Protein and muscle with Ozempic or Mounjaro: how to look after muscle mass

Why do you lose muscle as well as fat?

When you lose weight, lean mass often decreases. This includes muscle, water and other tissues. In a sub-study involving tirzepatide (Mounjaro), both fat mass and lean mass decreased [2]. That measurement alone does not tell us how much strength someone has lost.

Eating much less and not using your muscles makes it easier for your strength to decline. Preserving it matters for getting up, walking and maintaining your independence. It also helps you stay active once your weight stabilises. If you notice marked weakness, it is a good idea to review your plan promptly with your care team.

How much protein do you need each day?

During active weight loss, a suggested range of 1.2 to 1.6 g/kg/day is proposed [1]. This is calculated using a reference weight agreed in a consultation. Automatically using your current weight may produce an excessive figure for people living with obesity [1].

If your agreed reference weight were 70 kg, the calculation would give 84 to 112 g of protein a day. This is just an example; the professional supporting you will tailor your amount. Your age, kidney function, activity and what you can realistically eat all affect the plan.

It is more useful to look at how much you eat over several days than to hit an exact figure on one particular day. Spreading protein foods across meals is often easier when your appetite is small. If you have kidney disease, your protein intake needs individual assessment.

How can you get enough protein when you have very little appetite?

Start with a small portion of a protein-rich food at the meals you tolerate best. You could choose eggs, fish, yoghurt, fresh cheese, pulses or tofu. Eating it at the start of the meal can help you avoid leaving it on your plate when you feel full quickly [1].

When your appetite is low, smaller portions and soft textures may go down more easily, such as a smooth pulse soup, scrambled egg or oven-baked fish. If you cannot manage the whole serving, save some for later. Your plan should still include fibre and variety [1].

On a day when you feel nauseous, smaller, simpler meals may help. If you eat very little for several days in a row, speak to the person who prescribes your medicine. Only that professional should change your dose to help you eat better.

“I’ve been told to eat high-protein yoghurts”: is that enough?

A high-protein yoghurt can be handy when you cannot face a full meal. Check how much protein is in each pot and whether it genuinely helps you meet your plan. Yoghurt should not routinely replace varied meals [1].

Protein alone does not turn into muscle. Your body also needs a strength-training stimulus and enough food throughout the day [1]. If you can only manage yoghurt, it is a good idea to review your low appetite and how well you tolerate the treatment.

Strength training goes hand in hand with food

Strength training gives your muscles a reason to stay strong while you lose weight. The joint recommendations on GLP-1 treatment stress combining it with enough protein [1]. Walking benefits your health, but has less effect on preserving lean mass than strength training [1].

How you get started depends on your starting point. Sitting down and standing up from a chair, pushing against a wall or using resistance bands are options to discuss with a professional. If you already train, adapt your loads and recovery to what you eat and tolerate. Do not turn weakness into a test of willpower.

The strength you preserve matters as much as the weight you lose.

What concerns do we hear in consultations?

We see people who reach the end of the day having eaten very little overall. Breakfast is reduced to coffee; lunch, to a few bites. A large dinner then feels difficult. We review the whole day and look for two times when eating does feel manageable.

We also hear the idea that a lower number on the scales means everything is going well. We ask whether you can still lift what you could before and whether you are keeping up with your usual activities. These answers help guide the conversation, although they do not replace an assessment of strength and body composition [1].

What does it mean to end up “flabby” or weak?

This fear often mixes together changes in skin, fat and muscle. In a sub-study involving tirzepatide, approximately three-quarters of the weight lost was fat and one-quarter was lean mass [2]. The split was similar in the placebo group, so this is what we can expect when losing weight, with or without medication [2].

In consultations, we follow changes in body fat, strength and activity to assess whether you are preserving muscle. Lean mass is not exactly the same as muscle, and a single measurement is not a reason to change your medicine on your own.

If weight loss comes with increasing weakness, we review how much you are eating and how you are training. Any change to your treatment should be assessed by the person who prescribes it. To plan for maintenance, you can read how to manage weight regain after Ozempic or Wegovy.

Does “Ozempic face” mean you are losing muscle?

The phrase “Ozempic face” describes reduced facial volume and skin changes during weight loss. A review links these changes to rapid fat loss [3]. It does not demonstrate a facial effect unique to semaglutide (Ozempic, Wegovy), nor does it tell you how much muscle you have lost.

Your face can change even when your strength training and diet are well planned. We cannot promise that protein will prevent this change. Your concern deserves to be heard without treating the appearance of your face as a measure of muscle health.

How can we track progress without relying only on the scales?

We track strength and function with specific questions. Can you get up from a chair as you did before? Are you keeping up with your walks and exercises? If body composition is measured, we interpret it with its limitations and alongside these observations [1].

One week of eating less does not define your overall progress. It is important to spot a trend towards losing strength or persistent difficulty eating. That helps us adjust meals and exercise, and seek medical advice when needed.

To plan your meals, see what to eat with GLP-1 treatment and a weekly meal plan. To understand the treatment as a whole, read the GLP-1 medicines guide. For specific information, see the Mounjaro and Ozempic guides.