The recommended daily calorie intakes may vary for each person depending on several factors, such as: age, size, height, sex, lifestyle, and overall general health. Recommended daily calorie intakes also vary across the world. The National Health Service (NHS), UK, suggests that the average male adult needs approximately 2,500 calories per day to keep his weight constant, while the average adult female needs 2,000. US authorities recommend 2,700 calories per day for men and 2,200 for women.
The NHS stresses that rather than precisely counting numbers (calories), people should focus more on eating a healthy and well balanced diet, being physically active, and roughly balancing how many calories are consumed with the numbers burnt off each day.
According to the United Nation’s Food and Agriculture Organization (FAO), the average person’s minimum calorie requirement per day globally is approximately 1,800 kilocalories.
How many calories do I need per day?
The Harris-Benedict equation, also known as the Harris-Benedict principle, is used to estimate what a person’s BMR (basal metabolic rate) and daily requirements are. The person’s BMR total is multiplied by another number which represents their level of physical activity. The resulting number is that person’s recommended daily calorie intake in order to keep their body weight where it is.
This equation has limitations. It does not take into account varying levels of muscle mass to fat mass ratios – a very muscular person needs more calories, even when resting.
How to calculate your BMR
- Male adults
66.5 + (13.75 x kg body weight) + (5.003 x height in cm) – (6.755 x age) = BMR
66 + ( 6.23 x pounds body weight) + ( 12.7 x height in inches ) – ( 6.76 x age) = BMR
- Female adults
55.1 + (9.563 x kg body weight) + (1.850 x height in cm) – (4.676 x age) = BMR
655 + (4.35 x kg body weight) + (4.7 x height in inches) – (4.7 x age) = BMR
Applying levels of physical activity to the equation
- Sedentary lifestyle – if you do very little or no exercise at all
Your daily calorie requirements are BMR x 1.2
- Slightly active lifestyle – light exercise between once and three times per week
Your daily calorie requirements are BMR x 1.375
- Moderately active lifestyle – if you do moderate exercise three to five days per week
Your daily calorie requirements are BMR x 1.55
- Active lifestyle – if you do intensive/heavy exercise six to seven times per week
Your daily calorie requirements are BMR x 1.725
- Very active lifestyle – if you do very heavy/intensive exercise twice a day (extra heavy workouts)
Your daily calorie requirements are BMR x 1.9