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Macros: the big 3 of nutrition


80% of nutrition comes from counting how 3 nutrients add up: protein, fats, and carbs. These are the macronutrients and they do tons of work in your diet.

Today we’re discussing these crucial, ‘big’ players in your diet and what you need to know about them. We’ll be looking at examples, how to think about them, and giving you the tools you need to start understanding the relationship between nutrients and nutrition.


Macros: What are they and why are they important?

Macronutrients are the major calorie-sources in your diet. By getting to grips with them and tracking them you can accurately predict your calorie intake – as well as the effect these nutrients will have on your body.

This is the foundation of better nutrition, which is followed by the more detailed tweaks that take you from understanding to mastery.

When you get a better handle on these 3 nutrients, you can better-control your diet and body. It also helps you get the most from exercise and other factors, which feed off of the resources that nutrition provides your body.

This is more than just controlling your bodyweight: it contributes to metabolic health, digestive wellbeing, energy levels through the day, and your risk of various health conditions. Mastering the macros accounts for a huge amount of dieting success and health.



Proteins are chains of amino acids that are broken down and then recombined to provide you with the building blocks of many important tissues.

Muscles are made up of proteins (things like actin and myosin), while bones and tendons rely on protein to build collagen. This pattern repeats all over the body – which is why protein is the most important nutrient.

If you don’t get it from your diet, your body will scavenge these raw materials from muscles, tendons, and other sources. This can lead to tissue breakdown and lead to higher injury risk, reduced exercise performance, and even loss of bone density (a major osteoporosis risk).

Protein intake is usually best treated as “more is better”, within reasonable terms. You should get a minimum of 0.6g per kg of bodyweight, all the way up to 2.2g per kilo – which helps support muscle growth, strength, and health when undergoing intense exercise.

The amino acids that make up proteins are individually important. Some of them are essential (you can’t produce them from other amines or proteins). Unsurprisingly, they’re called essential amino acids (EAAs) and are both important for muscle growth and proper metabolic function.

Make sure that your protein sources are either complete (like animal products, high-quality cultured dairy, and seitan) or come from varied sources. Vegetarians and vegans need special focus on these EAAs and to ensure you’re pairing the right protein sources to cover all your essential amino acids.

A few examples:

  1. Meats: beef, venison, and others
  2. Poultry: chicken, turkey, and others
  3. Eggs
  4. Fish and seafood
  5. Cultured dairy: low-fat Greek yoghurt, hard cheeses, and others
  6. Beans: mung, black, and others
  7. Seitan and other grain-proteins
  8. Supplements: whey, casein, and others


Carbs are short-term fuel. They’re the compounds in foods that are rapidly converted into glucose. Your body uses glucose for a wide range of purposes and specifically spares it for use in the most important short-term organs like the brain and liver.

Carbs are primarily stored in the muscles, too, where they make up your energy stores. They’re closely related to short, explosive bursts of energy and slowly taper out as you extend the duration of exercise: longer durations lean more towards fats and less towards carbs.

Carbs break down into sugars, starches, and fiber. There’s some important chemistry behind this but the rule of thumb is that this is a spectrum of simplicity and digestibility.

Sugars are simple and rapidly digest, while starches are usually more complex and slower-digesting, and then fiber is non-digestible.

Sugars are very-short-term energy and should be used mainly before, during, and immediately after exercise to fuel up. Starches can be great for normal use and feeding for the hours ahead, especially when they’re in a mixed source with fiber (such as oatmeal).

Fiber is a key part of your metabolic and digestive health where it binds to carbs and water in the gut. It also slows overall digestion to reduce “dumping” energy into the bloodstream and regulates the release of things like insulin.

Each carb category has its place in a diet. While sugar intake should be monitored, it’s a good example of how you need to balance intake to use.

Sugar during exercise is a great way to regulate energy levels and improve performance. Starches are for regular feeding, especially in sources like beans and oatmeal where they’re mixed with fiber and a wide variety of vitamins and minerals.

A healthy diet just comes from shifting your priorities away from sugar and towards starch. The best carb sources are rich in other nutrients and not just carbs (which is why heavily-refined and heavily-processed carbs are so closely associated with poor nutrition).

Carb intake should be closely set out along with 2 major factors:

  1. How much muscle mass do you have? More muscle = more baseline carbs
  2. How much activity do you do? More activity = more carbs above baseline

These are the 2 key factors that we use to make sure carb intake is set out properly. It’s how we support muscle mass (carb restriction can limit muscle growth or induce muscle loss) and should both the quantity and type should be set around your activity schedule.

More carbs for more physical work and short-term carbs (sugary or simpler) closer to exercise, while outside of exercise you focus on slow-digesters like beans, wholegrains, tubers, and high-quality veggies.

These occur on a 3-6g per kg of bodyweight scale. 3g/kg for sedentary people and 6g/kg for highly-active high-intensity exercisers. Find yourself somewhere on this scale and see what fits your needs.

A few examples:

  1. Oatmeal
  2. Beans and pulses: beans, quinoa, and others
  3. Tubers: potatoes, sweet potatoes, and others
  4. Buckwheat and other (cooked) pseudo-cereals
  5. Beets and other root vegetables
  6. Berries (especially dark ones and blueberries)
  7. Squashes: pumpkin, aubergine, and others
  8. Peas and associated starchy greens


Dietary fats don’t get as much love because they’re both required in smaller amounts and more calorie-dense.

While protein and carbs are 4 calories each, fats are 9 per gram. This makes over-eating on fats (usually in other foods, like baked goods) much easier. Fats don’t make you fat, but over-eating them definitely will.

Fats also contribute to better lower-intensity, higher-duration exercise. If you’re in a sport or hobby like running or swimming, you want to make sure fats are well-represented in your diet to keep up your fat-metabolism function.

Dietary fats, because they’re a smaller part of the diet, should be selected for quality. They break down into saturated, monounsaturated, and polyunsaturated.

Common approaches simply suggest eating priority-unsaturated fats. Here’s a handy rule of thumb you can use to keep your dietary fats well-balanced:

  • saturated fats should typically be no more than 1/3 of daily fats
  • monounsaturated fats around 1/3
  • polyunsaturated fats should be at least 1/3

Focus on quality, as mentioned: more MCT oils and coconut oils for your saturated fats, more fish oils (from food and supplementation), and high-quality oils like olive oil. The better your representation of these key fats, the better your diet will work overall.

  1. Olives and their oil
  2. Avocados and their oil
  3. Fish and Seafood (rich in Omega-3 fats)
  4. Grass-fed meats: beef, venison, and game
  5. Nuts and seeds
  6. Cultured dairy: yoghurt, real cheeses, and others
  7. Coconut oil
  8. High-quality eggs

Final Thoughts: putting it all together

These are the absolute basics of diet, and they aren’t as inaccessible as many people think.

Tracking is one way of getting into this kind of information and using it to better-understand what is in foods and where your calories are coming from.

The better you understand these nutrients and the more high-quality staples you have in your diet, the easier it is to be healthy in a delicious and performance-boosting way.

Macronutrients help us understand what makes up food and the energy, environment, and resources we provide our body. Your diet can be enjoyable, healthy, and support your exercise or sporting goals all at once with proper management. It doesn’t have to be penance.

Sian Baker

Medically reviewed by Sian Baker, Dip ION mBANT mCNHC – Written by Beth Giddings.

Updated on 1st December 2021