Time-restricted eating and standard calorie counting are often framed as competing weight-loss strategies. In practice, both depend on the same number: your total daily energy expenditure. If your TDEE target is wrong, the eating window you choose matters less than the daily error in your calorie budget.
Why TDEE is the anchor for any calorie plan
TDEE estimates the calories you burn in 24 hours, including basal metabolic rate, movement, and digestion. Basal metabolic rate typically accounts for 60–70% of that burn, physical activity for 20–30%, and the thermic effect of food for about 10%. Most adult women fall between 1,600 and 2,400 calories a day, and most men between 2,000 and 3,200 calories a day. Protein has the highest thermic effect—about 25% of its calories—while carbohydrate is around 7% and fat only 2–3%, so a high-protein diet quietly raises TDEE. When you eat below your TDEE you lose weight, at your TDEE you maintain, and above it you gain. That simple arithmetic is why a small misjudgment in TDEE can erase the planned effect of a time-restricted eating schedule.
How the calculator estimates your burn
Most calculators follow two steps. First estimate basal metabolic rate with the Mifflin–St Jeor equation: for men, 10 × weight in kg + 6.25 × height in cm − 5 × age + 5; for women, the same calculation ends with − 161. Then multiply that value by an activity factor. The common multipliers are ×1.2 for sedentary, ×1.375 for lightly active, ×1.55 for moderately active, ×1.725 for very active, and ×1.9 for extra active. A desk job plus four hard training days per week usually corresponds to ×1.55, not ×1.725. This multiplier is the largest source of variability in a TDEE estimate.
Where TDEE calculations go wrong
The most common error is choosing an activity multiplier that describes your best week rather than a typical week. Two people of the same size can differ in non-exercise activity thermogenesis by up to 400 calories a day just through fidgeting, posture, and daily movement. After a 10 kg weight loss, TDEE can fall by about 150–200 calories a day, so yesterday’s deficit can become today’s maintenance if you do not recalculate. For leaner individuals, formulas that use lean body mass, such as the Katch-McArdle formula, can be more accurate than Mifflin–St Jeor because they account for the metabolic difference between muscle and fat.
Time-restricted eating vs calorie counting
Time-restricted eating does not change the arithmetic; it changes when you eat. If an eating window helps you stop mindless snacking and stay below your TDEE, it supports weight loss. If it simply compresses the same overeating into fewer hours, it does not. Any comparison of the two approaches therefore depends on giving each participant a credible TDEE target and measuring how well they follow it. For a low-effort distraction during a fasting window, the Swedish-language Taipei Spel lets you play Taipei Mahjong Solitaire directly in the browser, keeping your hands busy without reaching for a snack.
Setting a safe deficit without stalling
Subtract about 500 calories a day from an honest TDEE for roughly 0.5 kg of weekly weight loss, or up to 750 calories a day for an aggressive short-term phase. Most women should not eat below 1,200 calories a day without medical supervision. Eat at the calculated target for two to three weeks, track your weight, and adjust by about ±100 calories a day if the scale does not match your expected maintenance. This closing of the loop is what turns a one-time estimate into a useful calorie target.
Practical conclusion
Start with the Mifflin–St Jeor equation, choose the activity multiplier that matches an ordinary week, and verify the result against the scale. Whether you use time-restricted eating or standard calorie counting, the first step is the same: know your TDEE well enough that your deficit is real but not extreme.