Glossary
Why 7,700 kcal per kilogram?
The conversion rate between a calorie balance and the scale. Eat 7,700 kcal less than you burn — over any stretch of time — and the rule says you lose about one kilogram.
Where the number comes from.
It is the metric cousin of the famous 3,500 kcal-per-pound rule, popularized by Max Wishnofsky in 1958. Body fat is not pure fat — adipose tissue is roughly 87% lipid plus water and cellular machinery — which lands its energy content near 7,700 kcal per kilogram rather than the ~9,300 of pure fat.
pace = daily balance × 7 ÷ 7,700 kg/week
What it gets right, and where it drifts.
As a planning tool over weeks, the rule is serviceable: it turns “430 kcal a day under” into “about 0.4 kg a week”, which is the number a goal date is made of. As a promise over months, it drifts — three things bend the line:
Water
Glycogen binds water, so the first weeks of a deficit lose “extra” weight that isn’t fat — and a salty or high-carb day can mask a real deficit for days.
Adaptation
During long deficits the body burns somewhat less than formulas predict, so the same intake slowly produces a smaller deficit.
Composition
Not all loss is fat. The leaner you get and the faster you go, the more lean mass is in the mix — and lean tissue holds far less energy per kilogram.
How Caaals keeps the estimate honest.
The projection uses 7,700 for the arithmetic, but it never trusts it blindly: the pace is recomputed from your last 14 days on every update, the chart anchors on your 7-day weigh-in trend rather than single weigh-ins, the projected curve is capped at 1.5 kg per week, and when the honest answer is “no date” — not enough data, barely moving — that is what it says.
Questions
Is the 3,500-calorie rule wrong?
It is a linearization — accurate enough over weeks, increasingly optimistic over months as the body adapts and the composition of loss shifts. Caaals limits the damage by recomputing the pace from your last 14 days on every update, rather than projecting one number to the horizon.
Why doesn't my weight loss match the formula?
The usual suspects: water swings (glycogen binds water, so early loss looks fast), metabolic adaptation during long deficits, lean-mass changes, and logging error. This is why the projection anchors on your 7-day weigh-in trend — the scale's trend is the measurement; the formula is only the plan.
Related: what is TDEE and how the projection works.
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