Macros is short for macronutrients: the three nutrients your body needs in large amounts, which are protein, carbohydrate and fat. Together they make up almost all the calories in your food. "Counting macros" simply means tracking how much of each you eat, rather than just the total calories.
It's popular in gyms and on social media, but whether it's worth the effort depends on your goals. Here's what each macro does, what UK guidance suggests, and when tracking helps.
The three macros
| Macro | Calories per gram | Main job | Common sources |
|---|---|---|---|
| Protein | 4 | Builds and repairs muscle and other tissue | Meat, fish, eggs, dairy, beans, lentils, tofu |
| Carbohydrate | 4 | Main source of energy, especially for the brain and exercise | Bread, rice, pasta, potatoes, oats, fruit |
| Fat | 9 | Hormones, absorbing vitamins A, D, E and K, long-lasting energy | Oils, nuts, seeds, oily fish, avocado, cheese |
Alcohol also provides energy, at about 7 calories per gram, but it isn't counted as a macro.
What UK guidance says
UK dietary recommendations are expressed mostly as shares of your total energy rather than strict gram targets:
- Carbohydrate: around half of your food energy, with fibre aiming for 30 g a day and free sugars kept low
- Fat: no more than about a third of your food energy, with saturated fat kept to around 11% or less
- Protein: the reference intake for adults is 0.75 g per kg of body weight a day, and many active people and people building muscle aim higher
Our guide to how much protein you need per day goes into the protein figures in more detail.
A worked example
Say someone eats 2,000 kcal a day and chooses a split of 25% protein, 45% carbohydrate and 30% fat. This is only an illustration, not a recommendation:
| Macro | Share | Calories | Grams |
|---|---|---|---|
| Protein | 25% | 500 | 125 g |
| Carbohydrate | 45% | 900 | 225 g |
| Fat | 30% | 600 | about 67 g |
Grams are worked out by dividing the calories for each macro by its calories per gram: 500 ÷ 4 = 125 g of protein, 900 ÷ 4 = 225 g of carbohydrate, and 600 ÷ 9 = about 67 g of fat. The macros calculator does this for you from your own details.
Should you count macros?
It can be worth it if you...
- Are building muscle and want to reliably hit a protein target
- Have a specific training or performance goal
- Have been advised to by a dietitian or doctor
- Have been stuck for a while and want to see where your calories really come from
You can probably skip it if you...
- Are just aiming for generally healthier eating
- Find that logging every meal feels stressful or takes over your day
A simple way to start
- Work out your calories with the calorie calculator
- Set your protein first, using the guidance above or your goal
- Keep fat in a sensible range, around 25–35% of calories for most people
- Let carbohydrate fill the rest of your calories
- Check in after two to three weeks and adjust based on energy, hunger and results
Need ideas for hitting a protein target? See our best protein sources in the UK and high-protein meal ideas.
The bottom line
Macros are just protein, carbohydrate and fat. Understanding them helps you eat in a more balanced way, and tracking them is a useful tool for some goals but not a requirement for everyone.
Sources: NHS Eatwell Guide, UK government dietary reference values. This page is for general information and is not medical advice. If you have a medical condition or specific dietary needs, speak to your GP or a registered dietitian.