Activity

Dissecting TDEE

If we break TDEE down into it's components we get the basal metabolic rate (BMR) and physical activity levels (PAL):

Basal Metabolic Rate: BMR (~80%)

Daily BMR is practically the same for an individual day after day. It's quite static. The majority of the calories you burn that factor into BMR are due to liver, brain, heart, and kidney normally operating.

BMR is different for different people based on their weight, height, body fat percentage, and thyroid activity however.

What's important is to recognize a significant amount of calories are burnt even if you don't ever get out of your bed that day. It's energy to simply keep you alive.

Physical Activity Levels: PAL (~20%)

Unless you're an athlete or have a very active job PAL probably won't make up much of your daily energy expenditure. PAL consists of two main components:

• NEAT = Non-Exercise Activity Thermogenesis a.k.a. non-intentional activity
  • brushing your teeth
  • walking around the house
  • fidgeting your leg
  • typing
• EAT = Exercise Activity Thermogenesis a.k.a. intentional activity
  • going for a run
  • lifting
  • swimming
  • jogging

If you don't exercise in a given day your TDEE = BMR + NEAT. A common estimate for NEAT is 20% of your BMR. For example, if your BMR is 1800 calories your NEAT is likely about 360 calories. That's because:

1800 calories * 120% = 2160 TDEE

2160 - 1800 = 360 calories NEAT

On the days you do exercise, EAT usually contributes between 250 to 500 calories a day per hour of intense exercise. That's actually not that much for a whole hour of work! About a protein bar or several eggs extra a day. So if your BMR + NEAT is 2160 calories, on the days you lift for an hour your TDEE would be about 2,160 + 250 = 2,410 calories total.