You’ve lost your appetite; you’re eating half as much as you used to, and the scale still isn’t moving.
Feeling stuck on Mounjaro can be really frustrating, especially when you follow the plan perfectly.
The reason is often the opposite of what you might think. Eating too little can cause your body to break down muscle protein. When you lose muscle, your metabolism slows down.
How Mounjaro Works on Your Appetite
Mounjaro (tirzepatide) mimics two hormones produced in your gut: GLP-1 and GIP.
These hormones tell your brain that you're full, so you naturally eat less. They also help control your blood sugar and improve how your body uses insulin.
The medication reduces your hunger, but it doesn't control what you choose to eat.
What the First Few Weeks Look Like
A lot of people see weight loss between weeks four and six. You might notice more weight loss after about 12 weeks.
Pay attention to the signs that aren’t just numbers. Your jeans might feel looser, your cravings might decrease, and you might find yourself snacking less.
Losing weight gradually is safer because dropping pounds too quickly can increase your risk of gallstones and hair loss.
Why Eating Too Little Causes a Mounjaro Plateau
The plateau develops in three steps. First, your calorie intake drops, then your protein intake drops too, and finally, your body starts breaking down muscle to compensate for the calorie deficit.
Your Calorie Intake Drops Further Than You Realise
Appetite suppression works, sometimes a bit too well.
Some people on Mounjaro eat about 800 calories a day without realising it. At that level, their daily protein usually doesn’t go over 60 g.
Say you’re 1.70 m tall and weigh 90 kg, which puts your body mass index (BMI) at about 31. If you want to get down to 75 kg, you should aim for at least 90 g of protein each day. So, getting only 60 g means you're 30 g short.
What Happens When Your Protein Drops Too Low
Your body needs amino acids every day, and it gets them from the protein in your food. If you don’t get enough protein, your body starts taking it from your muscles.
Muscle burns energy all the time, even when you’re sleeping. If you lose some muscle, you’ll burn fewer calories when you’re at rest.
Why Eating Less Makes It Harder
When progress slows down, the natural reaction is to reduce your portion sizes again. This lowers your protein intake even more, and your body starts to break down more muscle.
Why Is Mounjaro Not Working for Me?
In most cases, it’s working. Your appetite has dropped, so the medication is doing its job.
A stall usually means something else is going on. Low protein is a common reason, and your dose, sleep, and hidden calories can all play a part.
Watch for these signs:
- You feel dizzy or light-headed when you stand up
- You’re tired by early afternoon
- Your hair sheds more around the second or third month
- You feel cold, foggy, or irritable
- Your digestion has slowed down
Dizziness on Mounjaro often comes from not drinking and not eating enough. Nausea can make you less likely to drink, and the medication can dull your thirst.
If it keeps happening, talk to your doctor or pharmacist before changing your dose.
How Much Protein Do You Need on Mounjaro?
Most guidance for people losing weight falls between 1.2 and 2.0 g of protein per kilogram of body weight each day. Around 1.6 g per kilogram is a sensible middle ground.
Work Out Your Number
Which weight should you use? To work out your BMI, divide your weight in kilograms by your height in metres squared. If your BMI is under 30, stick with your current weight.
If your BMI is 30 or above, use your goal weight instead, since using your current weight may overestimate your protein needs.
In the earlier example, a BMI of about 31 means you’d use the 75 kg goal weight. At 1.6 g per kilogram, that gives you 120 g of protein a day.
Split It Into Four
One big dinner won't cut it. Your body needs protein throughout the day. Spread the 120 g over four meals: breakfast, lunch, an afternoon snack, and dinner, aiming for 25 to 40 g per meal.
Fibre and Fluid Alongside Protein
Try to get about 30 grams of fibre each day to help with digestion. Drink most of your water between meals. It's easier to drink when your stomach isn't full.
How Resistance Training Helps You Keep Muscle
Protein provides your body with what it needs, while resistance training helps your body retain muscle.
Try to get 150 minutes of activity each week, including two strength workouts. Bodyweight exercises, resistance bands, and dumbbells all count.
Doing ten minutes of squats and push-ups in your kitchen counts as a workout.
Every few weeks, add a little weight or do a few more reps. This signals your body to maintain its muscle.
Training twice a week can raise the example target from 120 g to 150 g a day.
You’ll have days when you feel low on energy, and that’s completely normal. On those days, shorten your workout, reduce a few sets, but keep the movements.
What Else Could Be Slowing Your Weight Loss?
Once your protein is on track, there are four other things to check. Any of them could slow down your progress.
Time Since Your Last Dose Increase
How long have you been on your current dose of Mounjaro? If your progress has slowed, ask your prescriber whether your current dose still suits you.
If you’ve missed any injections, tell your prescriber before you take your next dose.
Calories You Don’t Notice
Milky coffees, weekend wine, cooking oils, and a bit of cheese can really add up. It doesn’t feel like a meal, so your calorie deficit disappears without you realising it.
A three-day food diary often reveals this pattern.
Sleep, Alcohol and Cortisol
Not getting enough sleep makes you hungrier the next day and makes it tougher to resist cravings. High cortisol levels after a stressful few months can also hinder your fat loss.
When to Speak to Your Doctor
Some causes have nothing to do with your habits. Thyroid problems, insulin resistance, other medications and vitamin deficiencies can each affect your weight-loss results.
A blood test from your doctor or an online doctor service can help rule some of them out.
How to Hit Your Protein Target Every Day
You don’t need a spreadsheet or a new routine for this.
Just have a protein smoothie for breakfast, lunch, and an afternoon snack, then enjoy a balanced meal in the evening.
This way, you can hit 120 grams of protein without adding more food to your plate.
Liquid protein is great when you don’t feel like eating. It may be digested more quickly than some solid protein foods.
On days when you feel nauseous, a smoothie is easier to handle than anything else. It’s much easier to finish a smoothie than a plate of chicken.
Get Your Weight Loss Back on Track With EXALT
We created our 7-Day GLP-1 Nutrition Support Plan with a registered dietitian. It provides up to 170 g of protein and 30 g of fibre each day.
Our fresh smoothies contain 20 to 40 g of protein per bottle. You can also add whey, vegan protein, or collagen powders to boost your daily intake.
Many customers schedule their delivery for injection day, when their appetite tends to drop. You can pause or cancel your order at any time.
If you're not losing weight on Mounjaro, it’s important to focus on getting enough protein first. Track your daily intake and focus on your protein needs. If your weight loss stops, talk to your healthcare provider.
Start with the 7-Day GLP-1 Nutrition Support Plan today!
