Basal metabolic rate and daily needs, plus the targets for losing fat or gaining mass. Five fields, no sign-up.
Your basal metabolic rate is what you burn doing nothing: breathing, staying warm, thinking. It is calculated with Mifflin-St Jeor, the formula with the lowest error across the general population. Enter a body fat percentage and we switch to Katch-McArdle, which starts from lean mass and is more accurate for people who have trained for a while.
Daily needs are that figure multiplied by how much you move (from 1.2 if you sit all day to 1.9 if you train twice a day). From there: −20% to lose fat, +10% to gain. These are starting points to correct after two weeks by watching the scale, not verdicts.
Estimates, for information only: they do not replace a doctor or a dietitian, and should not be used during pregnancy, while breastfeeding, or with a medical condition.
GiFit Pro makes the two-week correction on its own. A formula like Mifflin-St Jeor is a population average: on a real person it can be off by a few hundred kcal a day. Adaptive maintenance measures what you really burn, with two things the app already collects — what you eat (the diary) and how your weight moves (the weigh-ins) — counting 7,700 kcal per kilo. Eat 2,300 kcal a day for three weeks at a steady weight and your maintenance is about 2,300, whatever the formula says.
It starts once you have 14 days of food diary and at least 2 weigh-ins a week, in each of the last 2 weeks.
Best to weigh yourself every day, at the same time. Until then the formula stays, and the app tells you what is missing.
From there the number is refined every 2 days, by at most 100 kcal a step, up or down. Recent days count more — yesterday counts twice as much as two weeks ago, over a window of up to 28 days — and forgotten days do not count: empty, or under half your typical day with a single meal logged. A light day logged across several meals does count, because it was meant: the rest day of someone who eats more on training days, or a 5:2 fasting day. The result always stays between 0.8 and 2.5 times your basal metabolic rate.
A manual target, such as your dietitian's, always wins; the goal of losing or gaining applies on top. In the diary the number reads «Adaptive goal», so you know where it comes from. And with adaptive maintenance in use, calories burned training are not added to the budget: the scale has already measured them, and adding them would count them twice.
It is part of GiFit Pro, switched on by default (Settings → Goals and macros); in the free version the formula stays. Pro has a 14-day free trial on the monthly plan. If you kept your diary in FatSecret, bring it along: days from the last 4 weeks count toward the 14 it needs. Here is how.
GiFit starts from this number and, with Pro, corrects it on its own from your diary and your scale. You log what you eat with barcode scanning and your country's food catalogue. No account, and the diary never leaves your phone.