Why calorie targets need reviewing as your weight changes

Updated September 6, 2026.

A TDEE calculator gives a starting estimate from weight, height, age and activity. It helps with planning, but does not measure your individual metabolism. The original Mifflin–St Jeor study developed a resting-energy prediction equation in healthy adults; estimating activity introduces additional uncertainty.

Why maintenance calories can change

Body size, activity and adaptation can change energy needs during weight loss. Hall and colleagues’ model explains why a constant calorie change does not produce indefinite linear weight loss.

A plateau alone does not establish a slower metabolism. Water retention, changing food intake, logging gaps and activity changes can also contribute.

Adapt the estimate — don’t mistake it for a measurement

Food records and repeated weigh-ins can help refine an estimate. If body energy stores are stable and intake is accurately known over a representative period, average intake approximates expenditure. Two weeks of unchanged scale weight do not prove those conditions: water can mask tissue changes and a food diary can miss energy intake.

Makuro blends information from intake and weight with a formula baseline. It cannot separate systematic underlogging from lower expenditure. Our methodology explains how the two are weighted, the evidence behind each step, and the limits of the 7,700 kcal/kg approximation.

Make the records more useful

• Log drinks, oils and snacks as well as meals. Mark partially logged days incomplete.
• Mark a full zero-energy fasting day explicitly; a missing log is not a fast.
• Weigh under comparable conditions and look beyond individual readings.
• Review the pattern weekly. Do not make an aggressive calorie cut just because the scale pauses for a few days.

Adaptive tracking is a feedback tool, not a diagnosis or a guarantee of a chosen weight-loss rate. Clinical conditions and individual nutritional needs may require professional guidance.