Weight-loss pace and time to goal

Pick a pace as a share of your weight — the way the step on pace recommends — and see what it means in kilograms, in calories and in weeks. Everything is computed in your browser.

Half a kilogram a week is a gentle pace for a 120-kilogram person and a hard one for a 55-kilogram person. The same share — half a percent — means roughly the same thing to both: the same fraction of the body's stores going per week, and a similar strain. That is why the app plans in shares of trend weight and why its ceiling is one percent a week for everyone, rather than a fixed number of kilograms that would be brutal for the light and trivial for the heavy.

What the calculator does

For each week it takes the chosen share of the current weight and turns it into a daily deficit using an estimate of what a kilogram of your loss is worth in energy: fat is about 9,440 kilocalories a kilogram, lean tissue about 1,816, and the app's estimate of the fat share depends on BMI, with a discount for age without strength training and for short sleep. That estimate — the same one the app uses — is the least certain part of the calculation, and it is shown so you can see it.

Because the weight falls, the kilograms per week fall with it and the weeks to goal are more than the straight line from the first week would suggest. Both figures are shown. Real progress is usually slower still: the body's expenditure drops as weight drops (the energy model behind the "3,500 calories per pound" rule was replaced for exactly this reason), the first weeks' water loss flatters the rate, and nobody holds a deficit every single week. Treat the number as the lower bound of an honest estimate.

What it does not do

It does not check the daily target against the floors the app applies — a minimum energy per kilogram of lean mass, a sex-specific floor, and the energy needed to fit the minimum protein and fat. The app does, and reduces the pace when a floor binds. For that check you need the app's Energy Setup, or at least the daily energy calculator to see what the deficit is being taken from.

In the app

The app plans by the same share of trend weight, re-issues the daily target each week from the new weight, and caps the share at one percent. It also reduces the pace itself when the floors do not allow the deficit you asked for, and says so.

Sources

Hall KD, „What is the required energy deficit per unit weight loss?“, Int J Obes 2008;32:573–576 — mathematical model + published data
Limitation: модел върху Forbes; не индивидуална прогноза; не дава едно универсално число

cited, not reproduced
CDC, Steps for Losing Weight — official public-health guidance
Limitation: population advice, не медицински hard safety cap
Garthe I et al., „Effect of two different weight-loss rates on body composition and strength…“, Int J Sport Nutr Exerc Metab 2011;21(2):97–104 — randomized trial (n=24)
Limitation: елитни спортисти, 4 силови тренировки седмично, малка извадка; бързата група не губи чиста маса, просто не я увеличава; не е обща популация и не дефинира безопасен максимум

cited, not reproduced
Deurenberg et al., BMI/age/sex body-fat equation — original model study
Limitation: SEE около 4.1 percentage points body fat

cited, not reproduced

Educational information, not medical advice. It does not replace a consultation with a doctor or a registered dietitian. Not for people under 18, during pregnancy or breastfeeding, or with a history of an eating disorder — talk to a professional first.