Calorie deficit: what it is and how much you need

Every way of losing weight – from low-carb to intermittent fasting – works through the same thing: a calorie deficit. Here's how to work yours out, and why a smaller deficit often works better.

Information checked on 2026-09-26. General information, not medical advice. How we calculate

In short: a safe deficit is about 300–550 kcal a day less than you need to maintain your weight. That's roughly 0.3–0.5 kg a week. You'll find your own number in the calorie calculator.

What a calorie deficit is

Your body uses energy every day: for breathing, your heartbeat, digestion, walking and exercise. We get that energy from food and measure it in calories (kcal). When you eat as many calories as you use, your weight stays the same. When you eat slightly fewer, your body takes the missing energy from its stores, and your weight slowly goes down. That difference is called a calorie deficit.

How to work out your calorie deficit in 3 steps

  1. Basal metabolic rate (BMR). This is how much energy your body uses at rest. It's usually worked out with the Mifflin–St Jeor formula from your sex, age, height and weight.
  2. Daily needs (TDEE). Your BMR is multiplied by an activity factor: from 1.2 (you hardly move) to 1.9 (heavy physical work). That's how many calories you need to maintain your weight.
  3. The deficit. Take about 300–550 kcal away from your daily needs. But never go below the safe limit: your BMR, and no less than 1,200 kcal for women or 1,500 kcal for men.

An example

A woman, 42, 165 cm, 78 kg, with a desk job but a walk every day (activity factor 1.375):

  • BMR = 10 × 78 + 6.25 × 165 − 5 × 42 − 161 ≈ 1,440 kcal
  • Daily needs ≈ 1,440 × 1.375 ≈ 1,980 kcal
  • With a 400 kcal deficit – about 1,580 kcal a day, which is roughly 0.35 kg a week

This is an estimate, not an exact measurement. Formulas can be around 10% out either way, so after 3–4 weeks it's worth looking at how your weight is changing, and only then adjusting.

Why a bigger deficit isn't better

It seems logical: if a 500 kcal deficit loses half a kilo, then 1,000 kcal should lose a whole one. But in practice, too big a deficit often means:

  • strong hunger and overeating in the evenings or at weekends;
  • tiredness, worse sleep and a lower mood;
  • losing more muscle, especially if you're short on protein;
  • the weight coming back when the “diet” ends.

A smaller deficit looks slow, but you can realistically keep it up for months. And that's exactly what decides the result. More on this in why fast weight loss doesn't work.

How to stay in a deficit without feeling hungry

  • Protein at every meal – eggs, curd cheese (quark), fish, poultry, pulses. They keep you full for longer.
  • Half your plate vegetables. Lots of volume, few calories.
  • Count oil and drinks. A tablespoon of oil is about 90 kcal, and a sugary drink or a coffee with syrup is often 150–300 kcal.
  • A deficit for the week, not the day. One celebration dinner doesn't ruin anything.
  • Move every day. A walk after a meal increases the calories you use and helps you feel better.

You'll find ideas in our low-calorie recipes and high-protein recipes, and a whole week's example in the 1,500 kcal weekly menu.

When to review your deficit

Once you've lost a few kilos, your daily needs go down slightly. If your weight hasn't moved for more than 4 weeks, recalculate your needs for your new weight and look at your portions again. But don't cut calories below the safe limit – it's better to add more movement or simply wait: plateaus are normal.

When to talk to a doctor first

Before you change how you eat to lose weight, talk to your doctor first if:

  • you are pregnant or breastfeeding;
  • you have diabetes or take medicines that affect your blood sugar;
  • you have kidney disease, heart disease or another long-term condition;
  • you are under 18;
  • you have or have had an eating disorder;
  • you are losing weight without trying.

If your relationship with food worries you, you can talk to a doctor or a psychologist. If you're struggling right now, call your local emergency number or find a free helpline at findahelpline.com.

Slowly, but filling. The Dumpli nutrition quiz suggests a safe calorie target and a filling day of meals made from real recipes. Free. Take the nutrition quiz → · Calorie calculator

Frequently asked questions

What is a calorie deficit?

A calorie deficit is when you get slightly less energy from food than your body uses in a day. Your body takes the missing part from its stores, so your weight slowly goes down.

What calorie deficit is safe?

For most people, a safe deficit is about 300–550 kcal a day. That's roughly 0.3–0.5 kg a week. A bigger deficit is only worth using under a doctor's supervision.

How many calories do I need to cut to lose 1 kg?

A commonly used rough figure is about 7,700 kcal per kilogram of fat. For example, a 500 kcal daily deficit is roughly 0.45 kg a week. In real life the pace varies, because your water balance changes and your body adapts.

Why am I in a deficit but my weight isn't moving?

The most common reasons: water and salt change your weight from day to day, portions or oil aren't being counted, you eat more at weekends, or your needs have gone down after losing weight. Look at the trend over 3–4 weeks, not at a single day.

Can I eat less than my basal metabolic rate (BMR)?

We don't recommend it. Dumpli never plans below your BMR, and never below 1,200 kcal for women or 1,500 kcal for men – whichever number is higher.

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