How to Eat in a Calorie Deficit When You're on Mounjaro or Wegovy

A calorie deficit simply means your body is burning more energy than you're taking in. Most people find that their appetite naturally decreases on GLP-1 medicines like Wegovy (semaglutide) or Mounjaro (tirzepatide), which can make eating less feel less of a struggle — but a smaller plate still needs to carry the right nutrients, or energy levels and muscle mass can suffer.

Prioritise protein at every meal

When calorie intake is lower, protein becomes especially important. It helps preserve lean muscle, keeps you feeling fuller for longer, and takes more energy to digest than carbohydrates or fat. Many people on GLP-1 medicines find small, protein-first meals sit most comfortably — think eggs, fish, chicken, Greek yoghurt, legumes, or cottage cheese as the centrepiece of each meal rather than an afterthought.

Choose foods that fill you up without tipping the calorie count

Volume matters. Foods that are high in water and fibre — vegetables, salad leaves, berries, soups — take up space in the stomach for relatively few calories. Pairing these with a protein source is a well-established strategy for staying satisfied within a deficit. For practical ideas on using seeds and high-fibre foods to support this, see our guide on eating flax seeds for weight loss.

Keep portions visible and consistent

Reduced appetite can occasionally lead to under-eating — skipping meals altogether or grazing rather than eating structured ones. Both patterns can work against sustained results. A rough awareness of portion sizes and daily intake helps you stay in a moderate, consistent deficit rather than swinging between too little and too much. For broader context on achieving and maintaining a deficit day-to-day, the guide on how to be in a calorie deficit covers the practical foundations in detail.

Avoid the common trap: too few calories

A deficit that is too steep — often the result of relying on reduced appetite alone without tracking — can lead to fatigue, nutrient gaps, and muscle loss. General guidance commonly suggests a moderate deficit of around 300–500 calories below maintenance as a sustainable range, though the right level for any individual depends on their size, activity, and health history. Your prescriber or doctor is the right person to advise on personal targets.

Knowing you should eat in a deficit and actually keeping track of it are two different things — especially when appetite signals are less reliable than usual. GLP Trackr's AI food photo scan makes logging meals almost effortless: point your camera at your plate and the app estimates calories, protein, and macros in seconds, with no manual searching required.

You can also set a daily calorie target and a protein goal, so at a glance you can see where you are against your numbers — whether you've eaten enough protein or have room for a snack later. The app's meal plans and recipe library feature GLP-1-friendly options built around protein and gentle-on-the-stomach ingredients, so you're never staring at a blank page wondering what to cook.

Over time, the insights feature can show you how your food patterns connect to your weight and energy trends — useful information to bring to your next prescriber appointment alongside your progress data. You can explore the full picture of managing your calories and deficit in our calorie deficit hub.

GLP Trackr doesn't replace the guidance of your healthcare professional — your prescriber or doctor knows your full history and is the right person to advise on your personal calorie needs. The app is here to make tracking simpler and keep you consistent.

Give it a try: snap your next meal with GLP Trackr and let the AI do the maths. Available free on the App Store and Google Play, with a 7-day trial to explore every feature.