Different people

My boyfriend and I are two completely different people and most of the time it works greatly. I used to weigh a lot but I've dropped a significant amount of weight and now I LOVE healthy food, working out, and staying fit. However, my boyfriend does not. He talks about needing to but will continually eat out all the time and eat a lot of food. There's only so much you can say to someone without being offensive but I'm worried about his health. I want to be able to do things with him outside and participate in healthy things. Help!