Macros Explained: Protein, Carbs and Fat Without the Jargon

“Macros” is short for macronutrients: protein, carbohydrate and fat, the three parts of food that supply calories. Protein and carbohydrate provide about 4 calories per gram, fat about 9, and alcohol, which is not a nutrient but still counts, about 7. Your total calories decide whether you gain or lose weight. Your macros decide much of what that weight is made of, how you feel and how well you train. For most people who lift, the practical order is: get protein right, keep fat at a sensible level, and let carbohydrate fill the rest according to how active you are.

Calories and macros: how they fit together

Think of calories as the budget and macros as how you spend it. You can lose fat on a diet of mostly carbohydrate or mostly fat, as long as you are in an energy deficit over time. But the same calorie total split in different ways will give you different results in muscle retention, hunger, energy in the gym and how easy the plan is to keep. If the budget side is new to you, start with what a calorie deficit is, then come back here.

Macro	Calories per gram	Main job	Common sources
Protein	About 4	Building and repairing tissue, including muscle; very filling	Meat, fish, eggs, dairy, tofu, beans, lentils
Carbohydrate	About 4	Main fuel for hard training; fibre for gut health	Potatoes, rice, oats, bread, pasta, fruit, pulses
Fat	About 9	Hormone production, absorbing fat-soluble vitamins, cell structure	Oils, nuts, seeds, oily fish, avocado, dairy, meat
Alcohol	About 7	None nutritionally; still counts towards total energy	Wine, beer, spirits

Protein: the one to get right first

Protein supplies the amino acids your body uses to build and repair muscle. If you train with weights, eating enough of it is what lets that training turn into muscle, and in a fat-loss phase it helps you keep the muscle you already have. It is also the most filling macro per calorie, which makes a deficit easier to live with.

The UK reference intake for the general population is set for basic needs rather than for people who train. For those lifting regularly, a commonly used target in sports nutrition research is roughly 1.6 grams per kilogram of body weight per day, with some benefit up to about 2.2 grams in a deficit. I go into the detail, and how to spread it across meals, in how much protein to build muscle. If you have kidney disease, check with your GP before raising protein substantially.

Carbohydrate: fuel, not the enemy

Carbohydrate is your body’s preferred fuel for hard, repeated efforts, the sort you do in a strength session or an interval workout. It is stored in muscle and liver as glycogen. Low-carbohydrate diets can work for fat loss, mostly because they cut out a lot of easy-to-overeat food, but many people find their training suffers.

The NHS Eatwell Guide suggests starchy carbohydrates should make up just over a third of the food you eat, with higher-fibre wholegrain versions where possible. Fibre is the overlooked part of carbohydrate: adults are advised to aim for 30 grams a day, and most people in the UK eat well under that.

A sensible way to think about it

• On training days, put more of your carbohydrate in the meals before and after the session.
• Choose sources that also bring fibre: oats, potatoes with skins, wholegrain bread, beans, fruit.
• If you are less active one day, carbohydrate is the macro to trim, not protein.

Fat: necessary, just dense

Fat is essential. You need it for hormone production and to absorb vitamins A, D, E and K. The issue is simply density: at 9 calories per gram, a generous glug of olive oil or a handful of nuts adds up quickly without filling you much. That is not a reason to avoid fat, just to be aware of portions.

Most of your fat should come from oils, nuts, seeds, oily fish and avocado. The NHS advises limiting saturated fat, the kind found in butter, cream, fatty meat, pastry and cakes. A practical floor is to avoid letting fat drop very low for long periods; diets with extremely little fat tend to be hard to sustain and can leave people feeling flat.

How to set your macros in four steps

1. Estimate your calories. Start from maintenance, then subtract for fat loss or add a little for muscle gain. The method is in working out maintenance calories.
2. Set protein. Roughly 1.6 to 2.2 grams per kilogram of body weight. Multiply grams by 4 to get calories.
3. Set fat. A common starting range is 25 to 35 percent of total calories. Divide those calories by 9 for grams.
4. Fill the rest with carbohydrate. Whatever calories remain, divide by 4.

A worked example

Take someone weighing 80 kg aiming for 2,200 calories a day. Protein at 2 g/kg is 160 g, or 640 calories. Fat at 30 percent is 660 calories, about 73 g. That leaves 900 calories for carbohydrate, or 225 g. That is a reasonable, sustainable starting point for someone training three or four times a week. Then adjust over two or three weeks based on your weight trend, hunger and how training feels.

Do you actually need to count macros?

Not always. Counting is a tool, and like any tool it is worth using only if it pays for itself. It is most useful when:

• You have stalled and want to see what you are actually eating.
• You are preparing for a specific event and want precision for a few months.
• You suspect protein is low but are not sure.

It is less useful if it makes eating stressful, or if you travel and eat out so often that numbers are guesses anyway. A middle route is to count protein only, or to track carefully for two weeks to calibrate your eye, then switch to portion habits. In private training sessions in Highgate, this is usually how we approach it: enough structure to make progress, not so much that it takes over your week.

Mistakes that make macros harder than they need to be

• Chasing perfect numbers daily. Weekly averages matter more than hitting every gram.
• Forgetting cooking oils and drinks. Both carry significant calories and are easy to miss.
• Cutting carbohydrate first when training hard. It often shows up as worse sessions within a week.
• Treating protein bars as health food. Some are fine; many are confectionery with extra protein.
• Ignoring alcohol. It has no macro category in most apps, but still counts.

Questions we get asked

What is the best macro split for fat loss?

There is no single best split. Keep protein high, fat moderate, and adjust carbohydrate to fit the calorie target. Consistency matters far more than the precise percentages.

Do macros matter if calories are right?

For weight change, calories matter most. For keeping muscle, managing hunger and training well, protein and carbohydrate intake matter a lot.

Should I eat fewer carbs in the evening?

Timing matters far less than daily totals for most people. If you train in the evening, carbohydrate afterwards is perfectly sensible.

Can a trainer help with nutrition?

A trainer can give general, evidence-based guidance on eating to support training. For medical conditions, see a registered dietitian. More on how coaching works on the personal training page at The Highgate House.

---

Book with The Highgate House

Ready to start training properly? Email us at [email protected] with the service and the day that suits you, and we will come back to you with times.

Visit The Highgate House · Private personal training

The Highgate House, Archway Road, Highgate, London N6.