How many calories do you need per day?

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The recommendation to consume between 2,000 and 2,500 calories per day depending on gender is often inaccurate for athletes and physically active adults. These numbers were developed with the average adult in mind and do not account for increased physical activity and the need for increased calorie consumption for improved performance and recovery.

So how many calories do you need per day? Continue reading below to find out.

Daily Energy Requirements

Total daily energy expenditure is determined by your basal metabolic rate along with physical activity and the thermic effect of food.

Basal metabolic rate or resting metabolic rate is basically how many calories you body uses in a 24-hour period to survive and perform daily function. This accounts for 60-70% of your total calorie needs per day.

One study looked at what equation or formula yielded the best estimate for resting metabolic rate among participants and found that the Cunningham equation was the most accurate. However, the authors recommend that you keep in mind that most formulas may underestimate an athlete’s actual energy needs.

The Cunningham equation is

RMR = 500 + 22 * kg of fat free mass

Without using another testing measure such as skinfold testing for bodyfat percentage it can be difficult to estimate fat free mass. However, you can estimate based upon picture comparisons. The picture below does a good job of highlighting the differences.

Visual estimation of body fat percentage
Visual estimation of body fat percentage

Case Study Examples

Using two case examples to explain the Cunningham formula:

  • Male
  • 85kg (187lbs)
  • 20% bodyfat

Fat free mass equals 85kg – 20% = 68kg or 149.6lbs

RMR = 500 + 22 * 68

RMR = 1,996

*Researchers from that study recommend adding 100-300 calories to this total. Therefore, RMR range equals 2,096 to 2,296 calories per day.

  • Female
  • 68.1kg (150lbs)
  • 35% bodyfat

Fat free mass equals 68.1kg – 35 % = 44.2kg or 97.38lbs

RMR = 500 + 22 * 44.2

RMR = 1,472

*Researchers from THIS study recommend adding 100-300 calories to this total. Therefore, RMR range equals 1,572 to 1,772 calories per day.

Physical Activity Level

By now you should have an idea of how many calories you need per day while in a rested state. This is the minimum and assumes you are laying in bed all day and not expending any additional energy through exercise and physical activity throughout the day.

You will need to multiply RMR by a physical activity level (PAL) factor to determine calorie needs dependent upon the amount of activity that you perform each day.

This website does a great job at explaining the information but the main takeaway is

PAL of 1.4 = very low level of physical activity during work or leisure time

PAL of 1.6 (women) or 1.7 (male) = moderate intensity activity

PAL of 1.8 (women) or 1.9 (male) = high levels of physical activity

A second reference I found looks similar but note the slight differences with moderate activity.

Physical activityPAL
Bed rest1.2
Very sedentary1.4
Light activity1.6
Moderate activity1.8
Heavy activity2.0
Vigorous activity2.2
Physical Activity Factor
Source: https://ruralrouterunner.wordpress.com/

The chart above provides a good visual of examples of sedentary and active lifestyles. In my experience I have noticed that most people consider themselves active yet often do not reach the standards for this category.

Using the case examples from above we will see…

The male example with a moderately active lifestyle will need RMR calories per day (1,996 calories) PLUS an additional 1.7x or 70% if we take into account the first PAL chart.

So 1,996 * 1.7 = 3,393 calories per day

The female example with a sedentary lifestyle will need RMR calories per day (1,472 calories)

PLUS an additional 1.4x or 40%.

So 1,472 * 1.4 = 2,060 calories per day

Summary

Now that you understand your calorie requirements per day I will look to expand in future posts about how many macronutrients (protein/carb/fat) you need per day.