Back

Generally, body fat is a mass of fat cells, small blood vessels called capillaries, and small amount of water. This mass is known as adipose tissue.

This is a photograph of a rubber model of 1 pound of adipose tissue.

One pound of this adipose tissue is around 3500 kilocalories.To find how long it takes to burn that, first, you have to figure out how many calories you've burned.

Say, for instance, you like to ride your bike at a moderate pace for leisure. You do this for around an hour every day.

The MET value of moderate, leisurely bike riding is 8.0. If a 154lb/70kg man did this everyday for an hour...

8.0 x 70 = 560

...he'd burn 560 kilocalories. Now, to find out how long he'd have to do this to burn a pound of adipose tissue, you divide the amount of kilocalories in one pound of adipose tissue by the amount of calories he burns in one hour...

3500 / 560 = 6.25 hours

Okay, our guy burns a pound of fat every six days theoretically if he keeps his routine up.