Crash diets work — until they reverse spectacularly. Sustainable weight loss has a speed limit, and the math is unforgiving.
This used to be a back-of-the-envelope job. Now it is one tap, but the logic has not changed. Crash diets work — until they reverse spectacularly. Sustainable weight loss has a speed limit, and the math is unforgiving.
1 kg of body fat ≈ 7,700 kcal. 500 kcal deficit/day → ~0.45 kg/week. 1,000 kcal deficit → ~0.9 kg/week.
Beyond 1% bodyweight loss per week, you start losing significant muscle. Muscle loss lowers TDEE, slowing future loss.
Week 4–8: water weight normalises, metabolism adapts. Plateau is normal. Stay the course, don't slash calories further.
Every 8–12 weeks of deficit, eat at maintenance for 1–2 weeks. Restores hormones, rebuilds adherence.
Why am I gaining weight in week 1 of a workout plan? Glycogen stores plus water. Real fat trend takes 3–4 weeks to read.
Is intermittent fasting magic? No — it just makes calorie deficits easier for some people. Same math underneath.
Run your own numbers before you trust a rule of thumb. Two minutes saves a lot of regret.