If you've typed "how many calories should I eat to lose weight" into Google, you're not alone — it's one of the most searched health questions in the UK. The honest answer is: it depends on your sex, weight, height, age and how active you are. But there's a simple framework that works for most people, and the NHS is very clear about what's safe.
This guide gives you the numbers, the maths behind them, and a free calculator to work out your personal target.
The short answer
The NHS recommends most adults reduce their daily calorie intake by around 600 kcal below maintenance to lose weight at a safe, sustainable rate of roughly 1lb (0.5kg) per week.
- Average woman: ~2,000 kcal/day
- Average man: ~2,500 kcal/day
For weight loss, that drops to roughly 1,400 kcal for women and 1,900 kcal for men — but these are just averages. Your real number depends on your body and activity level.
How calorie deficit actually works
Weight loss comes down to one rule: eat less energy than you burn. Your body makes up the difference by using stored fat.
The maths is straightforward:
- 1 lb of body fat = roughly 3,500 calories
- Daily deficit of 500 kcal = ~1 lb lost per week
- Daily deficit of 1,000 kcal = ~2 lb lost per week (the safe upper limit)
Going below a 1,000 kcal/day deficit isn't more effective — it usually backfires. You lose muscle, your metabolism adapts downwards, and the weight comes back the moment you stop. Slow and steady wins this one.
Working out your calorie target
To get a personal number, you need two things: your BMR (Basal Metabolic Rate — calories burned at rest) and your activity level. Multiply them together and you get your TDEE — Total Daily Energy Expenditure. That's your maintenance calories. Subtract 500–600 from that and you've got your weight-loss target.
Step 1: Find your BMR
The Mifflin–St Jeor equation is the gold standard:
- Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Step 2: Multiply by your activity level
| Activity level | Multiplier |
|---|---|
| Sedentary (desk job, little exercise) | × 1.2 |
| Lightly active (1–3 workouts/week) | × 1.375 |
| Moderately active (3–5 workouts/week) | × 1.55 |
| Very active (6–7 workouts/week) | × 1.725 |
Step 3: Subtract 500–600 calories
That's your daily target for losing roughly 1 lb per week. Or just use our free calculator below — it does the maths for you.
Sample daily calories for UK adults
For a 5'5" (165cm), 30-year-old woman weighing 11 stone (70kg) at a sedentary activity level, maintenance is roughly 1,800 kcal. Weight-loss target: ~1,300 kcal/day.
For a 5'10" (178cm), 35-year-old man weighing 14 stone (89kg) at a moderately active level, maintenance is roughly 2,800 kcal. Weight-loss target: ~2,200 kcal/day.
Don't go too low
The NHS and most UK weight-loss services warn against eating below 1,200 kcal/day for women or 1,500 kcal/day for men without medical supervision. Below that, you can't reliably get all the nutrients your body needs, and it's almost impossible to sustain.
What about exercise?
Exercise gives you more calories to play with, but you can't out-train a bad diet. Most weight-loss specialists agree that the deficit is created in the kitchen, not the gym. That said, the NHS recommends 150 minutes of moderate activity per week for general health — and resistance training helps preserve muscle while you're in a deficit.
Common pitfalls
- Underestimating intake. UK research has shown most people underestimate what they eat by 20–30%. Weighing food for the first week is humbling but useful.
- Liquid calories. A latte, a glass of wine and a smoothie can easily add 600 kcal — your entire deficit, gone.
- Weekend resets. Eating cleanly Mon–Fri then over by 2,000 kcal at the weekend wipes out the deficit.
- Plateauing without adjusting. As you lose weight, your TDEE drops. Recalculate every stone or so.
The bottom line
For most UK adults, losing weight means eating roughly 500–600 kcal below your daily maintenance — typically 1,400–1,500 kcal for women and 1,900–2,000 kcal for men. Use the calculator to get your exact number, then track honestly for two weeks before judging whether it's working.
Sources: NHS Better Health / Live Well, British Nutrition Foundation, Mifflin–St Jeor (1990). This article is for general information only and does not replace medical advice. Speak to your GP before starting a weight-loss plan if you have any health conditions.