Daily Calorie Intake: What to Know When You're on Mounjaro or Wegovy

Calorie needs aren't a single number — they vary from person to person based on several factors. Understanding those factors helps you make sense of the intake figures you'll come across.

The main factors involved

• Biological sex: On average, people assigned male at birth tend to have higher calorie requirements than those assigned female, largely because of differences in muscle mass and body composition. If you want figures tailored to your sex, see our pages on daily calorie intake for men and daily calorie intake for women for more detail.
• Body size and composition: A larger body, or one with more muscle, burns more energy at rest. This is why two people of different heights or weights can have very different advised daily calorie intakes.
• Age: Metabolic rate tends to slow gradually with age, so required daily calorie intake often decreases over the decades.
• Activity level: Someone with a physically demanding job or regular exercise routine needs considerably more energy than someone with a sedentary lifestyle.

How GLP-1 medicines change the picture

Mounjaro (tirzepatide) and Wegovy (semaglutide) commonly reduce appetite and increase feelings of fullness, which means many people find they eat substantially less without trying. This is generally the intended effect — but it also means there's a real risk of eating too little, particularly of protein, which is important for preserving muscle while losing weight.

General guidance from nutrition research suggests that protein intake of roughly 1.2–1.6 g per kg of body weight per day can be helpful when losing weight, though individual needs vary. For a more detailed look at how recommended figures are calculated, visit our page on recommended daily calorie intake.

Eating too little: worth keeping an eye on

A very low calorie intake — particularly one that drops below around 800 kcal per day without medical supervision — can lead to fatigue, muscle loss, and nutritional deficiencies. If you're concerned your intake has fallen very low, speak with your prescriber or doctor. You can also explore how daily calorie needs differ for women or check the specific calorie guidance relevant to women on GLP-1 medicines if that applies to you.

Keeping track of how much you're actually eating is harder than it sounds — especially when appetite is low and meals are smaller and more irregular. GLP Trackr's AI food photo scan is one of the most practical tools here: point your camera at a meal and get an instant breakdown of calories, protein, and macros without typing anything in.

Beyond scanning, you can set a personal daily calorie target and a protein goal, and the app tracks your running totals through the day so you can see at a glance whether you're on track. If you find the numbers easier to interpret when you also have your injection schedule visible alongside your food log, the dose logging feature keeps everything in one place.

Over time, your food data feeds into the app's weekly insights — so you can spot patterns like which days your intake dips lowest, or how your energy and mood scores relate to what you've eaten. That kind of picture is genuinely useful to bring to your next appointment. For context on how your calorie needs fit into a broader weight-management approach, our guide to managing a calorie deficit on GLP-1 medicines covers the bigger picture.

Always follow the guidance of your prescriber or doctor on calorie targets — they know your full health history and can give you a figure that's right for you specifically. GLP Trackr helps you record what you eat so those conversations are grounded in real data, not guesswork.

Ready to start logging? Download GLP Trackr on the App Store or Google Play and explore it free for 7 days — no commitment needed.