Calorie Calculator: Lose Fat, Keep Muscle

Find out how many calories you burn in a day and how much to eat to lose fat without losing muscle. Get your daily calorie target, a protein goal and a realistic timeline to your goal weight.

Please fill in age, weight and height.
Eat this many calories a day
0
0maintenance calories
0 gprotein a day
–to your goal weight
0calories at rest (BMR)
0BMI
0expected change a week

Make it work

  • Lift weights 2–4 times a week so the weight you lose is fat, not muscle.
  • Hit your protein target first, then fill the rest of your calories.
  • Walk 7,000–10,000 steps a day; it adds up more than most workouts.
  • Weigh yourself 3–4 mornings a week and compare weekly averages, not single days.
  • If the scale has not moved in 3 weeks, cut about 150–200 calories or add more daily steps.
Check with your doctor first if you have diabetes, a heart condition, take medication that affects appetite or blood sugar, or have a history of eating disorders.

How this calorie calculator works

Your resting burn (BMR) is estimated with the Mifflin–St Jeor equation, which was the most accurate of the common formulas in a review by the American Dietetic Association. We multiply it by your activity level to get your maintenance calories (often called TDEE).

For fat loss we set the deficit from a weekly rate of 0.5% of your body weight by default. Slower rates of weight loss help protect muscle, and a 2011 study in athletes found that losing about 0.7% a week preserved more lean mass than 1.4% a week. We never suggest less than 1,500 calories a day for men or 1,200 for women. Protein is set at about 2 g per kg (based on a healthier reference weight if your BMI is above 30) to help you keep muscle.

These are estimates. Real burn varies by 10% or more from person to person, so treat the number as a starting point and adjust based on your weekly average weight. Read more: how to lose fat and keep muscle after 35, what really happens to your metabolism after 35 and BMI vs body fat.

Sources

  1. Frankenfield et al. (2005), Journal of the American Dietetic Association: comparison of resting metabolic rate equations
  2. Garthe et al. (2011), International Journal of Sport Nutrition and Exercise Metabolism: effect of two weight-loss rates on body composition and strength
  3. International Society of Sports Nutrition position stand: protein and exercise
  4. CDC: about healthy weight

This calculator gives general education, not medical advice. Check with your doctor before starting a new diet or training plan, especially if you have a health condition.

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