- BMR (Mifflin-St Jeor)1780 kcal
- Activity factor× 1.55
- Cut (−500 kcal)2259 kcal
- Bulk (+300 kcal)3059 kcal
TDEE-drift during a 12-week cut (illustrative)
A static BMR×activity number remains 2700 kcal. The actual energy output (rolling measurement from kcal intake and weight progression) gradually drops to ~2350 kcal — approximately 13% metabolic adaptation, well within the 5–15% range reported by Trexler et al. (2014).
Sources & methodology
The activity multipliers (1.2 to 1.9) are derived from Harris-Benedict-based tables that are widely used in fitness literature. Vytrix app periodically refines this estimate with sufficiently complete logs with logged intake and a smoothed weight trend — see the Adaptive TDEE paper.
- Mifflin, M. D. et al. (1990) — A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr (PMID 2305711)
- Trexler, E. T., Smith-Ryan, A. E., Norton, L. E. (2014) — Metabolic adaptation to weight loss: implications for the athlete. J Int Soc Sports Nutr
- Compendium of Physical Activities (2024 edition) — MET values per activity
- Vytrix Adaptive TDEE paper
Activity multipliers are an initial estimate; individual deviation may be ±15–20% depending on NEAT (non-exercise activity thermogenesis). Do you want this more precisely? Vytrix app measures your actual TDEE adaptively from kcal intake and weight change.