Trajectory

Burn is fitted by weighted least squares on the energy-balance identity across the window, not by differencing its two endpoints, so a single water-weight day nudges the answer instead of swinging it. The fit is blended against the Mifflin-St Jeor estimate by confidence, which rises with window span, weigh-in count and intake coverage. Inside the projection, burn is recalculated from the simulated weight every day, so it falls as you lose and the curve flattens. Energy converts at 7,700 kcal per kg, which assumes fat: early loss is largely water, so the fitted burn reads high in the first weeks and settles as data accumulates. The fit also inherits any bias in your food logging, since it cannot distinguish under-reported intake from a slower metabolism.