear carbs.
Whole-food carbs like berries, beans, potatoes, and oats support your thyroid, insulin sensitivity, and hormone balance. Low-carb isn't always better.

✅ Watch for signs your metabolism is under stress:
Fatigue, brittle nails, feeling cold, irregular cycles, or poor sleep are red flags. These are not "just part of weight loss" — they’re signs your body wants more support.

✅ Hydrate + mineral balance.
Keep water intake high but also consider replenishing electrolytes, especially if you're low-carb or experiencing fatigue or cramping.

Bonus tip: Track your intake for a few days

Not to obsess over numbers, but just to get a clearer picture. Many GLP-1 clients are surprised to find they’re eating <800–1000 calories/day without realizing it — and once they bump it up slightly, the scale moves again.

Extra Support for When GLP-1s Need a Nudge

✅ Support your metabolism with key nutrients.
Consider supplementing with vitamin B12 or NAD+ injections — especially if you’re feeling fatigued, mentally foggy, or under-recovered. These can help boost cellular energy, support fat metabolism, and reduce common side effects of GLP-1 therapy like sluggishness or loss of motivation.
👉 Available at Kalen & Co. under “Wellness & Vitamin Injections” as a quick, add-on service during your visit.

Bottom Line:

Eating too little can cause your body to slam the brakes on weight loss.
Instead of restricting more, the key is to fuel smartly — enough to preserve metabolism and support sustainable fat loss.

If you’re unsure how much you should be eating or whether your intake is working against your goals, I’m here to help.

👉 Book a GLP-1 check-in or virtual consult
We’ll troubleshoot and optimize your plan together.