This week on Newsround we're talking lots about food and what it does to your body.
It's because one in three kids in the UK is now overweight or obese.
In the worst cases and over time obesity can start to cause other health problems like Type 2 diabetes.
But that's very different from Type 1 diabetes, which lots of kids have.
Here Ricky tells you all about obesity, Type 2 diabetes and the affect it can have on people.