How to Calculate Calorie Deficit for Weight Loss

Medically Reviewed on 10/7/2021
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Calorie deficit means consuming fewer calories than your body uses in a day. To calculate your calorie deficit for weight loss, follow these two basic steps

Calorie deficit means consuming fewer calories than your body uses in a day. To calculate your calorie deficit for weight loss, follow these two basic steps:

Step 1: Calculate your maintenance calories

The first step to calculating your calorie deficit is to find out how many calories you need in a day to maintain your weight, also called maintenance calories.

Multiply your weight by 15

A rough estimate for calculating maintenance calories for a moderately active person is multiplying body weight in pounds by 15 (you roughly need 15 calories per pound of your body weight to maintain your current weight). 

Moderately active means engaging in physical activity equivalent to walking about 1.5-3 miles a day at 3-4 miles an hour, in addition to daily living activities. 

So, if you weigh 150 pounds, your maintenance calories will be 150 × 15 = 2,250 calories.

Figure out your BMR and TDEE

Another way to calculate your maintenance calories is knowing your basal metabolic rate (BMR) and total daily energy expenditure (TDEE). 

BMR is the number of calories needed to maintain the basic life-sustaining functions, such as breathing, maintaining blood pressure, and digesting food. One popular formula for calculating BMR is the Harris-Benedict formula. According to this formula:

  • BMR for males = 66 + (6.23 × weight in pounds) + (12.7 × height in inches) − (6.8 × age in years)
  • BMR for females = 655 + (4.3 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)

Next, you need to calculate your TDEE, which is the total number of calories you burn including your BMR. Your TDEE equals your maintenance calories. To calculate your TDEE:

  • TDEE = 1.2 × BMR if you have a sedentary lifestyle (little to no exercise and work a desk job)
  • TDEE = 1.375 × BMR if you have a lightly active lifestyle (light exercise 1-3 days per week)
  • TDEE = 1.55 × BMR if you have a moderately active lifestyle (moderate exercise 3-5 days per week)
  • TDEE = 1.725 × BMR if you have a very active lifestyle (heavy exercise 6-7 days per week)
  • TDEE = 1.9 × BMR if you have an extremely active lifestyle (strenuous training 2 times a day)

Step 2: Calculate your calorie deficit

According to the American Heart Association, you need to eat 500 calories less than your maintenance calories a day to lose 1 pound of weight a week.

So, if your TDEE is 2,000 calories, eating 1,500 calories a day for 7 days may help you achieve a weight loss of 1 pound a week as long as you keep your daily activities consistent. Increased physical activity means more weight loss

If you are a beginner, you can start with a deficit of 200 to 300 calories initially and then build up to eating 500 to 750 calories under your maintenance calories.

How does a calorie deficit work?

Calories have two outcomes: either they are used for work and body functioning, or the excess calories get stored primarily as body fat. If you consume more calories than you use, you are bound to gain weight no matter what type of diet you follow.

The number of calories you need in a day is determined by several factors, such as:

  • Age
  • Gender
  • Weight
  • Height
  • Physical activity
  • Basal metabolic rate
  • Underlying health conditions
  • Body composition (primarily muscle mass and fat percentage)

How much weight can I safely lose in a week?

For sustainable and safe weight loss, it is advisable to aim for losing about 1-2 pounds a week. This means eating 500 to 1000 calories below your maintenance calories a day. 

Along with losing weight, it’s important to make sure to eat healthy, exercise, get enough sleep, manage stress, and drink plenty of water for overall health.

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Medically Reviewed on 10/7/2021
References
U.S. Food and Drug Administration. Do You Know How Many Calories You Need? https://www.fda.gov/media/112972/download

Müller B, Merk S, Bürgi U, Diem P. Berechnung des Grundumsatzes bei schwerer und morbider Adipositas [Calculating the Basal Metabolic Rate and Severe and Morbid Obesity]. Praxis (Bern 1994). 2001 Nov 8;90(45):1955-63. German.. https://pubmed.ncbi.nlm.nih.gov/11817239/

NASM's Calorie Calculator. https://www.nasm.org/resources/calorie-calculator

Mayo Clinic. Weight Loss: 6 Strategies for Success. https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/weight-loss/art-20047752

Harvard Health Publishing. Calorie Counting Made Easy. https://www.health.harvard.edu/staying-healthy/calorie-counting-made-easy