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Metabolism tool

Body Composition & Metabolic Estimator

Mifflin-St Jeor BMR and TDEE with overlaid projected fat-loss curves for low, mid and high research-stage doses of GLP-1 class peptides.

Subject parameters

yrs
cm
kg

Approximations from published GLP-1 / dual-agonist trial literature.

weeks

BMR

1843 kcal/d

TDEE

2856 kcal/d

Est. weekly Δ

-0.47 kg/wk

Projected cumulative reduction

-1.4kg-2.8kg-4.2kg-5.6kgwk 3wk 6wk 9wk 12

Projections assume a 7,700 kcal-per-kilogram body-fat equivalency and a stable energy intake. Real-world research subjects typically plateau at 65 – 80% of the projected curve due to metabolic adaptation.

The Mifflin-St Jeor equation

BMR is calculated using the Mifflin-St Jeor equation, the most accurate predictor of resting energy expenditure in published validation studies. TDEE is BMR multiplied by an activity factor between 1.2 (sedentary) and 1.9 (very active). Projected fat-loss curves assume a 7,700 kcal-per-kilogram body-fat equivalency and a sustained energy deficit proportional to the published-trial deficit for the selected research dose intensity.

Caveats

  • Real-world research subjects plateau at 65 – 80% of the projected curve due to metabolic adaptation.
  • Body recomposition (concurrent lean-mass changes) is not modelled.
  • Trial data are derived from published GLP-1 and dual-agonist literature; individual responses vary widely.

Supporting research

  • Mifflin MD et al., A new predictive equation for resting energy expenditure, Am J Clin Nutr, 1990.
  • Wilding JPH et al., Once-Weekly Semaglutide in Adults with Overweight or Obesity, NEJM, 2021.
  • Jastreboff AM et al., Tirzepatide Once Weekly for the Treatment of Obesity, NEJM, 2022.

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Frequently asked questions

What is the Mifflin-St Jeor equation?
Mifflin-St Jeor is the most accurate published predictor of resting energy expenditure (BMR). For males: BMR = 10·weight(kg) + 6.25·height(cm) − 5·age + 5; for females, subtract 161 instead of adding 5.
How is TDEE different from BMR?
BMR is resting energy expenditure — the calories needed just to maintain basic physiology. TDEE is BMR multiplied by an activity factor (1.2 sedentary to 1.9 very active) to estimate total daily expenditure including movement and thermic effect of food.
How accurate are the GLP-1 fat-loss projections?
Projections assume a sustained percentage energy deficit drawn from published GLP-1 and dual-agonist trial data and a 7,700 kcal-per-kilogram body-fat equivalency. Real-world research subjects plateau at 65–80% of the curve due to metabolic adaptation — the model is a useful ceiling, not a forecast.
Does the estimator account for lean-mass changes?
No — the projection models fat-mass change only. GLP-1 trials typically report 75–85% of weight loss coming from fat mass and 15–25% from lean mass; investigators concerned about lean preservation usually add a resistance-training arm.
Can I use the estimator for non-GLP-1 peptides?
For non-incretin peptides like AOD-9604 or Tesamorelin, set the protocol intensity to "baseline" and use the BMR/TDEE values as a planning input only. Phase 2 of the site roadmap will add per-peptide projections for those classes.