FAQ

Common questions about BMR, TDEE, and macros.

Q1. Which formula is better — Mifflin or Katch?

Katch-McArdle uses lean body mass and is more accurate when body-fat % is known. Without it, Mifflin-St Jeor is the current gold standard for the general population.

Q2. How accurate is TDEE really?

These formulas have ±10% accuracy for most. Track your weight weekly and adjust calories up/down by ~200 kcal every 2 weeks if results differ from target.

Q3. Why is my protein so high (2.2 g/kg)?

During calorie deficits, higher protein preserves muscle mass and keeps satiety high. The recommendation drops to 1.6 g/kg at maintenance.

Q4. What if I have very little body fat?

Provide your body-fat % so Katch-McArdle is used. Very lean individuals often have higher BMR than Mifflin predicts because of their metabolically active muscle tissue.

Q5. Is 1,200 kcal the absolute minimum?

Most professional guidelines suggest not dropping below 1,200 kcal for women and 1,500 kcal for men without medical supervision. This tool caps the "cut" mode at 1,200 kcal.

Q6. Can I use this while pregnant or breastfeeding?

No. Pregnancy and lactation have specific caloric needs (+300–500 kcal). Consult a healthcare professional.

Q7. Does this account for thyroid conditions or metabolic disorders?

No. TDEE formulas assume a healthy metabolism. If you have a diagnosed condition, your BMR may be significantly different, and you should work with a medical professional.

Q8. Why is "activity level" so subjective?

Multipliers are broad averages. Many underestimate sedentary jobs and overestimate "moderate". When in doubt, pick the lower level and adjust if weight trends diverge.

Q9. Should I eat back my exercise calories?

If you set Activity Level correctly to include exercise, do not add calories back (it would double-count). If you set "Sedentary" despite exercising, you should add back ~60% of estimated burn.

Q10. How often should I recalculate?

Every 5 kg of weight change or every 8 weeks of training to keep the TDEE realistic. Hormones, NEAT, and adaptation shift over time.