How Many Calories Do I Need a Day? And What Is a Calorie Deficit?

Most adults need 1,600 to 2,400 calories a day for women and 2,000 to 3,000 for men, depending on age, size and activity1. Your own number takes two steps: the energy your body uses at rest, then times your activity factor. For example, a 30-year-old woman who is 160 cm (5′3″) and 60 kg (132 lb) needs about 1,550 calories if she mostly sits, and 2,000 if she exercises 3 to 4 times a week.

As a rough average, the NHS uses 2,000 calories for a woman and 2,500 for a man2. It's better to know your own number, and this article shows you how, step by step, the same way Sufra works out your plan.

How to work out the calories your body needs

Sufra uses the Mifflin–St Jeor equation, one of the most widely used ways to estimate the energy your body burns at rest3. It takes two steps.

Step 1: your energy at rest

For the woman: 10 × 60 = 600, 6.25 × 160 = 1,000 and 5 × 30 = 150. So 600 + 1,000 − 150 − 161 = 1,289 calories: what her body uses at rest over a whole day.

Using pounds and inches? Divide pounds by 2.205 to get kilograms, and multiply inches by 2.54 to get centimeters.

Step 2: multiply by your activity factor

Sufra rounds the result to the nearest 50 calories, because it's an estimate, not a measurement. Sufra asks you these same questions when you first open it and gives you your number right away.

Table: daily calories by body and activity

Six examples worked out with the same equation. Find the one closest to you, or work out your own with the two steps above.

Notice how much activity moves the number: the same person needs 450 to 700 more calories when they go from mostly sitting to exercising 3 to 4 times a week. Age brings it down a little: 5 calories less for each year, before the activity factor.

Equations differ a little from one another, and so do bodies. Treat any number as a starting point: watch your weight for two or three weeks, then adjust.

What is a calorie deficit?

A calorie deficit means eating less than your daily need, so your body takes the difference from its stores. The usual rule of thumb is that a kilo of body weight is about 7,700 calories (about 3,500 per pound), so a deficit of 550 calories a day comes to half a kilo (about a pound) a week on paper.

But it's only a rule of thumb: as weight comes down, the body uses less energy, so the change slows over time4. The scale also moves every day with water and salt, so the trend over several weeks matters more than any single day.

How big a deficit?

In Sufra you pick the pace yourself. Here it is for a man whose daily need is 2,400 calories:

Steady is the one we recommend. Fast means more hunger; you can start steady and speed up later.

The usual minimum: 1,200 for women, 1,500 for men

Calories shouldn't go below 1,200 a day for women or 1,500 for men unless a health professional is guiding you5. That's why a Sufra plan never goes under that line, even at the fastest pace. For example, the woman in our example (1,550 calories, mostly sitting) who picks half a kilo a week gets a plan of 1,200 calories, not 1,000.

When not to cut calories

In these cases Sufra gives you a maintenance plan with no deficit, and we suggest you talk to your doctor before any diet:

• You're under 18.
• You're pregnant or breastfeeding.
• You have diabetes.
• You've had an eating disorder.
• Your BMI is under 18.5 (underweight).

How to split your calories between protein, carbs and fat

Each gram of protein or carbohydrate has 4 calories, and each gram of fat has 9. Sufra splits your goal into 25% protein, 45% carbs and 30% fat, all within the acceptable ranges for adults: protein 10 to 35%, carbs 45 to 65% and fat 20 to 35%6.

For a goal of 1,850 calories: 1,850 × 25% ÷ 4 = about 116 g of protein, which Sufra rounds to 115.

What does 1,850 calories look like in a day?

An example day of Arabic food, with numbers from Sufra's food table (sources in our article on calories in Arabic food):

That's 1,820 calories, just under the 1,850 goal. Swap in whatever you like: what matters is staying close to your goal across the week.

This is general information, not medical advice, and every number is an estimate. If you have a health condition, ask your doctor or a dietitian before any diet.

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