Every calculator gives you a number. None of them tell you where it stops.
Maintenance, deficit, protein floor, rate of loss — the four numbers, each one broken into the terms it came from. Then the part the others skip: your maintenance falls as your weight does, so a fixed intake stops working long before the straight line says.
Basal rate — kcal, multiplied by — for —. That is what you burn on an average day at your current weight — not a target, just the line you are eating above or below.
Twenty-six weeks, if you eat this every day
Where each number comes from
- Basal rate is Mifflin-St Jeor: 10 × kg + 6.25 × cm − 5 × years, then +5 for men and −161 for women. The four terms are listed above so you can add them up yourself.
- The multiplier is a base for the rest of your day — 1.15 desk, 1.30 on your feet, 1.45 physical work — plus 0.05 for each training day. Four sessions at a desk job gives 1.35. These are conventional bands, not measurements of you.
- The target is maintenance −20% to lose, +12% to gain, or maintenance itself to hold.
- Protein is 2.2 g per kg when losing and 1.8 g when gaining or holding, then capped at 40% of the day's calories — without that cap a heavy person in a deficit gets handed a negative carb number.
- 7,700 kcal per kg is the conventional figure for body fat (3,500 per pound). It is a rule of thumb, not a constant: early weeks move faster because of water, and not all of a deficit comes out of fat.
- The solid line recomputes basal rate from your new weight each week and feeds it back in. The dashed line does not — it just repeats week one forever. That is the only difference between them, and it is why they separate.
- The settling point is where the two sides meet: the weight at which maintenance equals the intake you are holding. Solve (10 kg + 6.25 cm − 5 age + s) × multiplier = intake for kg. At a steep deficit that answer often lands far below any sane weight — the arithmetic keeps going where the formula stopped meaning anything. It is there to show you the deficit closes itself, not to give you a target.
- Nothing here is measured. No body-fat percentage, no metabolic testing, no record of what you actually ate. Two people with identical inputs can differ by several hundred kcal a day, and none of this accounts for the slowdown that comes from dieting itself. Treat every number as a starting estimate to correct against the scale, redo it every few kilos, and take medical questions — including whether a deficit is a good idea for you at all — to someone who can examine you.
This is general information, not medical or dietary advice. Every figure on this page comes from a population formula, and conditions such as thyroid disease, diabetes, kidney or liver disease, eating disorders, pregnancy and a long list of medications change what is appropriate. If any of those apply, the numbers that count are the ones your doctor gives you.