Understanding calories & energy balance
Now that you have a good grasp of macronutrients, it’s time to look at calories.
In nutrition, calories refer to energy consumption through eating and drinking, as well as energy usage by the body through physical activity and maintaining normal physiological function.
The human body needs calories (energy) to survive. Without energy, our cells would die, our hearts and lungs would stop, and we would deteriorate.
In most cases, it is important that you consume the number of calories your body needs each day, every day, so that you can enjoy a happy and healthy life. If calorie consumption is too low or too high you will eventually experience physical/hormonal expression, and potentially other health complications.
The number of calories a food contains gives an indication of the energy they possess. Below are the caloric values for our macronutrients:
1 gram of carbohydrate = 4 calories
1 gram of protein = 4 calories
1 gram of fat = 9 calories
When it comes to managing body composition, the amount of calories we consume and the distribution of macronutrients plays a huge role. There are 3 distinct energy environments that influence our bodies very differently.
1. Neutral energy balance
Eat the same amount of energy as you burn to maintain a neutral balance.
2. Positive energy balance
Eat more than you burn, for weight gain.
3. Negative energy balance
Eat less than you burn, for weight loss.
How to determine individual energy requirements
BMR formula
The basal metabolic rate (BMR) refers to the amount of energy your body needs to maintain homeostasis, while at rest. Lots of calculators and formulas are available to calculate your BMR. Keep in mind though, that they are only a hypothetical starting point and they should never be taken as absolute. We recommend that you find a formula and stick with the one system, for the client to maintain consistency with your data.
Some calculators will use weight, body fat percentage and LBM, whilst others will use height, weight, age and gender.
The formula we recommend to use to obtain BMR is the Harris Benedict Formula:
Male: BMR = 66.5 + ( 13.75 × weight in kg ) + ( 5.003 × height in cm ) – ( 6.755 × age in years )
Female: BMR = 655.1 + ( 9.563 × weight in kg ) + ( 1.850 × height in cm ) – ( 4.676 × age in years )
BMR does not take into consideration activity levels, it is only what an individual needs to maintain at rest. Total daily energy expenditure (or TDEE) is the multiplier of activity levels on top of BMR, to give a hypothetical total energy intake.
TDEE multiplier
It is important to understand the lifestyle of a client before giving them a TDEE multiplier.
Non-Exercise Activity Thermogenesis (or NEAT) is the energy expended for everything we do that is not sleeping, eating or training related. An individual who is a bricklayer is going to burn a lot more calories than someone who has a 9 to 5 desk job - no matter how many stairs they tell you they walk up. This will influence TDEE and will usually take a little trial and error to get right. Adjustments will need to be made to an individual's energy prescription based on managing their body composition over a period of time.
Client example
Male: BMR = 66.5 + ( 13.75 × 86 ) + ( 5.003 × 173 ) – ( 6.755 × 32 )= 1,889 Kcal/day
Moderately active: Physical job and workouts out 5 times a week for an hour
= 1889 x 1.88
= 3,551 Kcals/day
(Hypothetical starting point of maintenance/neutral calories)
