When people feel occasionally sick
after eating, they may
throw up or try to, to rid their body of the harmful food. It's not forceful, but more like a "get me to the bathroom or I'll spew all over you."
If you're doing it all the time, and you can control when you throw it up (like you can make it to the bathroom and stick your finger down your throat to make yourself throw it up) then it's something deeper. It could be in your head. It could be an eating disorder.