How Many Calories Should You Eat Per Day? A No-Nonsense Guide to TDEE
How Many Calories Should You Eat Per Day? A No-Nonsense Guide to TDEE
June 8, 2026 · 8 min read · by the Calculator Gi team
Your calorie budget has four line items
Total Daily Energy Expenditure (TDEE) is the sum of: your basal metabolic rate (BMR — energy to stay alive at rest, 60–70% of the total), the thermic effect of food (digesting costs about 10% of intake), planned exercise, and NEAT — non-exercise activity like walking, posture and fidgeting, which varies between individuals by several hundred calories a day.
The standard estimation method, used by our calorie calculator, computes BMR with the Mifflin-St Jeor equation (the most accurate general-population formula in validation studies) and multiplies by an activity factor between 1.2 and 1.9.
Setting your target: deficit, surplus or maintenance
One kilogram of body fat stores roughly 7,700 kcal. A 500–550 kcal daily deficit therefore produces about half a kilogram of loss per week — fast enough to see progress, slow enough to preserve muscle and sanity. Aggressive deficits beyond 25% of TDEE accelerate muscle loss, tank energy, and have worse long-term adherence in studies.
For muscle gain, a modest surplus of 250–350 kcal with adequate protein (1.6–2.2 g per kg of body weight) and progressive resistance training adds muscle while limiting fat gain. Bigger surpluses mostly add fat — the muscle-building machinery has a speed limit.
Why the calculator is only your starting point
Every formula carries a ±10% error band, and food logging studies show people under-report intake by 20–40% on average — even dietitians under-report. So treat your calculated TDEE as a hypothesis, not a verdict.
The protocol that actually works: eat at your calculated target for two to three weeks, weigh yourself daily under consistent conditions, and compare the weekly average trend against expectation. Losing slower than planned? Reduce intake by 150–200 kcal. Faster, or feeling drained? Add some back. Your real TDEE is whatever number the scale trend reveals.
Metabolic adaptation and diet breaks
As you lose weight, TDEE falls — a smaller body burns less, NEAT quietly decreases, and hormonal adaptation adds a further small drag. A 10 kg loss can lower daily expenditure by 200–300 kcal, which is why a deficit that worked in month one stalls by month four. Recalculate after every 5 kg of change.
Periodic diet breaks — one to two weeks at maintenance every 8–12 weeks — improve adherence, restore training quality and partially reverse adaptation. Sustainable beats optimal: the best calorie target is one you can hit on your worst week, not your best.
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