There is one question that, if you answer correctly, solves 80% of weight loss: how many calories do you burn per day and how many do you eat? Everything else — keto, intermittent fasting, Mediterranean — are just different methods of reaching the same place. All diets that work share one thing in common, even if they hide it under fancy names: they make you, in one way or another, consume fewer calories than you burn.

In this article we calculate together, with concrete numbers, how many calories you need to lose weight — and, equally important, why dropping too low is a mistake that comes back to bite you.

The basic rule, without detours

You lose weight when you consume fewer calories than you burn. This is called a calorie deficit and is the common mechanism behind all diets. There is no food that “burns fat,” there is no magic hour after which calories “no longer count,” and there is no combination of foods that makes you lose weight while in a caloric surplus. It’s less romantic than the ads promise, but it has one enormous advantage: it’s predictable and works every time.

Step 1: calculate your basal metabolic rate

Basal metabolic rate (BMR) is the calories you burn at complete rest — just to keep your heart, brain, and breathing running. A simplified formula, easy to use with a phone calculator:

• Women: 655 + (9.6 × weight kg) + (1.8 × height cm) − (4.7 × age)
• Men: 66 + (13.7 × weight kg) + (5 × height cm) − (6.8 × age)

For example, a woman who is 70 kg, 165 cm, 35 years old: 655 + 672 + 297 − 164.5 ≈ 1,460 calories just to exist.

Step 2: multiply by your activity level

BMR is just the baseline. You move, work, exercise — all of these burn more. Multiply your BMR by a factor:

• Sedentary (desk job, little movement): × 1.2
• Light activity (walking, chores, 1–2 workouts/week): × 1.375
• Moderate activity (sport 3–5 times/week): × 1.55
• Intense activity (daily effort): × 1.725

The woman from the example, if sedentary: 1,460 × 1.2 ≈ 1,750 calories per day. This is her maintenance requirement — how much she burns, and how much she can eat without gaining or losing weight. If you’d rather skip the manual calculations, our calorie calculator handles this step automatically.

Step 3: subtract the right deficit

Here’s the part that matters. To lose weight healthily, subtract 300–500 calories from your maintenance requirement. This produces a loss of approximately 0.5 kg per week — because one kilogram of fat equals roughly 7,700 calories, and 500 per day × 7 days = 3,500, meaning half a kilogram.

For the woman from the example: from 1,750, eating 1,250–1,450 to lose weight steadily. No less. Let’s see why.

Why you should NOT drop too low (the myth that ruins everything)

The myth: “fewer calories = faster weight loss, so let me eat 1,000 and be done with it.” This is the most counterproductive idea in the diet world. If you drop below approximately 1,200 calories (women) or 1,500 (men), the following happens, in order:

• Metabolism adjusts — the body becomes more “economical” and burns somewhat less.
• You lose muscle mass, not just fat. And muscle is exactly the tissue that burns calories, so you’re sabotaging your future.
• You’re constantly hungry and, statistically, you give in — one evening of excess cancels three days of starvation.
• The yo-yo effect appears: you regain everything you lost, often with a bonus.

A moderate deficit held for three months beats an extreme deficit held for five days. Always. Weight loss doesn’t accelerate without exacting payment later.

The trick that actually works

Don’t focus only on “fewer calories” — focus on calories that fill you up. 1,500 calories from chocolate leave you hungry an hour later; those same 1,500 from vegetables, soup, lean proteins (chicken breast, fish, eggs, cottage cheese, yogurt), and foods rich in water and fibre keep you full all day. That’s how you maintain the deficit without feeling like you’re struggling — and that’s exactly what separates people who succeed from those who quit.

Frequently asked questions

How many calories do I need to lose weight?

First calculate your maintenance requirement (BMR × activity factor), then subtract 300–500. For most adults, that means somewhere between 1,400 and 1,900 calories per day, depending on size and activity level.

Can I lose weight eating 1,200 calories?

You can, but it’s a low threshold, hard to sustain, and not recommended long-term or without supervision. For most people, a gentler deficit produces similar long-term results with much less suffering and risk.

Does it matter how many times a day I eat?

Not for weight loss. What matters is the total calories per day, not whether you split them into 3 or 5 meals. The myth that “eating frequently speeds up your metabolism” is false — the number of meals doesn’t change how much you burn. Choose what keeps you full and away from endless snacking, whether that’s three or five meals.

Do I have to weigh every food forever?

No. At the start it helps enormously to weigh things for a few weeks, to calibrate your eye — most people underestimate portions by 20–40%. Once you learn what a real portion looks like, you can rely on estimation.

Does the requirement stay the same throughout?

No, and that’s a detail many people miss. As you lose weight, your body becomes smaller and burns less — so your requirement decreases. A person who has lost 10 kg burns less than they did at the start, so the initial deficit gradually shrinks. That’s why weight loss “slows down” after a while: it’s not a failure, it’s physics. The solution isn’t to starve — it’s to occasionally recalculate your requirement at your new weight and adjust slightly.

Put the numbers on paper once and you have a compass for any diet you want to try. You don’t need to be obsessed with calories for life — but a period of a few weeks in which you understand the numbers you’re working with will completely change the way you look at food. Calculate your requirement for free with the calorie calculator, and if you think you’re already eating little and still not losing weight, read why you’re not losing weight even though you eat little.

⚕️ This information is for educational purposes only and does not replace the advice of a doctor or nutritionist. For a personalised plan, especially if you have a medical condition, consult a specialist.