Why did my parents do this?

Ok so yesterday I went to my cousins house to hang out and take a dip in the pool. When I came out of the pool, his mom offered me something to eat. I said "no thanks" and called my parents to pick me up. When I was talking to them they asked if I had eaten. I said no and my mom got mad. My idea was to go eat at my house but mom didnt understand me. So I waited for over two hours to see if they would show up. It wasn't until I called and lied that I eat a bit. I don't see any other parents with the type of mentality that my parents have. My mom always argues about how I don't eat alot. That's because they always force me to eat and make nasty foods as well. Sometimes I just don't understand them... Why would they do something like that? How can I talk to my parents about it?