What are macronutrients, and how do you choose the right proportions?

If you’re searching for “what are macronutrients,” the shortest answer is: protein, carbs, and fat—three nutrients that provide energy and serve different functions in the body. One gram of protein or carbs contains about 4 kcal, while one gram of fat contains about 9 kcal. You can adjust their proportions to fit your goal, but there’s no one ideal split for everyone.

What are macronutrients?

Macronutrients, also called macros, are nutrients we need in relatively large amounts. They provide energy, but that’s not all: protein builds and repairs tissues, fat supports functions such as cell activity, and carbs are an important source of energy.

They’re different from micronutrients, such as vitamins and minerals. The body needs less of these, but they’re still important for health. No macronutrient is inherently “bad”—what matters is your overall diet, its quality, and the amount of food that fits your needs.

What do protein, carbs, and fat do?

Protein provides amino acids needed to build and maintain muscles and other tissues. The body also uses it to make enzymes and some hormones. You can find it in eggs, dairy, fish, meat, tofu, beans, and lentils. For practical guidance on amounts, see our article on how much protein to eat each day.

Carbs are an important source of energy for the body, especially during physical activity. They’re found in foods such as bread, grains, potatoes, rice, fruits, vegetables, and legumes. Carbs aren’t just sugar—whole grains, vegetables, fruits, and legumes also provide fiber.

Fat provides energy, forms part of cell membranes, and helps the body absorb vitamins A, D, E, and K. It’s a good idea to eat a variety of sources, such as olive oil, nuts, seeds, avocados, and fatty fish. Fat is also useful in cooking—for example, for frying or as an ingredient in sauces—but it’s easy to add more than you think.

How many calories are in a gram of protein, carbs, and fat?

That’s why the same number of grams of different macronutrients doesn’t mean the same number of calories. Ten grams of fat provides about 90 kcal, while ten grams of protein or carbs provides about 40 kcal. In practice, the figures on food labels may differ slightly due to rounding and the product’s composition.

Fiber is classified as a carbohydrate, but the body digests it differently from sugars and starch. For energy calculations, it’s often estimated at about 2 kcal per gram. Alcohol isn’t a macronutrient, but it provides about 7 kcal per gram.

What macronutrient ratios should you choose for weight loss or muscle gain?

It’s best to start by choosing a calorie intake that fits your goal. An energy deficit can help with weight loss, while muscle gain usually requires enough energy, often with a slight surplus. Macro ratios alone can’t replace this energy balance. To check your calories, try our macronutrient calculator or read about how a calorie deficit works.

Treat the ranges below as a practical starting point, not a strict prescription. General reference ranges for adults may vary depending on guidelines and individual needs; you can find example reference values in EFSA materials. When choosing specific proportions, make sure they add up to 100% of your energy.

These ranges aren’t meant to be added by choosing all the lowest or all the highest values. Set your protein and fat proportions, then adjust carbs so the total adds up to 100%. For example, in a 2000 kcal diet, getting 25% of energy from protein, 30% from fat, and 45% from carbs means about 125 g, 67 g, and 225 g per day, respectively. This is just an example calculation, not a goal that works for everyone.

For weight loss, focusing on protein may help you feel full and make it easier to maintain muscle, especially if you do strength training. When building muscle, carbs can provide energy for training, while protein provides material for recovery. If you train and want to set your protein intake based on your body weight, see our article on how much protein to eat for muscle gain.

How can you set your macros without making your day complicated?

Start with a calorie intake that suits your goal, then choose amounts of each macronutrient that you can maintain in everyday life. You can use percentages or set your protein in grams and divide the remaining calories between carbs and fat. The second approach can be convenient because your protein target in grams depends not only on your calorie intake, but also on your body weight and activity level.

In practice, it looks like this: choose a protein source for lunch, add potatoes, grains, or bread, then include vegetables and a source of fat. You don’t have to build the perfect plate every time. What matters is the overall picture across the day and week—not whether Friday’s pizza fit perfectly into a spreadsheet.

If you log what you eat, pay attention to servings and labels—nutrition information varies by product and preparation method. In our article how to calculate the macros in a meal, you’ll find a way to assess a specific dish. You can also use EatSee to estimate calories and macros from a photo or a short meal description; you can adjust the result if the serving size or an ingredient has changed.

Do you need to hit the ideal ratios every day?

No. Macros are a tool to help you understand your eating habits, not a test of perfect eating. If you eat more carbs one day and more fat another, that doesn’t undo your progress. What matters more are habits you can maintain and your overall balance over the long term.

Pay attention to the quality of your food, too: choose vegetables, fruit, whole grains, legumes, and a variety of protein and fat sources more often. If you have a chronic condition, are pregnant or breastfeeding, have an eating disorder, or take medication, discuss your calorie and macronutrient targets with a doctor or dietitian. In these situations, a one-size-fits-all chart may not suit your needs.

This article is for informational purposes only and does not replace advice from a doctor or dietitian. Written by the EatSee editorial team. Editorial policy.