GLP-1 Diet App: What to Track and What to Eat (October 2026)

01 · The core answer

What should a GLP-1 diet app actually do?

A useful GLP-1 diet app does a small number of jobs well: it reminds you of your weekly dose, records your injection site, tracks protein and fluids, and lets you note side effects and weight over time. Anything beyond that is a bonus.

Mounjaro is a once-weekly injection, so the schedule matters more than daily calorie precision. A reminder that stops you losing track of which day you inject is worth more than a huge food database.

Our own GLPTrackr is a free companion app for tracking a GLP-1 journey, available on iOS and Android.

Be sceptical of any app that promises results or generates a plan without knowing your medical history. Anything clinical, such as dose changes or persistent vomiting, belongs with your prescriber, not an app.

02 · Your next step

Do I need a GLP-1 diet plan or book?

Most people do not need a bought plan, book or recipe collection. Mounjaro is licensed alongside a reduced-calorie diet and increased physical activity, and the practical guidance is simple enough to fit on a page.

If you like structure, a recipe book can help with ideas for small, protein-led meals. Choose one written by a registered dietitian or clinician, and avoid any that make dramatic weight-loss claims or sell a 'GLP-1 boosting' formula. Our guides to what a GLP-1 diet consists of and a balanced diet on treatment are free.

If you are not yet on treatment and want to know whether it suits you, our weight loss clinic explains the pathway. A free online consultation is reviewed by a GPhC-registered prescriber.

03 · What to eat on treatment

What to eat while on a GLP-1 medicine

The recommended diet on Mounjaro is an ordinary, sustainable reduced-calorie diet, not a special regime. No food is banned on Mounjaro — including bananas — but some choices make treatment easier and more effective.

Prioritise protein at each meal, vegetables and fibre, and regular fluids. Tirzepatide activates GIP and GLP-1 receptors, which helps regulate appetite and slows how quickly the stomach empties, so most people feel fuller sooner and less hungry between meals.¹

That slower emptying is why portion size matters. Large portions sit heavily, and many people feel worse after very fatty, fried or very sugary food. Smaller, slower meals work better. The aim is a sustainable deficit, not a perfect food list.¹

For beginners, a simple template works: a protein source on the plate first, vegetables or salad alongside, a modest portion of wholegrain carbohydrate, and water within reach.

04 · What not to eat

What not to eat on GLP-1 treatment

Nothing is forbidden, but several things commonly make side effects worse. Very fatty, fried and very sugary foods are the usual culprits for feeling unwell, and large portions are another.¹

Two further points are worth knowing. Alcohol has no direct interaction with Mounjaro, but drinking on a reduced appetite and emptier stomach can hit harder than usual, and alcohol adds calories that work against your goals. If you also take insulin or a sulfonylurea, alcohol increases the risk of low blood sugar.¹

Coffee and tea are fine. There is no interaction between Mounjaro and caffeine, though strong coffee on an empty, slower-emptying stomach can aggravate nausea or reflux for some people, and high-calorie coffee drinks are an easy place for the calorie deficit to leak. 'Coffee rules' circulating on social media have no clinical basis.¹

05 · Protein, muscle and exercise

Protein, muscle and exercise

Protein is the nutrient most worth tracking, because lower appetite makes it easy to undereat. Some of any rapid weight loss comes from lean tissue, and protecting muscle protects your metabolism, strength and appearance.¹

The two levers are adequate protein — aim to include a protein source at every meal, which is harder when appetite is low — and resistance exercise two or more times a week. This matters more, not less, as the dose rises and appetite falls.¹

Increased physical activity is part of the licence, not an optional extra. Nothing special is required: regular moderate activity such as brisk walking, plus resistance work for muscle. Start where you are and build. On injection days with early side effects, lighter movement still counts. Exercise also protects against regain if you later stop treatment.¹

This is where an app earns its place. A simple protein tally and a weekly activity note are more useful than detailed macro charts.

06 · Hydration and supplements

Hydration, shakes and supplements

Drinking enough matters more on Mounjaro than usual. Reduced appetite means less fluid from food, and vomiting or diarrhoea can dehydrate you quickly, which is the main route to the rare kidney problems reported with this class. Keep water within reach and treat inability to keep fluids down as a contact-your-clinical-team issue, not something to push through.¹³

No supplement is required with Mounjaro, but eating much less can leave gaps, so a standard daily multivitamin is a reasonable safety net while losing weight. Discuss anything beyond that with a pharmacist.¹

Products sold as 'natural GLP-1 boosters' are not equivalents and are not substitutes for prescribed treatment. These are usually low-cost supplements with no clinical oversight. The same caution applies to 'GLP-1 shakes' marketed as boosting your own hormones. A protein shake can be a convenient way to hit a protein target when appetite is low, but it does not act on your GLP-1 receptors.¹

Oral supplements, like other oral products, may be absorbed more slowly when you start treatment.¹

07 · Anti-diet and realistic expectations

Anti-diet thinking and realistic expectations

An 'anti-diet' approach and a medicated approach can sit together if you treat food as nourishment, not punishment. Mounjaro is licensed alongside a reduced-calorie diet and increased physical activity, so the aim is a pattern you can keep, not rules you obey perfectly.

On results, the trial evidence is clear but averaged. In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone. These are trial averages — individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.²

That is why an app showing your own weight trend over weeks is more honest than comparing yourself with an average. Our guides on whether a GLP-1 diet works and GLP-1 diet reviews cover this further.

08 · Cost and getting started

If you are not yet on treatment

Apps and books do not replace the medicine, and they do not replace a prescriber's assessment. Mounjaro (tirzepatide) is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. NHS access exists but is being phased in over several years, which is why many people who meet the licensed criteria choose regulated private treatment.

The consultation is free, delivery is free next-day and tracked, and ongoing monthly reviews are included.

Our explainer on what a GLP-1 diet means is a good next read if you are still deciding.

09 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