Question 1

What is basal metabolic rate (BMR)?

Accepted Answer

BMR is the number of calories your body burns at complete rest to keep you alive — powering breathing, circulation, temperature regulation, and organ function. It accounts for 60–75% of your total daily calorie expenditure and is the foundation for calculating your TDEE.

Question 2

What is TDEE and how is it calculated?

Accepted Answer

TDEE (Total Daily Energy Expenditure) is your total calorie burn per day, including all activities. It is calculated as TDEE = BMR × activity multiplier (1.2 for sedentary up to 1.9 for very active). Eating at your TDEE maintains your current weight.

Question 3

How many calories should I eat to lose weight?

Accepted Answer

A safe and sustainable calorie deficit for weight loss is 500 kcal/day below your TDEE, which creates approximately 0.5 kg (1 lb) of weight loss per week. Avoid going below 1,200 kcal/day for women or 1,500 kcal/day for men, as very low-calorie diets can cause muscle loss and metabolic adaptation.

Question 4

How many calories do I need to build muscle?

Accepted Answer

For lean muscle gain (clean bulk), aim for a caloric surplus of 250–500 kcal above your TDEE. This produces approximately 0.25–0.5 kg of weight gain per week. Ensure adequate protein intake (1.6–2.2 g per kg of body weight) to maximize muscle protein synthesis.

Question 5

What is the Mifflin-St Jeor equation?

Accepted Answer

Developed in 1990, the Mifflin-St Jeor equation is the most accurate standard BMR formula currently used by dietitians and nutritionists. For males: 10×weight(kg) + 6.25×height(cm) - 5×age + 5. For females: 10×weight(kg) + 6.25×height(cm) - 5×age - 161. It consistently outperforms the older Harris-Benedict equation.

Question 6

How do I choose the right activity level?

Accepted Answer

Sedentary (1.2): desk job, no exercise / Light (1.375): 1–3 days of light exercise/week / Moderate (1.55): 3–5 days of moderate exercise/week / Active (1.725): 6–7 days of hard exercise/week / Very Active (1.9): physical labor + training or twice-daily training. Most office workers fall into sedentary or light categories.

Question 7

Why does TDEE differ between men and women at the same weight?

Accepted Answer

Men generally have greater muscle mass and lower body fat percentage than women at the same weight. Since muscle tissue burns more calories than fat at rest, men typically have a higher BMR. The Mifflin-St Jeor equation accounts for this with a sex-specific constant (+5 for males, -161 for females).

Question 8

How accurate is a TDEE calculator?

Accepted Answer

TDEE calculators provide population-average estimates. Individual results may vary by ±20% or more due to genetics, thyroid function, gut microbiome, and other factors. Track your calorie intake and weight for 2–4 weeks and adjust your target based on actual weight change to calibrate your personal TDEE.

Question 9

Why does BMR decrease with age?

Accepted Answer

Aging causes a gradual decline in lean muscle mass (sarcopenia) and an increase in body fat. Since muscle burns more energy than fat at rest, losing muscle mass reduces BMR. BMR is estimated to decline approximately 2–5% per decade after age 30. Regular resistance training can slow this decline by preserving muscle mass.

Question 10

What are macros and how should I set them?

Accepted Answer

Macros are the three macronutrients: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). A balanced starting point is 30% protein, 40% carbs, 30% fat. For weight loss, increase protein to 35–40% to preserve muscle. For muscle gain, keep carbs higher (45–50%) to fuel workouts.

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