It is important to eat enough calories each day to support your bodys basal metabolic rate (BMR) if you don’t your body thinks things have got really tough and there’s a famine going on, after all your body knows you are pretty smart and know how to get it food, your not dumb enough to stop feeding it so it needs to help out. It does that by switching down the metabolism and using energy as slowly as possible. In turn this slows down your fat loss and your functioning, you may find you’re heads a bit foggy, your reponses slowed and energy levels drop.
To achieve optimal fat loss you need to feed your BMR enough calories for its vital functions this still leaves a significant gap between the calories you eat and the amount your body needs for fat loss and you can increase the gap by adding in or increasing your active time and exercise programme.
So what is my BMR, it is the amount of energy your body uses to perform its vital functions such as breathing, heart beat and maintaining the body temperature. This takes 60-70% of the daily energy requirements.
In addition to BMR the body uses energy for physical activity, this is another 20-30% of the required calories and for the thermic effect of food, the energy used to digest it is around about 10% of the calories consumed, it depends a bit on what you eat.
So our minimum level to keep burning is to feed at lest the BMR, for women this is roughly calculated as 655 + (weight in pounds * 4.3) + (height in inches * 4.7) – (4.7 * age in years). For men the calculation is 66 + (weight in pounds * 6.3) + (height in inches * 12.9) – (age in years * 6.8).
To roughly calculate the total calorie burn of the body in a day you can select your activity level and calculate as:
- Sedentry – BMR = 30%
- Moderately active (cardio exercise every second day) – BMR + 30
- Active (cardio exercise every day) -BMR + 50