To lose fat you need a calorie deficit: eating less energy than you burn, so your body makes up the difference from stored fat. A good size for most people who lift is a deficit that produces 0.5–1 % of bodyweight loss per week, typically 300–700 kcal below maintenance. Find your maintenance first, subtract, then let your weekly average weight tell you whether to adjust. Stalls are normal and usually have boring explanations.
What a calorie deficit actually is
Your body burns energy all day: to keep you alive (basal metabolism), to digest food, to move around (from fidgeting to walking), and to exercise. Together that’s your maintenance calories, also called TDEE (total daily energy expenditure). Eat below it and you’re in a deficit; eat above it and you’re in a surplus.
The diet that creates the deficit matters less than people argue about. The ISSN position stand on diets and body composition (Aragon et al., 2017) concludes that low-carb, low-fat and other approaches produce similar fat loss when calories and protein are matched. Pick the style you can stick to.
Step 1: estimate your maintenance calories
Start with a quick estimate, then refine it with real data.
Rough estimate (kcal per kg of bodyweight per day):
| Daily activity | kcal per kg | 70 kg person | 90 kg person |
|---|---|---|---|
| Desk job, little walking, lifting 3×/week | 28–31 | ~2,000–2,150 | ~2,500–2,800 |
| Moderately active, 7–10k steps, lifting 3–4×/week | 31–35 | ~2,150–2,450 | ~2,800–3,150 |
| Very active job or lots of sport | 35–40 | ~2,450–2,800 | ~3,150–3,600 |
Refine it: eat your usual diet, log it as honestly as you can for 14 days, and weigh yourself every morning. If your weekly average weight is flat, your average intake is your maintenance. If it’s rising or falling, adjust: roughly 0.5 kg per week corresponds to about 500 kcal a day.
Step 2: choose the size of your deficit
Bigger deficits lose weight faster, but more of it comes from muscle and they’re harder to sustain. Garthe and colleagues (2011) showed this in athletes who lifted while dieting: losing 0.7 % of bodyweight per week preserved muscle and improved strength better than losing 1.4 %.
| Deficit | Expected weekly loss (early on) | Good for |
|---|---|---|
| 10–15 % below maintenance (~250–400 kcal) | ~0.25–0.4 kg | Lean lifters, recomposition, minimal hunger |
| 20 % (~400–600 kcal) | ~0.4–0.6 kg | Most people |
| 25 % or more (~600–900 kcal) | ~0.6–0.9 kg | Higher body fat, short periods |
A 70 kg person at 2,300 kcal maintenance might eat about 1,850 kcal for a moderate deficit. For the training side of a diet, see how to cut without losing muscle.
Step 3: make the deficit easy to live with
The best deficit is one you barely notice. A few habits do most of the work:
- Protein at every meal. It’s the most filling macronutrient and protects muscle. Aim for 1.8–2.4 g per kg in a deficit; see how much protein to build muscle and our list of high-protein foods.
- High-volume foods. Vegetables, fruit, potatoes, soups and lean protein give a lot of food for few calories.
- Cut liquid calories first. Juice, sugary coffee drinks, soda and alcohol add calories that don’t fill you up.
- Watch the sneaky ones. Cooking oil (a tablespoon is about 120 kcal), sauces, nuts and “just a bite” of things add up fast.
- Walk more. An extra 3,000–4,000 steps a day burns roughly 150–250 kcal with almost no fatigue. More in cardio and weight training.
Why the scale stalls in a deficit
Almost everyone hits weeks where the scale doesn’t move. Before you slash calories, check these.
1. Water is hiding fat loss
Salt, carbs, stress, poor sleep, a hard leg session and the menstrual cycle all make you hold water, often 1–2 kg. A week of “no progress” followed by a sudden whoosh down is extremely common. That’s why you use weekly averages and judge over two to three weeks, not days.
2. You’re eating more than you think
Most people underestimate their intake, often by a lot. Common gaps: weekends, cooking oils, drinks, condiments, tastes while cooking and portion creep. Weigh food for a week to recalibrate.
3. Your maintenance has dropped
As you lose weight, you burn less: a smaller body costs less to run and to move. Many people also move less without noticing when dieting (fewer steps, less fidgeting). Research by Hall and colleagues (2011) showed why the old “3,500 kcal per pound” rule overestimates long-term weight loss: as you get lighter, the same intake produces a smaller and smaller deficit. Recalculate every 4–6 weeks.
4. You’re building muscle
Beginners and returning lifters can gain some muscle while losing fat (recomposition). The scale moves slowly, but your waist shrinks and your lifts go up.
| What you see for 2–3 weeks | Likely reason | What to do |
|---|---|---|
| Weight flat, waist shrinking, lifts up | Recomposition or water | Keep going |
| Weight flat, waist flat | Intake crept up or maintenance dropped | Track accurately; then remove 150–200 kcal or add steps |
| Weight dropping fast, lifts dropping | Deficit too big | Add 150–200 kcal |
| Weight up after a salty meal or hard week | Water | Ignore, check again next week |
Keep your training heavy during a deficit
Lifting during a deficit is what makes the weight you lose fat rather than muscle. Keep the loads on your main lifts roughly where they were, trim a set or two if recovery suffers, and follow a structured plan like our cutting workout plan.
Your lifts are also an early warning system. If your strength holds while the scale drops, the deficit is fine. If your key lifts slide for two or three weeks in a row, it’s probably too steep. Brick shows last time’s numbers on every set and an estimated 1RM trend for each exercise, so you’ll see that slide clearly instead of guessing.
How long to stay in a deficit
Most diets go best in blocks of 8–16 weeks, followed by at least a few weeks at maintenance. Long, unbroken deficits make hunger, fatigue and poor sleep more likely. Planned breaks of one to two weeks at maintenance don’t undo your progress and make the next block easier.
Quick checklist
- Track two weeks to find true maintenance.
- Subtract 15–25 % (more only if you have a lot to lose).
- Protein high, liquid calories low, steps up.
- Weigh daily, judge weekly averages over 2–3 weeks.
- Adjust by 150–200 kcal at a time.
- Keep lifting heavy.
Frequently asked questions
Is a 500 calorie deficit good?
For many people it's a sensible default: it typically produces around 0.4–0.5 kg (about 1 lb) of loss per week at first. If you're small or already lean, 500 kcal may be too aggressive; aim for 0.5–1 % of bodyweight per week instead of a fixed number.
Why am I in a calorie deficit but not losing weight?
Usually one of three things: you're eating more than you think (weekend meals, oils, drinks), water retention is hiding fat loss, or your maintenance has dropped as you got lighter. Give it two to three weeks of accurate tracking before changing anything.
Can I lose fat without counting calories?
Yes. Counting is a tool, not a requirement. Eating mostly whole foods, prioritising protein and vegetables, reducing liquid calories and walking more all create a deficit without numbers. Counting helps when progress stalls or you want precision.
How low should my calories go?
As high as possible while still losing at a steady rate. Very low intakes make it hard to get enough protein, fibre and micronutrients and are rarely sustainable. Diets far below roughly 1,200 kcal for women or 1,500 kcal for men should only be done with medical supervision.
Sources
- Hall KD, Sacks G, Chandramohan D, Chow CC, Wang YC, Gortmaker SL, Swinburn BA (2011). Quantification of the effect of energy imbalance on bodyweight. The Lancet
- Aragon AA, Schoenfeld BJ, Wildman R, et al., Antonio J (2017). International Society of Sports Nutrition position stand: diets and body composition. Journal of the International Society of Sports Nutrition
- Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J (2011). Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. International Journal of Sport Nutrition and Exercise Metabolism
