Narrator: Why is it so hard to keep the pounds off?
Well, there's more to weight management than meets the eye.
People may see results when they limit calories,
by reducing the size of meals, for example,
and find ways to increase physical activity,
like taking regular walks around the block,
but the body reacts to weight loss
by trying to regain weight,
making weight management a constant tug of war.
Metabolism slows down and gets more efficient,
requiring fewer calories to do its job.
Hormonal signals can also change.
The body increases a hunger hormone,
called the ghrelin hormone,
which tries to get you to eat more calories,
and the hormones that tell the brain
it's time to stop eating,
the feeling full signals, decrease.
These are just some of the factors
that make weight regain so common.
(calm music)