A calorie deficit means you eat fewer calories than your body burns. It's the one requirement for losing fat — when food energy runs short, your body taps its fat stores. In practice: work out your daily expenditure (TDEE), then subtract about 15–20% (usually 300–500 kcal), giving a sustainable loss of ~0.25–0.75 kg (0.5–1.5 lb) per week. With enough protein (1.8–2.2 g/kg) and strength training you lose fat while keeping muscle. You don't need to starve — too large a deficit slows you down, burns muscle and is hard to sustain.
Find your deficitWork out how many calories you burn a day. The calculator uses BMR (Mifflin-St Jeor) × an activity factor = your TDEE, the starting point for everything.
Take roughly 300–500 kcal off your TDEE. That's a small-to-moderate deficit that yields ~0.25–0.75 kg a week without much hunger.
Aim for 1.8–2.2 g of protein per kg of body weight — protein preserves muscle in a deficit and is the most filling, so you stick with it.
Lifting 3–5× a week signals your body to keep muscle, so you lose fat instead of muscle. Walking and cardio burn extra calories on top.
Weigh in and measure your waist weekly. If there's no drop for 2–3 weeks, take off another ~100–200 kcal or add movement. Weight swings day to day — follow the trend, not one reading.
Start with the numbers: calorie & macro calculator · meal plan · body recomposition.
A bigger deficit isn't automatically better — pick it based on how much you value speed versus sustainability and keeping muscle.
About 150–350 kcal less. The slowest loss (~0.25 kg/week) but the easiest to sustain and best for keeping muscle — ideal if you're already lean.
About 400–500 kcal less. The sweet spot: ~0.5 kg a week, a good balance of speed and sustainability for most people.
Over ~600 kcal less. Faster drop (~0.75–1 kg/week) but a higher risk of muscle loss, hunger and low energy — short-term only, with plenty of protein.
A state where you take in fewer calories than your body burns. Your body then uses its fat stores for energy, so you lose weight.
For most people a small-to-moderate deficit of ~15–20% of TDEE (about 300–500 kcal), giving a sustainable ~0.25–0.75 kg per week.
Calculate your TDEE: your BMR from the Mifflin-St Jeor formula multiplied by an activity factor. Our calculator does it automatically from your measurements.
Yes — keep the deficit moderate, protein high (1.8–2.2 g/kg) and train with weights. Those signal your body to burn fat while keeping muscle.
As you lose weight your expenditure drops, shrinking the deficit. Recalculate TDEE at your new weight and, if needed, cut another ~100–200 kcal or add movement.
Faster yes, better no: an aggressive deficit eats muscle, tanks energy and mood, and is hard to keep up, so it often leads to rebound. Moderate is more sustainable.
MicroPlan turns your measurements into calories, a deficit and macros, builds a meal plan and tracks your progress — free, no account.
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