The Maths
The first step when trying to calculate daily calorie intake is to work out your BMR, or Basal Metabolic Rate. This tells you how much energy your body will use if you were in a state of rest within a 24hr period.
BMR (Basal Metabolic Rate) for Women
BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years )
or
BMR = 655 + ( 9.6 x weight in kilos ) + ( 1.8 x height in cm ) - ( 4.7 x age in years )
BMR (Basal Metabolic Rate) for Men
BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in year )
or
BMR = 66 + ( 13.7 x weight in kilos ) + ( 5 x height in cm ) - ( 6.8 x age in years )
Once you know your BMR, the next step to determine your total daily calorie needs is to multiply your BMR by the appropriate activity factor, based on the amount of movement you do each day:
- If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
- If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
- If you are moderatetely active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
- If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
You can then use this value to work out your macronutrient needs:
- Protein (4 calories/gram) intake for most should be 0.65g/lb bodyweight to maintain muscle mass, whereas athletes and weight lifters should aim for 1g/lb
- Fat (9 calories/gram) should form around 25% of your calories
- The rest of your calories should be used for Carbohydrates (4 calories/gram)
