How the App Sets Your Macros From Your Goals

When the app hands you a macro target, it can feel like it was pulled from thin air. It was not. There is a short, transparent chain of decisions behind it, each one based on well-established nutrition science rather than guesswork. Understanding that chain does two things: it tells you why your numbers are what they are, and it shows you what to change when your goal or your body changes. This is the whole recipe, in the order the app runs it.

The short version

The app estimates your daily energy need from your weight, height, age, and sex, then scales it up for how active you are.
It applies your goal by adjusting calories: a deficit for fat loss, a small surplus for muscle gain, or maintenance to hold steady.
It sets protein first, around **1.6 to 2.2 grams per kilogram** of body weight, because protein is what protects and builds muscle.
It sets fat next, usually 0.6 to 1 gram per kilogram, to support hormones and keep meals satisfying.
Whatever calories are left become carbohydrate, your main training fuel. Change your goal and the whole chain recalculates.

Step one: estimate how much energy you burn

Everything starts with your total daily energy expenditure, the number of calories you burn in a typical day. The app estimates the biggest piece of this, your resting metabolic rate, using a well-validated formula called the Mifflin-St Jeor equation. It takes your weight, height, age, and sex and predicts the energy you would burn at complete rest.

Resting is only part of the story, so the app multiplies that figure by an activity factor based on how much you move and train. Someone with a desk job who trains twice a week gets a smaller multiplier than a labourer who trains six times. The result is a realistic estimate of your maintenance calories, the amount that keeps your weight stable.

Why an estimate, not a fact

Every formula is a starting point, not a lab measurement. Two people with identical stats can burn meaningfully different amounts. The app uses your logged weight trend over the following weeks to correct the estimate, so the first number is a smart opening bid, not the final word.

Step two: apply your goal to the calories

Maintenance calories are the pivot. Your goal decides which way the app moves from there, and by how much. This is the single most important lever, because calorie balance is what actually drives weight change.

Goal	What the app does	Typical shift
Lose fat	Sets a moderate calorie deficit	About 15 to 25 percent below maintenance
Maintain	Keeps calories at maintenance	No change
Build muscle	Sets a small calorie surplus	About 5 to 15 percent above maintenance

The app leans toward moderate adjustments on purpose. A savage deficit costs you muscle and is miserable to sustain, and a huge surplus just adds fat you will have to lose later. A moderate deficit or a lean surplus is slower on paper but far more effective in the real world, because you actually stick to it.

Step three: lock in protein and fat

Once the calorie target is set, the app divides it into macros in a deliberate order. It sets protein and fat as fixed anchors first, because both have jobs that do not scale with leftover calories.

Protein comes first

Protein is the priority macro because it protects muscle in a deficit and builds it in a surplus. The app sets it from your body weight, typically in the range of 1.6 to 2.2 grams per kilogram, which is where the research shows benefits for building and keeping muscle. It nudges toward the higher end when you are losing fat, because protein matters most exactly when calories are scarce.

Fat comes next

Dietary fat supports hormone production and helps you absorb certain vitamins, and it makes food taste good and stay satisfying. The app sets it at roughly 0.6 to 1 gram per kilogram of body weight, enough to cover those needs without crowding out the carbohydrate that fuels your training. Very low fat diets tend to be hard to enjoy, and very high fat ones leave little room for carbs, so the app aims for a workable middle.

Step four: fill the rest with carbs

Carbohydrate is set last, and for a good reason. Once protein and fat have claimed their calories, whatever is left in your budget becomes carbs. This is not a demotion. Carbs are your main fuel for hard training, they help you recover, and they make higher-effort sessions feel better. Setting them last simply means they flex to fill the space rather than fighting the two macros with fixed jobs.

Start with total calories. The goal-adjusted number from step two is the budget everything has to fit inside.
Subtract protein. Protein provides 4 calories per gram. The app multiplies your protein grams by 4 and takes that off the budget.
Subtract fat. Fat provides 9 calories per gram. That comes off the budget next.
Convert what remains to carbs. Carbs also provide 4 calories per gram, so the app divides the leftover calories by 4 to get your carbohydrate target.

A worked example

For an 80 kg person on a 2,200 calorie fat-loss target: protein at 2 g/kg is 160 g (640 calories), fat at 0.8 g/kg is 64 g (576 calories). That leaves 984 calories for carbs, which is about 246 g. Change the weight or the goal and every number here shifts automatically.

Why your numbers change over time

Your first target is a hypothesis, not a life sentence. The app watches what actually happens and adjusts. If you set out to lose fat but your weight has not moved in a couple of weeks, your real maintenance was lower than the estimate, so the app trims calories. If you are gaining faster than intended, it eases the surplus.

You lose or gain weight, which changes your resting burn and your protein target, so the grams move with you.
Your training load shifts, so a heavier block earns more carbs and a rest week needs fewer.
Your goal changes, for example switching from fat loss to maintenance, which resets the whole chain from step two.
Your logged trend disagrees with the estimate, the most powerful correction of all, because real data beats any formula.

This is why the app is not a one-time calculator. The maths above runs once to give you a sensible starting point, then your own results steer it from there. The formula opens the conversation, and your weight trend has the final say.

Questions people ask

Why did the app give me a different number than an online calculator?

Most calculators use the same core formula, but they differ in the activity multiplier they apply and the size of the deficit or surplus they assume. The app also refines its estimate using your logged weight trend, which a one-off calculator cannot do. The starting numbers may differ slightly, but after a couple of weeks of data the app's target is tuned to you specifically.

Why is protein set from my body weight rather than a percentage of calories?

Because your muscle does not care about percentages, it responds to grams relative to your size. Setting protein as a percentage of calories means it drops exactly when you cut calories, which is the worst time to lose protein. Anchoring it to body weight keeps your protein steady while your calories flex, which protects muscle during fat loss.

Can I change the macros the app suggests?

Yes. The targets are a well-reasoned default, not a rule. If you feel better on more carbs and less fat, or you have a preference the science leaves open, you can adjust the split while keeping total calories and protein where they belong. The app cares most that you hit your calories and protein, the two levers that drive results.

How often should I recalculate my macros?

You rarely need to do it by hand, because the app adjusts as your weight and training change. As a rule of thumb, revisit your targets when your body weight has moved by around 5 to 10 percent, when your goal changes, or when progress stalls for two to three weeks despite consistent logging.

References

Mifflin MD, St Jeor ST, et al. The American Journal of Clinical Nutrition. A new predictive equation for resting energy expenditure in healthy individuals. 1990. doi.org/10.1093/ajcn/51.2.241
Morton RW, et al. British Journal of Sports Medicine. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. 2018. doi.org/10.1136/bjsports-2017-097608
Aragon AA, et al. Journal of the International Society of Sports Nutrition. International society of sports nutrition position stand: diets and body composition. 2017. doi.org/10.1186/s12970-017-0174-y

Last reviewed 18 July 2026. We check health-condition articles against current guidelines and update the date above when we do.