How many calories you need in a day
Every calculator gives you a number. Very few explain what it is built on, how wrong it can be, and what to do when the scale disagrees with it two weeks later.
BMR
What your body spends at complete rest — the largest and most stable part of the total.
Activity
A multiplier for movement and training. The most common place people overestimate.
Deficit
The gap that makes weight go down. Bigger is not better — it is just harder to keep.
Macros
How the target splits into protein, fat and carbs once the calorie number is set.
Where the number comes from
Basal metabolic rate is estimated from your sex, age, height and weight — the Mifflin-St Jeor equation is the usual choice, and it is what Fat Track uses. It is a statistical estimate: for a given person the real figure can sit a few hundred calories either side.
That estimate is multiplied by an activity factor, from sedentary to several training sessions a week. Then a deficit is subtracted if the goal is weight loss. The result is a starting hypothesis, not a physical constant.
How to check the number against reality
- Track for two weeks at the target and watch the weekly average weight, not single mornings.
- Losing faster than roughly 1% of body weight per week usually costs you muscle and adherence — raise the target.
- Not moving at all for two weeks with an honest diary? Lower it by 100–150 kcal rather than by a third.
- Recalculate after every 4–5 kg of change: the same person at a lower weight needs less.
Protein, fat and carbs
Protein is the one worth defending: it keeps you full and protects muscle in a deficit. Fat has a floor below which hormones and satiety suffer. Carbs take whatever is left — they are the flexible part, not the enemy.
In Fat Track the split is computed from your profile and goal, and you can override every number by hand if a coach or a doctor gave you different targets.
Questions
How many calories should I eat to lose weight?
Usually 10–20% below your estimated maintenance. Treat it as a hypothesis: keep the diary for two weeks and adjust by the weekly average weight rather than by the calculator.
Which formula does Fat Track use?
Mifflin-St Jeor for basal metabolic rate, then an activity factor and your chosen deficit. You can override the resulting targets manually.
Do I have to recalculate as I lose weight?
Yes. Every 4–5 kg is a good moment — a lighter body burns less, and a target that worked in month one stalls in month three.
Is a bigger deficit faster?
On paper, yes; in practice it is the main reason people quit and regain. A deficit you can keep for months beats an aggressive one you abandon in two weeks.
Get your targets and start filling them in
Answer a few questions in the bot and it works out calories, protein, fat, carbs, fibre and water for your goal — then every photo you send goes straight into that day.