calculate your calories

Step 2: Calculate your calories

Baffled by why your numbers are so much lower than the 8,700 kJ espoused by nutrition panels? Don’t panic, we’re not done. That’s just what you burn to maintain basic bodily functions (what you’d burn if you stayed in bed for 24 hours). Known as basal metabolic rate or BMR, it comprises just 65 per cent of daily energy usage.

Next, you’ll add other energy usage to come up with how many kJs you burn on average per day (total daily energy expenditure or TDEE). Care factor? From that, you can work out how many kJs you need to cut to lose a kilo. Physical activity represents 25 per cent of energy usage and the thermic effect of food (see p. 89) takes about 10 per cent.

To calculate your TDEE, multiply your BMR by your activity level according to these numbers.

Sedentary = BMR x 1.2 (little or no exercise, desk job)
Lightly active = BMR x 1.375 (light exercise/ sports 1–3 days/week)
Moderately active = BMR x 1.55 (moderate exercise/ sports 6–7 days/week)
Very active = BMR x 1.725 (hard exercise every day, or exercising 2 xs/day)
Extra active = BMR x 1.9 (hard exercise two or more times per day, or training for marathon, or triathlon, etc.)

e.g. If your BMR is 4,519 kJ and you’re lightly active, your activity factor is 1.375, making your TDEE 1.375 x 1,081.2 or 4,519.4, or 1,486.5 calories/6,214 kJ. In theory consuming 6,214 kJ each day (averaged) will maintain your current weight. Add an intense workout to up your food budget.