Use calculated calories as a starting hypothesis, not a fixed truth.
Daily energy needs are influenced by resting metabolism, movement, exercise, digestion, body composition and adaptation over time. A calculator cannot measure all of those factors directly, so the result should be tested against real observations.
Mifflin–St Jeor equation
The default method estimates resting energy from weight, height, age and a sex-specific equation constant.
Male constant: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
Female constant: BMR = 10 × kg + 6.25 × cm − 5 × age − 161
Female constant: BMR = 10 × kg + 6.25 × cm − 5 × age − 161
Body-fat-based mode
When a body-fat estimate is supplied, the optional body-fat-based mode uses estimated lean mass. Body-fat measurements themselves can have substantial error, so this does not automatically make the result more accurate.
What maintenance calories mean
Maintenance calories are the estimated intake at which body weight may remain broadly stable at the selected activity level. Actual needs should be checked using several weeks of consistent intake and body-weight trends.
Why weight change is not perfectly linear
The body adapts as weight, activity and intake change. Water, glycogen, sodium, digestion and menstrual cycles can also produce short-term scale changes that are not body-fat changes.
Macro targets
Macro percentages divide goal calories among protein, carbohydrate and fat. They are planning values rather than medical requirements. Food quality, fibre, vitamins, minerals and individual tolerance still matter.
How to improve the estimate
- Use consistent morning body-weight measurements when appropriate.
- Compare weekly averages rather than single-day changes.
- Keep activity and intake reasonably consistent during evaluation.
- Adjust gradually if the trend differs from the goal.
- Use professional guidance when medical or nutritional risk is present.