Mounjaro and protein intake

When you start your Mounjaro weight loss journey, it’s natural to focus on the numbers you see on the bathroom scales. But real, long-term success with weight loss is about much more than just losing weight—it’s about keeping your body strong, healthy, and energised. One of the most important things you can do for your health, especially when using medications like Mounjaro, is to maintain your protein intake and preserve your muscle. In this blog, we explain why you should maintain your protein intake when taking Mounjaro and learn about the role of muscle in weight loss.

Key takeaways

• Maintaining muscle is crucial for successful weight loss with Mounjaro:
  Losing weight isn’t just about dropping numbers on the scale—keeping your muscle helps you stay strong, energised, and supports a healthy metabolism.
• Protein intake protects your muscles while losing weight:
  Eating enough protein ensures your body has the building blocks needed to preserve muscle, which prevents your metabolism from slowing down during weight loss.
• Mounjaro works best when combined with protein and strength training:
  Combining a protein-rich diet with regular resistance exercises helps you keep muscle, burn more fat, and achieve better long-term results.
• Choose a variety of healthy protein sources:
  Include foods like eggs, lean meats, fish, beans, nuts, and dairy in your meals. These options help you meet your daily protein needs without relying on supplements.
• Focusing on protein and muscle health supports lasting weight management:
  Prioritising protein intake and muscle maintenance while using Mounjaro not only boosts weight loss results but also improves your health, keeps you feeling strong, and reduces the risk of regaining weight in the future.

Mounjaro, the weight loss sensation

You probably have heard about the miraculous weight loss sensation, Mounjaro. In this section, we will quickly go over what it is and how it works before diving into why you should increase your protein intake when taking Mounjaro.

What is Mounjaro?

Mounjaro is a ground-breaking weight loss injection developed by Eli Lilly, with the active ingredient tirzepatide.

What makes Mounjaro different from other weight loss medications is that it acts like two natural hormones in your body—GLP-1 (Glucagon-Like Peptide-1) and GIP (Glucose-Dependent Insulinotropic Polypeptide) [1].

These hormones, known as incretins, help regulate blood sugar levels and play a crucial role in managing weight.

How does Mounjaro work?

Because Mounjaro targets both GLP-1 and GIP at the same time, it’s sometimes called a “twincretin.”

This unique action helps you lose weight in three main ways:

• It reduces your appetite, so you feel less hungry [2].
• It helps you feel full for longer after eating [2].
• It slows down how quickly your stomach empties, which helps you eat less overall [2].

Early research showed that combining these two hormones was much more effective for weight loss than using just one [3].

The benefits of GLP-1 and GIP are listed in the table below:

Muscle: More than meets the eye

Muscle isn’t just for athletes or bodybuilders. Every person needs muscles to move, stay active, and keep their body working well. What many people don’t realise is that muscle is also a key player in your metabolism—the process your body uses to turn food into energy [4].

Muscles burn more calories than fat.

Yes, you read that right, muscle tissue burns more calories than fat, even when you’re just sitting or sleeping. This means that the more muscle you have, the more calories your body uses throughout the day.

The good news is that the more muscle you carry, the more fat you burn. So, now it’s time to renew that gym membership and start pumping iron!

A study found that just ten weeks of strength training boosted people’s resting metabolism by 7% and helped them lose 1.8kg of fat, even without significant changes to their diet [5].

So, if you want your Mounjaro weight loss plan to work as efficiently as possible, keeping your muscles and even growing them should be part of your weight loss plan.

Why muscle loss can happen during weight loss

When you lose weight—especially if you’re cutting calories or using weight loss medications like Mounjaro—it’s not just fat that disappears.

If you aren’t careful, you can lose muscle too. This is a problem because losing muscle can slow your metabolism, make it harder to maintain weight loss, and leave you feeling tired or weak [6].

Experts always recommend combining weight loss with activities that strengthen your muscles, such as resistance exercises (think lifting weights, using resistance bands, or bodyweight moves like squats and push-ups).

More weight loss occurs when resistance training is combined with a high-protein diet

A study examined overweight or obese adults with type 2 diabetes and compared the effects of two low-fat, calorie-restricted diets—one with a higher protein content and one with a higher carbohydrate content—both with and without resistance exercise (such as weight training).

