How Can You Count Calories? A Practical, No-Fuss Guide

Every food contains a certain number of kilocalories (kcal), which represent the energy it provides. Counting calories means adding up the kcal in everything you eat and drink across the day, then comparing that total to a rough daily target. Here is how to do it in practice.

1. Establish a rough daily calorie target

A daily calorie target depends on factors including your height, weight, age, sex, and activity level. General guidance suggests that many adults need somewhere in the range of 1,500–2,500 kcal per day, but individual needs vary considerably. For personalised guidance, speak with your prescriber or doctor. If you want to understand the underlying calculation, our guide on eating in a calorie deficit explains the principles clearly.

2. Read nutrition labels and use a food database

Packaged foods carry nutrition labels listing kcal per 100 g and per serving. For unpackaged foods — fruit, vegetables, meat, home-cooked dishes — a reliable food database gives you the values you need. Most databases let you search by food name and adjust the portion size to match what you actually ate.

3. Weigh or measure your portions

Label figures are based on a stated serving size, which often differs from what ends up on your plate. A kitchen scale (or, for liquids, a measuring jug) takes the guesswork out of portions and makes your logs much more accurate. Even a few weeks of weighing food can sharpen your ability to estimate portions by eye later on.

4. Log consistently, not perfectly

Accuracy matters more than perfection. Logging most meals, most days, gives you far more useful data than logging precisely for three days and then stopping. Many people on Mounjaro or Wegovy find appetite fluctuates week to week — a consistent log makes it easier to spot when intake has drifted. For more detail on the process, see how to count calories step by step and counting calories specifically for weight loss.

How do you count macros alongside calories?

Macronutrients — protein, carbohydrates, and fat — are the three components that make up your calories. Protein provides roughly 4 kcal per gram, carbohydrates roughly 4 kcal per gram, and fat roughly 9 kcal per gram. Counting macros simply means tracking how many grams of each you eat, in addition to the total kcal. On a GLP-1 journey, protein tends to get particular attention because it helps preserve muscle mass and supports satiety when overall intake is lower. You can read more in our companion guide on making calorie counting manageable day to day.

The single biggest barrier to counting calories is the friction of logging — especially on days when appetite is low and meals feel unpredictable. GLP Trackr's AI photo scan addresses that directly: point your camera at a meal and the app returns an instant calorie and macro breakdown, with no manual searching required. It is particularly useful when you are eating smaller, less structured meals, which is common on a GLP-1 medicine.

Beyond photo scanning, you can also log foods by barcode or search, and set personal targets for calories, protein, fibre, and water so you can see at a glance how your day is tracking. The app brings your food data together with your weight log and daily check-in, so over time you can see how your eating patterns relate to your progress — the kind of joined-up picture that is hard to build from a spreadsheet or memory alone.

GLP Trackr is built specifically for people on Mounjaro and Wegovy, so the meal plans and recipe library are designed around the practical realities of GLP-1 appetite: protein-first, gentle-on-the-stomach options with easy swaps for days when certain foods do not appeal.

If you want to understand how your calorie target fits into your broader weight goal, the calorie deficit guide is a good next step.

Ready to make logging feel less like a chore? Download GLP Trackr on the App Store or Google Play — your first 7 days are completely free.