Your TDEE is your total daily energy expenditure, this is simple the amount of calories which your body burns in a day. This is calculate using a formula which combines your BMR (basic metabolic rate) and your activity levels.

Basal Metabolic Rate is the amount of calories your body needs to function when resting, just to keep your organs functioning. This equates to about 60% of your total calorie intake. There are lots of different online calculators which will help you to calculate your BMR using your height, weight, age and gender.

Your activity levels are rated as follows:
1.2 - for low intensity and leisure activities
1.375 - for light exercise (approximately 30 minutes to an hour walking, 3-4 days a week)
1.55 - moderate exercise 3-5 days a week
1.725 - active and exercising 6-7 days a week
1.9 - intense exercising 6-7 days a week, the athletes amongst us!

This is then multiplied by your BMR (BMR x activity levels) to give you your TDEE. However, everyone is different so it may calculate to be too high or too low for some people, and it is of course difficult to categorise your activity levels for an accurate result.

To lose fat, a safe calorie deficit would be to cut around 500 calories a day from your TDEE which would work out at 3500 less calories a week. However, this may vary depending on your body fat percentage.

To gain weight you would need to do the opposite and increase your daily calorie intake, as well as working hard and effectively at the gym!

Beth x

Photo Credit: http://www.gritcityfitnessandperformance.com/do-you-know-what-tdee-is/