Over 16 weeks, all groups lost weight and demonstrated improvements in their blood sugar and heart health. However, the group that combined a higher-protein diet with resistance exercise lost the most weight and body fat, and saw the most significant reduction in waist size [7].

In short, adding resistance training and increasing protein intake while reducing calorie intake helped people with type 2 diabetes lose more weight and fat, even though everyone experienced similar improvements in blood sugar and cholesterol levels [7].

Protein: The building block for muscle

When you start Mounjaro, your appetite will gradually decrease as you work through the dosing schedule, but there’s one food group you should not neglect… protein!

We have learnt that having more muscle is the secret to burning more calories at rest, so what’s the secret to keeping your muscle while you’re losing weight? Protein! Protein is an essential nutrient your body needs to build and repair muscle.

If you don’t get enough protein, your body may break down muscle to use for energy, especially if you’re eating fewer calories.

How much protein do you need?

Getting enough protein is essential for maintaining strong muscles. Most health experts recommend that adults eat about 0.8 to 0.9 grams of protein for every kilogram of body weight each day. For example, if you weigh 70 kg, that means you should aim for around 56 to 63 grams of protein daily. This amount is designed to maintain your body’s balance and support muscle health for most individuals.

These guidelines are similar in the UK, USA, Canada, and worldwide. However, some research suggests that eating a bit more protein—between 1.2 and 1.6 grams per kilogram of body weight—can help you build or maintain muscle even better, whether you’re young or older [8].

Most experts recommend at least 0.8 grams of protein per kilogram of body weight each day, though some people may benefit from even more, especially if they’re very active or trying to build muscle.

Including protein at every meal can help you stay full, maintain steady energy levels, and protect your muscles.

Best sources of protein for weight loss

Getting enough protein doesn’t have to be complicated or expensive. Here are some easy and healthy protein sources you can include in your daily meals:

• Eggs
• Lean meats and poultry (like chicken or turkey)
• Fish and seafood
• Greek yoghurt
• Cottage cheese
• Beans, lentils, and chickpeas
• Nuts and seeds

If you struggle to get enough protein from food alone, protein supplements such as whey or plant-based powders can be a convenient option. However, most people can meet their protein needs through a balanced diet without the need for supplements.

How protein helps with Mounjaro weight loss

Taking Mounjaro can help you lose weight by controlling your appetite and helping your body use insulin more effectively. But if you don’t get enough protein, you risk losing muscle along with fat. This is important because:

• Protein helps you feel full: High-protein foods keep you satisfied for longer, which can help you eat less and stick to your weight loss plan. This is especially useful when Mounjaro is already helping to curb your appetite.
• Protein protects your muscles: When you’re losing weight, your body can break down muscle for energy if it doesn’t have enough protein. Maintaining a high protein intake helps protect your muscles.
• Protein supports your metabolism: More muscle means a higher metabolism, so you burn more calories, even at rest.

Diet and exercise: The perfect team

Combining a healthy, protein-rich diet with regular strength training is the most effective way to maintain muscle strength during weight loss.

A study found that women who combined diet changes with exercise lost more fat and retained more muscle than those who only changed their diet [9].

This approach not only helps you lose weight but also improves your overall health and reduces your risk of regaining weight in the future.

Practical tips for maintaining muscle and protein intake

• Aim for a source of protein at every meal—for example, eggs at breakfast, chicken or beans at lunch, and fish or tofu at dinner.
• Include a variety of protein sources to get all the essential amino acids your body needs.
• Don’t forget about snacks—Greek yoghurt, a handful of nuts, or a protein smoothie can help you reach your daily protein goals.
• Stay active—strength training two to three times a week can make a big difference.
• Track your progress—if you’re losing weight quickly, check in with your healthcare provider to ensure you’re not losing muscle.

Why protein matters for your long-term health

Maintaining your muscle and protein intake while taking Mounjaro for weight loss isn’t just about looking good—it’s about feeling good, staying strong, and keeping the weight off for good. Muscle helps you move better, keeps your metabolism high, and protects your health as you age.

