Macros are the three nutrients the body uses for energy: protein, carbohydrate and fat. "Macro" is short for macronutrient — macro because you eat them in grams, where vitamins and minerals are measured in milligrams. A macro target is a daily gram figure for each of the three.
Calories are not a fourth macro. Every calorie comes from one of the three, or from alcohol, so the calorie total and the macro split are the same information described two ways.
What each macro does
| Macro | Calories per gram | What it is mainly for |
|---|---|---|
| Protein | 4 | Building and retaining muscle, repair, and keeping a client full on fewer calories |
| Carbohydrate | 4 | Fuel for training, particularly hard or high-volume sessions |
| Fat | 9 | Hormone production and absorbing vitamins A, D, E and K |
Fat carries more than twice the energy of the other two per gram, which is why a client can eat a large volume of food and stay under target, or a small amount and go well over.
Alcohol sits at 7 calories per gram. It is not a macro, since the body has no requirement for it, but it still counts towards the day and clients routinely forget to log it.
Fibre is a carbohydrate the body cannot digest for energy. It sits inside the carb total and is worth its own rough daily target.
Work out the calorie number before the split
Macros only make sense once you have a calorie target, because the split is a division of that number. The starting point is the client's total daily energy expenditure, of which deliberate exercise is a smaller share than most clients assume. Much of the gap between two clients who look identical on paper is non-exercise activity, which drops on its own during a diet and is a common reason a target that worked in week two stops working in week eight.
A calculator gives an estimate, not an answer. Turning that estimate into a working number, and then into grams, is covered in how to calculate TDEE and macros for clients.
Why coaches set a target for each macro
You could give a client one calorie number and leave the rest to them. Most coaches do not, for three reasons.
Protein has a floor. Two clients eating 2,000 calories in a deficit hold very different amounts of muscle depending on whether protein is 80g or 160g, and protein is also the macro that keeps people full. Ranges by goal and body weight are in how to set protein targets for clients.
Fat has a floor too. Cut it too far and you get the hormonal and mood complaints that end diets early. Most coaches set a minimum and leave headroom above it.
Carbohydrate is what is left. The remaining calories go to carbs, the macro training performance responds to most directly, and raising or lowering them is usually the first adjustment when a client is flat in sessions.
That is the whole logic: set protein, set a fat minimum, fill the rest with carbs, then adjust the calorie total on what the scale and the check-in data do over a few weeks. In Fitsly you set each macro in grams or as a percentage of the calorie goal, with a variance band that decides how close counts as on target, and date overrides for the days a client is travelling or eating out.
What macro targets do not tell you
A day that hits every macro can still be three protein bars and a bowl of pasta. Macros say nothing about micronutrients, fibre or food quality. They are an energy and composition tool, not a measure of a good diet.
They are also not a plan a client can execute on day one. Tracking is a skill, and clients handed four numbers without being taught to weigh and log food report figures that are wrong in a consistent direction — usually low. A staged approach is in how to teach clients to track macros.
Macros are also general nutrition information. Clients with diabetes, an eating disorder history or a prescribed diet belong with a dietitian or their doctor, and any targets you set should follow that advice rather than replace it.
