Why do people gain weight as they age?

20 year old and 40 year old consuming 2,000 calories per day.

At age 20, her body demands 2000 per day.

At 40 it demands 1200 per day.

Typical man consuming 3,000 calories per day from age 20 to 40.

At age 20 his body demands 3000 calories per day.

At 40 it demands 1500.

Their Metabolism slows down...

But what does that mean?

At age 40, your body burns less calories in a day than it did at age 20.

The 3 main things that burn calories are:

a) Basic life support

b) Activity level

c) Total muscle mass

The average person loses up to 1 lb of muscle mass each year from age 20 to 40,

lowering her body's demand for calories

Are you over-eating or under-demanding?