It’s natural to feel hungry when you need to refuel your body, or to feel satisfied when you are refueled.  But think deeper, how are we able to feel hunger and satiety?  Various organs, chemicals and mechanisms contribute to the feeling you get when either hungry or satisfied.

Hormones signal the satiety (satisfied)  part of the brain, depending on whether the body needs nutrition, or whether it’s satisfied.  The hormone called Ghrelin, sometimes known as the “hungry hormone” is the chemical released by the stomach when the stomach is empty, and it is continued to be released until the stomach is stretched out or satisfied.  When you miss a meal, and begin to feel hungrier and hungrier, it is when ghrelin is collectively released by the stomach.

What about the feeling of satiety?  The hormone insulin, is released by pancreas when blood sugar is too high, and it actually suppresses the appetite.  Figuratively, insulin is telling the brain that it has consumed too much sugar for now, and sending signals for it to not consume anymore until further notice.

There is another hormone called Leptin.  Leptin is released by adipose (fat) tissue, and this chemical also suppresses appetite.  Levels of leptin are actually decreased with loss of weight, which could explain why it is hard to maintain a diet with the intent to lose weight.

Another important hormone is Peptide YY, or PYY.  PYY is secreted by the small intestine when the organism finishes consuming a meal.  PYY counteracts the effects of ghrelin, and suppresses the appetite.

In conclusion, hunger and satiety are much more than just a growl  in the stomach.  There are a lot of chemicals and mechanisms that signal the brain and tell it what the body needs.