I'm going to tell him to stop eating my food
Why are you going to tell to stop eating your food?
He constantly consumes everything in the fridge
If someone is doing something wrong to you or something that offends you, you should tell them to stop. The person may not be aware of how their actions are affecting you and may continue to do it if you do not speak up.
Yes, and if I don't say anything he will keep doing it all the time and I will starve.
That is sad, he should know better than to be so greedy. He needs to get his own food and keep it on his own shelf in the fridge. Hope he stops after you speak to him, I'm glad you want to talk to him about it.