Calorie deficit explained: how big should yours be?

What a calorie deficit is

A calorie deficit simply means eating less energy than your body uses. To make up the difference, your body draws on its stored energy, and over time your weight comes down.

It’s the common thread behind almost every weight-loss approach. Low carb, intermittent fasting and smaller portions look different on the plate, but they mostly work by helping you eat a little less than you burn.

The energy you burn in a day is your maintenance number. If you don’t know yours yet, start with how many calories you should eat a day.

How big it should be

A moderate deficit is the one you’ll keep. For most people that means eating about 10–20% below maintenance, often somewhere around 300–500 calories a day.

You may have heard that 3,500 calories equals a pound of fat (about 7,700 per kilogram), so a 500-calorie daily deficit loses a pound a week. It’s a handy sketch, but not a schedule. Weight loss tends to slow as you get lighter and your body adapts, so expect the pace to ease over time.

Going much lower rarely pays off. Very small intakes are hard to sustain, make it tough to get enough protein and nutrients, and often end in a rebound. As a general rule, don’t go below about 1,200 calories a day for women or 1,500 for men without medical supervision.

Why the scale jumps around

Your weight can swing by 1–2 kg (2–4 lb) from one day to the next without any change in body fat. Water, salt, carbohydrates, what’s still being digested and, for many women, the menstrual cycle all play a part.

• Weigh yourself in the same conditions, such as first thing in the morning.
• Watch the weekly trend, not single readings.
• Give it two to three weeks before deciding whether your deficit is working. A big drop in the first week is often mostly water.

Make it easier to keep

• Keep protein up. It helps you stay full and hold on to muscle; see how much protein you need.
• Fill up on volume. Vegetables, fruit, soups and salads add bulk without many calories.
• Keep the foods you love, in portions that fit. Banning favourites rarely lasts.
• Plan for weekends and evenings. Your weekly average matters more than any single day.
• Sleep. Short nights make hunger and cravings louder.

If you have a medical condition, are pregnant or breastfeeding, or have a history of disordered eating, talk to a doctor or dietitian before starting a deficit.

Follow it in Meali

Choose Lose weight in Meali’s Nutrition goals, and Meali sets a starting target 10% below your estimated daily burn: a gentle deficit with no fixed deadline. When you reach your target weight, it moves you to maintenance automatically.

Then just log your meals in your own words. Your daily summary shows how each day compares, Progress shows your week at a glance, and Weight tracking draws a trend line through the daily ups and downs, so you can see real progress instead of chasing the scale.