Okay, so you know how when you eat food, you start to feel full and don't want to eat anymore? Well, there's a tiny little thing in your body called peptide yy that helps with that feeling.
Peptide yy is like a messenger that tells your brain that your stomach is full, so your brain knows to stop sending signals to your body to keep eating. It's kind of like a traffic light that goes from green (hungry) to yellow (getting full) to red (full). Peptide yy helps turn the light from yellow to red so your brain knows it's time to stop eating.
Sometimes people who have trouble feeling full enough after eating might have lower levels of peptide yy in their bodies. This can make it harder for their brains to know when to stop eating, which can cause them to overeat. But don't worry, doctors can help figure out ways to increase peptide yy in these cases to help people feel fuller after meals.
So, in short, peptide yy is a tiny messenger in your body that helps your brain know when you're full so you don't eat too much. Pretty neat, huh?