Excaloricate
Everyone wants the fastest possible answer to "how long will this take," so they pick the biggest deficit they can stand and brace for the number to drop. It usually does — for about three weeks. Then it stalls, or the wheels come off entirely. The speed that feels efficient on day one is often the reason nothing sticks by day thirty.
Here's how to pick a rate you can actually live at.
The rule of thumb: 0.5–1% of bodyweight per week
Most of the sustainable-loss research lands in the same place: aim to lose about 0.5% to 1% of your bodyweight per week.
- 60 kg (132 lb): roughly 0.3–0.6 kg a week
- 80 kg (176 lb): roughly 0.4–0.8 kg a week
- 100 kg (220 lb): roughly 0.5–1 kg a week
The heavier you are, the faster you can safely go — a bigger body has more fat to draw energy from, so an aggressive-looking number is a gentler percentage. As you get leaner, the same weekly loss becomes a larger share of you, and you should ease off.
Why faster isn't better
A crash deficit doesn't just risk being unpleasant. It works against you in specific ways:
- You lose more muscle. The bigger the gap between what you eat and what you burn, the more of the loss comes from lean tissue rather than fat — especially without enough protein or any resistance training.
- Hunger scales with the deficit. A 300-calorie shortfall is a background hum. A 1,000-calorie one is a siren. The larger the gap, the harder your appetite pushes back, and the sooner most people break.
- It's a bad trade against adherence. A 25% deficit you hold for two weeks loses to a 15% deficit you hold for four months. The one you can keep always wins, and speed is usually what makes a plan un-keepable.
Translate the percentage into calories
A rough, useful conversion: about 7,700 calories per kilogram of fat (3,500 per pound).
To lose 0.5 kg a week, that's a ~550-calorie daily deficit. To lose 1 kg a week, ~1,100 a day — doable for a larger person, brutal for a smaller one. Set your daily target off the rate that matches your size, not the fastest number you can white-knuckle.
Read the trend, not the day
Bodyweight swings 1–2 kg day to day on water, sodium, and what's still in your gut — none of it fat. If you weigh daily, judge the weekly average against last week's, not this morning against yesterday. A rate that looks right over three weeks is real; a single scary reading is noise.
When to actually go faster
There are cases for a steeper deficit — a doctor-supervised plan, a clear medical reason, a lot of weight to lose and a body that tolerates it. But "I want it gone by summer" isn't one of them, because summer arrives and the weight comes back with interest. If you're choosing your own rate, the honest question isn't "how fast can I lose it" — it's "how slowly am I willing to, so it stays gone."