How to Calculate & Maintain a Sustainable Calorie Deficit

Weight Loss•5 min read•Oct 2026

A calorie deficit simply means eating fewer calories than your body uses. The size of that deficit decides whether weight loss feels manageable or miserable, and whether you keep muscle while you lose fat.

Step 1: Find your maintenance calories

Start with your Total Daily Energy Expenditure (TDEE), the calories you burn in a day. Our calorie calculator estimates this with the Mifflin-St Jeor equation and your activity level.

Step 2: Choose a moderate deficit

A deficit of about 300–500 kcal per day is a common, sustainable starting point. It typically supports around 0.25–0.5 kg (0.5–1 lb) of loss per week. Larger deficits can work short term, but they make hunger, fatigue and muscle loss more likely.

Step 3: Protect muscle

Keep protein high, roughly 1.6–2.2 g per kg of body weight.
Do resistance training two to four times a week.
Sleep seven to nine hours when you can.

Step 4: Adjust using real results

Every calculator gives an estimate. Track your weight weekly and compare the average over two to three weeks. If nothing has changed, trim intake slightly or add daily movement. If you lose faster than planned or feel run down, eat a little more.

Avoid dropping below recommended minimum intakes without medical supervision.

This guide is for education only and is not medical advice. Consult a licensed professional before changing your diet or exercise routine.