Why do we get sleepy after eating a big meal?

Have you ever eaten a big meal and become sleepy immediately after, even if you weren't tired when you first sat down? It wasn't all the fork and spoon lifting that did it!

The two organs in your body that require the most energy to work properly are the brain and the intestines. When you eat, your brain diverts energy towards digestion, sending a bunch of red blood cells over to help break down the food and carry the nutrients all over your body! Because so many blood cells are helping out the intestines, the rest of your body takes this time to slow down and relax. As a result, you might feel tired, since your brain doesn't have as many blood cells to help it out at the moment — more energy used for digesting food means less energy can be used for running around!