Fat loss starts with an accurate calorie target — not a random 1,200 kcal plan from social media. The Mifflin–St Jeor equation is widely used by coaches because it estimates resting energy expenditure from your age, height, weight, and sex, then adjusts for activity.
Step 1: Estimate your BMR
For men: (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5. For women: substitute −161 at the end. This gives you basal metabolic rate (BMR) — calories burned at rest.
Step 2: Multiply by activity
Sedentary ×1.2, lightly active ×1.375, moderately active ×1.55, very active ×1.725. The result is maintenance calories.
Step 3: Apply a deficit
Most people do well with a 15–25% deficit (roughly 300–500 kcal below maintenance). Pair it with 1.8–2.2 g protein per kg bodyweight to protect muscle while dieting.
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Frequently asked questions
How do I calculate my calorie deficit?
Estimate maintenance calories using the Mifflin-St Jeor equation multiplied by an activity factor, then subtract 15 to 20 percent. For most people this produces a deficit of roughly 300 to 500 kcal per day and around 0.5 to 1 percent of bodyweight lost per week.
How fast should I lose weight?
Around 0.5 to 1 percent of bodyweight per week. Faster rates increase muscle loss and are harder to sustain, while slower rates may not produce visible progress quickly enough to maintain motivation.
Why is my calculated calorie target not working?
Equations estimate maintenance within roughly 10 percent, so individual variation is expected. Track your weekly average weight for two to three weeks and adjust your intake based on actual results rather than the calculated number.