The 30-second summary
- There is no official Mounjaro diet. The NHS says to eat a healthy, balanced diet while you take it. The useful question is how to eat well on a much smaller appetite.
- Protein first, every meal. Your appetite runs out sooner, so put protein on the plate before anything else. Your daily target depends on your weight and dose, and the calculator works yours out.
- Take extra care after each dose increase. Nausea, diarrhoea, vomiting, constipation and stomach pain are very common side effects, and smaller, plainer meals are easier to manage while your body adjusts.
What Mounjaro does to eating
Mounjaro is tirzepatide. Its UK prescribing information describes it as a long-acting GIP and GLP-1 receptor agonist, which means it acts on two gut hormone receptors rather than one, and it notes that it delays gastric emptying: food leaves your stomach more slowly. The NHS puts the effect plainly. Tirzepatide works for weight loss by reducing your appetite and helping you feel fuller for longer.
In the SURMOUNT-1 trial, adults with obesity lost an average of 15.0% of their body weight over 72 weeks on the 5 mg dose, 19.5% on 10 mg and 20.9% on 15 mg, compared with 3.1% on placebo. Losing weight at that pace means losing some muscle alongside fat, which is why what you eat still matters. (See why muscle is the number that matters.)
In the United States the same medicine is sold as Zepbound. The FDA approved it in November 2023 for chronic weight management, for use alongside a reduced-calorie diet and more physical activity. Everything on this page applies to both names.
The plate, in order
- Protein first. Chicken, fish, eggs, Greek yoghurt, cottage cheese, tofu, beans or lentils. When appetite gives out after a few bites, you want those bites to have been protein. (See protein on a GLP-1.)
- Vegetables and fibre next. Fibre, taken with enough fluid, is the usual first step for constipation, which is one of Mounjaro's very common side effects. (See constipation on a GLP-1.)
- A little starch or fat to finish. A few potatoes, some rice, a spoon of olive oil. Part of the meal, not the centre of it.
The weeks that need the most care
Mounjaro starts at 2.5 mg once a week. After 4 weeks the dose goes up to 5 mg, and any further increases come in 2.5 mg steps, each at least 4 weeks after the last, to a maximum of 15 mg a week.
Each increase is a change your digestion has to adjust to. In the days after one, a few habits make eating easier:
- Eat smaller amounts, more often, if a normal plate sits heavily.
- Choose plainer food over rich, greasy or fried meals while your stomach settles.
- Keep drinking through the day. Diarrhoea and vomiting both cost fluid.
If side effects are severe or do not settle, tell your prescriber rather than pushing on.
Two things that are specific to Mounjaro
Alcohol. The NHS says it is best to avoid alcohol while using tirzepatide, because it can increase side effects such as feeling or being sick. (See GLP-1 medicines and alcohol.)
The contraceptive pill. Mounjaro's prescribing information says reduced effectiveness of oral contraceptives cannot be excluded. It advises switching to a non-oral method, or adding a barrier method such as condoms, for 4 weeks after starting and for 4 weeks after each dose increase. The NHS gives the same advice. (See GLP-1 medicines and birth control.)
A day of eating on Mounjaro
This is an illustration, not a prescription. Each dish is a full recipe with its portion stated and its nutrition calculated from the ingredients:
- Breakfast: Baked eggs with spinach, cottage cheese and feta
- Lunch: Chicken and white bean open sandwich
- Dinner: Dijon-dill salmon with crushed potatoes
On a low-appetite day, a smaller portion of each is fine, and every recipe page lets you switch to one. For more, browse the high-protein GLP-1 recipes or the high-fibre GLP-1 recipes.
What to do with this
General advice is a starting point, not your number. The calculator works out your calorie target, your protein floor and how much you are likely to manage at your dose. The worked examples show what that looks like for Mounjaro 7.5 mg at 100 kg and Mounjaro 15 mg at 92 kg.
Sources
- Mounjaro KwikPen solution for injection in pre-filled pen: Summary of Product Characteristics. electronic medicines compendium. emc
- NHS. Tirzepatide. nhs.uk
- Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med 2022. PubMed
- US Food and Drug Administration. FDA Approves New Medication for Chronic Weight Management. 8 November 2023. fda.gov
Medical disclaimer: Articles in the foodose research library are educational, not medical advice. Talk to your prescriber or a dietitian about your own nutrition. See our full medical disclaimer.