UNDERSTAND THE METHOD
How to use this calculator
Enter an adult profile, goal weight, physical activity level, and dates. This model keeps physical activity fixed and assumes carbohydrate supplies half of daily energy. It solves for the intake that reaches the chosen weight in the model.
What the result can tell you
The model is for adult scenarios, not pregnancy or breastfeeding. It is not a personal intake prescription or an exact reproduction of the NIH Body Weight Planner. Food composition, sodium, adherence, and individual physiology can change a real trajectory. Dates are model estimates.
Common questions
What does the body-weight planner solve?
Enter an adult profile, goal weight, activity level, and dates. The model keeps activity fixed, assumes carbohydrate supplies half of daily energy, and solves for the intake that reaches the selected weight in the model.
Is the result a personal calorie prescription?
No. It is an adult scenario model and is not an exact reproduction of the NIH Body Weight Planner. Food composition, sodium, adherence, and individual physiology can change a real trajectory.
Sources & limitations
Sources checked September 12, 2026. These notes identify methods and assumptions. They have not received an independent clinical review.
- Hall and colleagues describe a dynamic energy-balance model.pmc.ncbi.nlm.nih.gov
- The model appendix provides state equations and constants.niddk.nih.gov
- Body-fat estimation used to initialize the model.pubmed.ncbi.nlm.nih.gov