How Alcohol Adds Calories and Reduces Fat Oxidation Within Your Daily TDEE — 2026

Basal Metabolic Rate (BMR) is the calories your body burns at complete rest to keep you alive — breathing, circulation, and cell repair. Total Daily Energy Expenditure (TDEE) adds the energy of daily activity, digestion, and exercise. BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + s, where s is +5 for men and −161 for women. This Mifflin–St Jeor equation is the most validated modern formula.

Multiply BMR by an activity factor to estimate TDEE. A moderate deficit below TDEE (about 10–20%, or roughly 300–500 kcal/day for many adults) supports gradual fat loss while preserving muscle; a small surplus supports muscle gain.

• Sedentary (little or no exercise): BMR × 1.2
• Lightly active (1–3 days/week): BMR × 1.375
• Moderately active (3–5 days/week): BMR × 1.55
• Very active (6–7 days/week): BMR × 1.725
• Extra active (physical job + training): BMR × 1.9

Water, temperature, and altitude have small, short-term effects on energy use but do not change your underlying BMR materially. They matter more for how you feel and perform during activity. The U.S. National Academies of Sciences, Engineering, and Medicine estimate total daily water intake (from beverages and food) of about 3.7 liters (≈15.5 cups) for men and 2.7 liters (≈11.5 cups) for women. Needs rise with exercise, heat, and illness.

BMR falls with age and with weight loss, so revisit your numbers every few months or after significant changes in weight, training, or life stage. Treat TDEE as an estimate to adjust against real-world results over weeks.