Metabolism

From basal metabolic rate (BMR) to daily activity (NEAT): how total energy use is built — and how a hardgainer can steer it.

What does “metabolism” mean?

In shortMetabolism comprises all biochemical processes that provide, convert and store energy. For daily practice, the key is total daily energy expenditure (TDEE):

BMR/RMR: basal/resting metabolic rate for vital functions.
NEAT: non-exercise activity outside planned training.
EAT: energy from exercise/training.
TEF: thermic effect of food (~10% of intake).

TDEE = BMR/RMR + NEAT + EAT + TEF

BMR vs RMR: the difference

BMR (Basal Metabolic Rate): measured under strictly standardised conditions (clinical).
RMR (Resting Metabolic Rate): more practical; slightly higher than BMR.
Formulae: Mifflin–St Jeor, Katch–McArdle (with body fat) — solid starting estimates.

Understand BMR Learn about NEAT

Adaptive thermogenesis: a dynamic system

Down-regulation: prolonged deficit → hunger ↑, NEAT ↓, RMR slightly ↓.
Up-regulation: higher food intake/movement → NEAT ↑, heat production ↑.
Hardgainer factor: often naturally higher NEAT and “fidgeting” → higher needs.

Note: a “slow metabolism” is often confused with inconsistent calorie intake.

Practice for hardgainers: levers to pull

Calorie surplus: start with +500–700 kcal above needs; adjust after 14 days.
Protein: 1.6–2.2 g/kg/day, 3–4 meals (25–35 g per meal).
NEAT corridor: e.g., 7,000–9,000 steps/day while gaining.
Training: 3–4 sessions, moderate volume, steer effort with RPE and track RIR.
Volume & recovery: hit MEV, respect the SRA window; plan deloads.
Sleep/stress: 7.5–9 h; downshift after meals.

Common myths & clarifications

“I have an extremely slow metabolism.” Often it’s too little food, high NEAT, or lack of consistency.
“Six meals a day speed up metabolism.” The thermic effect depends on the amount, not frequency.
“More is more” in training. Excess volume stalls progress and recovery.

Myth #2: “More is more”? Myth #1: Six-meal dogma

Measuring & estimating

Indirect calorimetry: very precise, but rarely available.
Formulae + 14-day trend: estimate BMR → infer TDEE → average weight/calories/steps.
Adjust: weight flat? add +150–250 kcal. Rising too fast? subtract −100–150 kcal.

TDEE ≈ BMR + NEAT + EAT + TEF • TEF ≈ ~10% of intake