How to Work Out Your Macros for Weight Loss

Macronutrients provide calories: protein and carbohydrates each deliver around 4 calories per gram, while fat provides around 9 calories per gram. When you are working towards weight loss, the total calories you consume matters most — but the macro split shapes how sustainable that deficit feels day to day.

The three macros and why they matter

• Protein supports muscle preservation during weight loss and is the most satiating macronutrient, meaning it helps you feel fuller for longer. On a GLP-1 medicine, where appetite is already reduced, hitting a protein target becomes especially important to protect muscle mass.
• Carbohydrates are the body's primary fuel source. Choosing higher-fibre carbohydrates (vegetables, legumes, wholegrains) tends to support steadier energy levels and digestive comfort.
• Fat is essential for absorbing fat-soluble vitamins and producing hormones. Very low-fat diets are rarely recommended for long-term weight management.

How to determine your macros for weight loss

A common approach is to start from your total daily energy expenditure (TDEE) — your estimated calorie needs at your current activity level — and apply a moderate calorie deficit, then allocate macros within that. A widely used general framework looks like this:

• Protein: 30–40% of total calories (or anchor to a gram-per-kilogram target)
• Fat: 25–35% of total calories
• Carbohydrates: the remainder

These are general educational ranges, not a personal prescription — a registered dietitian or your prescriber can help you refine targets for your specific health situation. For a step-by-step calculation, see the guide to calculating your macros, or run the numbers directly with the macros calculator.

Do macro needs differ for women?

Broadly, the principles are the same regardless of sex, but calorie and protein targets will naturally vary based on body weight, lean mass, and activity level. Someone with a lighter body weight will generally have a lower absolute protein target in grams, even if the ratio per kilogram is identical. The nutrition macros overview covers this in more detail.

Working out your macros on paper is useful, but hitting them consistently every day is where most people find it difficult — especially when appetite fluctuates on a GLP-1 medicine and meals can feel unpredictable. GLP Trackr makes the daily tracking part effortless.

The app's AI food photo scan is the fastest way to log what you eat: point your camera at a meal and the app returns an instant breakdown of calories, protein, carbohydrates, and fat — no manual searching required. For packaged foods, the barcode scanner pulls nutrition data in seconds.

Once your targets are set inside the app, you can see at a glance how your protein, calories, and other macros stack up against your goals each day. The targets feature lets you track protein, calories, fibre, and water in one place — useful when you are managing smaller, more frequent meals around reduced appetite.

For broader context on how your food choices are connecting to your progress, the calorie calculator hub brings together the tools and information that support your GLP-1 journey.

Macro targets shown in the app are general tracking guides. For personalised nutrition advice — especially if you have any health conditions — speak with your prescriber or a registered dietitian.

Ready to stop estimating and start actually hitting your targets? Download GLP Trackr on the App Store or Google Play and explore all the tracking features free for your first 7 days.