How Many Calories Should You Eat to Lose Weight?

You've probably seen the "eat 1,200 calories a day" advice everywhere. For most adults, that's far too low — and counterproductive. Here's how to actually calculate your calorie target for weight loss without trashing your metabolism or losing muscle.

Step 1: Find Your Maintenance Calories (TDEE)

Before you cut anything, you need to know how many calories your body currently needs to stay exactly as it is. This is your Total Daily Energy Expenditure (TDEE) — and it's different for every person.

TDEE is made up of four components:

• BMR (Basal Metabolic Rate) — calories burned just existing: breathing, organ function, keeping warm
• NEAT (Non-Exercise Activity Thermogenesis) — walking, fidgeting, general movement throughout the day
• EAT (Exercise Activity Thermogenesis) — deliberate workouts
• TEF (Thermic Effect of Food) — calories burned digesting food (~10% of total intake)

For most people, TDEE lands somewhere between 1,600 and 3,000 calories depending on size, age, sex, and activity level. A 5'4" sedentary woman in her 40s might have a TDEE of 1,700. A 6'1" male construction worker in his 30s could be above 3,000.

Step 2: Apply a Sensible Deficit

One pound of body fat contains roughly 3,500 calories. To lose 1 lb per week, you need a daily deficit of 500 calories. To lose 0.5 lb per week, a 250-calorie deficit.

Most dietitians recommend a deficit of 300–600 calories per day. This produces steady, sustainable loss of 0.3–0.7 kg per week without triggering significant muscle loss or hunger hormones that cause rebound eating.

Why 1,200 Calories Is Often Too Low

The "1,200 rule" comes from old research on very-low-calorie diets. It's become a default number that stuck — but it's only appropriate for very small, very sedentary individuals.

Eating too far below your TDEE causes problems:

• Muscle loss — your body breaks down muscle for fuel when calories are too low
• Metabolic adaptation — your TDEE itself starts to drop after weeks of severe restriction
• Hunger hormone changes — ghrelin (hunger) goes up, leptin (satiety) goes down, making you more likely to binge
• Nutrient deficiencies — hard to hit protein, fibre, and micronutrient targets below ~1,400 calories

The Role of Protein

When cutting calories, getting enough protein is non-negotiable. Protein has three key advantages in a deficit:

• It preserves muscle mass — your body will strip muscle if protein is too low
• It's more satiating than carbs or fat — you feel fuller on fewer calories
• It has a higher thermic effect — you burn roughly 25–30% of protein calories just digesting it

Aim for 1.6–2.2g of protein per kilogram of bodyweight when in a calorie deficit. For a 75kg person, that's 120–165g per day.

A Realistic Example

How to Adjust Over Time

Your TDEE changes as your weight changes. Every ~5kg of weight lost, recalculate. A deficit that produced 0.5kg/week at 90kg may produce only 0.3kg/week at 80kg — because you're now a smaller person who needs fewer calories just to function.

Plateaus are normal. They usually mean it's time to either reduce intake slightly, increase activity, or take a two-week "diet break" at maintenance calories to reset hunger hormones before continuing.

The Quickest Way to Calculate Yours

The most accurate method is using the Mifflin-St Jeor equation to find your BMR, then multiplying by an activity factor for TDEE. The calculator linked below does this automatically — enter your stats and it gives you a target adjusted for your goal.