Why Do We Get Hungry?

What You'll Learn

• Food gives your body energy to move, think, and grow
• When your stomach is empty, it sends signals to your brain
• The brain makes you feel hungry so you'll eat and refuel
• A hormone called ghrelin is released when the stomach is empty
• Eating fills the stomach and stops the hunger signal

Words to Know

Hungry

The feeling that tells you to eat

"I felt hungry before lunch."

Stomach

The organ that holds and breaks down food

"My stomach sent a hunger signal."

Energy

The power your body gets from food

"Food gives me energy to play."

Hormone

A chemical messenger in the body

"Ghrelin is a hunger hormone."

Check What You Learned

Fun Facts

• The body needs energy from food to power movement, thinking, growth, and organ function

  Source: Harvard T.H. Chan School of Public Health

• When the stomach is empty, it releases the hormone ghrelin into the bloodstream

  Source: Endocrine Society

• Ghrelin travels to the brain and stimulates hunger and appetite

  Source: National Institutes of Health

• When food enters the stomach and it stretches, ghrelin production decreases

  Source: NIH

• A different hormone, leptin, signals fullness to the brain after eating

  Source: Endocrine Society

• The brain cannot store energy and requires a continuous supply from food

  Source: Harvard Medical School