How to get Mounjaro from Courier Pharmacy

1. Fill out our online questionnaire
   Start by completing our secure online medical questionnaire. This helps our pharmacists and prescribers check if Mounjaro is right for you and ensures your safety.
2. Upload a recent photo
   You’ll be asked to upload a clear, up-to-date photo of yourself. This is for identity verification and safe prescribing.
3. Show proof of dose titration (for higher doses)
   If you’re requesting a higher dose of Mounjaro, you’ll need to provide evidence, such as prescription records, photos of previous pens, or other documentation, to confirm you have safely increased your dose.
4. Enter your GP details
   Share your GP’s contact information so we can keep your doctor updated about your Mounjaro treatment and support your ongoing care.
5. Complete a follow-up video consultation
   To meet the latest regulations, you’ll have a video call with our clinical team. This ensures you’re using Mounjaro safely and gives you a chance to ask any questions.

Why buy Mounjaro from Courier Pharmacy?

• Competitive prices: Get Mounjaro at some of the best prices online, making your treatment more affordable.
• Free sharps bin: We include a free sharps bin for safe disposal of used injection pens.
• Free needles: All the needles you need for your treatment are included at no extra cost.
• Free alcohol wipes: Every order comes with free alcohol wipes to keep your injections safe and hygienic.
• Free consultations: Enjoy free medical consultations with our experienced team, from your first assessment to ongoing support.
• Support for side effects: If you experience any severe side effects, we can provide additional medicines to help you manage them and stay comfortable.

At Courier Pharmacy, we’re dedicated to making your experience safe, affordable, and supportive. If you have any questions or need help, our friendly team is always here for you.

This information is for general guidance only. For personalised medical advice, please consult your doctor or healthcare provider.

References

1. Courier Pharmacy. (n.d.) Mounjaro side effects. Available at: https://courierpharmacy.co.uk/mounjaro-side-effects-2/ (Accessed: 18 June 2025).
2. Courier Pharmacy. (n.d.) Can you drink alcohol while taking Mounjaro? Available at: https://courierpharmacy.co.uk/can-you-drink-alcohol-while-taking-mounjaro-2/#h-how-does-mounjaro-cause-weight-loss (Accessed: 18 June 2025).
3. Finan, B., Ma, T., Ottaway, N., Müller, T.D., Habegger, K.M., Heppner, K.M., Kirchner, H., Holland, J., Hembree, J., Raver, C. and Lockie, S.H., 2013. Unimolecular dual incretins maximize metabolic benefits in rodents, monkeys, and humans. Science translational medicine, 5(209), pp.209ra151-209ra151.

4. Argilés, J.M., Campos, N., Lopez-Pedrosa, J.M., Rueda, R. and Rodriguez-Mañas, L., 2016. Skeletal muscle regulates metabolism via interorgan crosstalk: roles in health and disease. Journal of the American Medical Directors Association, 17(9), pp.789-796.
5. Westcott, W. L. (2012). Resistance training is medicine: Effects of strength training on health. Current Sports Medicine Reports, 11(4), 209-216. https://doi.org/10.1249/JSR.0b013e31825dabb8
6. McCarthy, D. and Berg, A., 2021. Weight loss strategies and the risk of skeletal muscle mass loss. Nutrients, 13(7), p.2473.
7. Wycherley, T.P., Noakes, M., Clifton, P.M., Cleanthous, X., Keogh, J.B. and Brinkworth, G.D., 2010. A high-protein diet with resistance exercise training improves weight loss and body composition in overweight and obese patients with type 2 diabetes. Diabetes care, 33(5), pp.969-976.
8. Nunes, E.A., Colenso?Semple, L., McKellar, S.R., Yau, T., Ali, M.U., Fitzpatrick?Lewis, D., Sherifali, D., Gaudichon, C., Tomé, D., Atherton, P.J. and Robles, M.C., 2022. Systematic review and meta?analysis of protein intake to support muscle mass and function in healthy adults. Journal of cachexia, sarcopenia and muscle, 13(2), pp.795-810.
9. Joseph, G., et al. (2020). A comparison of diet versus diet + exercise programs for health improvement in middle-aged overweight women. Women’s Health (Lond), 16, 1745506520932372. https://doi.org/10.1177/1745506520932372