UNDERSTAND THE METHOD
How to use this calculator
Enter an adult profile and, if available, a measured body-fat estimate. The calculation compares estimated energy needs with a theoretical transfer coefficient of 48.51 kcal per kilogram of fat per day (about 22 kcal/lb).
What the result can tell you
This is a theoretical calculation. It cannot guarantee fat-only loss or muscle preservation. The 1,500/1,200 kcal display floors are product limits, not evidence of a safe personal intake. The model is not for pregnancy or breastfeeding.
Common questions
What does the fat-store transfer coefficient represent?
The scenario compares estimated energy needs with a theoretical transfer coefficient of 48.51 kcal per kg of fat per day, or about 22 kcal per lb.
Does this result guarantee fat-only loss or muscle preservation?
No. It is a theoretical model. The displayed calorie floors are product limits, not evidence of a safe personal intake, and the model is not for pregnancy or breastfeeding.
Sources & limitations
Sources checked September 12, 2026. These notes identify methods and assumptions. They have not received an independent clinical review.
- Alpert model of energy transfer from fat stores.pubmed.ncbi.nlm.nih.gov
- Hall discusses energy balance and body composition.pmc.ncbi.nlm.nih.gov