<human>: Provide a brief overview of the text.

My boyfriend Lloyd and I are 21 and have been dating 3 years. This summer, I've been trying to get in better shape and eat healthier. I plan to start training for a half marathon when the school year starts up. I have a friend I plan to run with, a training plan, etc. I'm really excited about it and have told my plans to my boyfriend.

My boyfriend wants to join me. He's never been in shape either and wants us to spend more time together, so he thinks running would be a great way to do so.

However, even though I was happy to possibly have his company, I don't know how I feel about him running with me. You see, I'm a bit chubby and could stand to lose some weight, but Lloyd is already really skinny. Most of his calories are from sodas and junk food, and if he plans to cut those out and eat healthy with me, his caloric intake is going to decrease a ton. He tends not to eat if he doesn't like the food, even if he's hungry, so he'll likely skip even more meals if the dining hall food isn't what he feels like. I already feel like he eats way less than most guys his age do.

I also wonder if him running with me will just whittle his size down to nothing. He's very skinny with no muscle and while I like him the way he is now, I don't know how attracted to him I'll be if he ends up losing more weight.

Is there anything I can do about this? Should I tell him I'd rather workout with my girl friend? I don't want to hurt his feelings, but I don't want our sex life to suffer either.
<bot>: Already skinny boyfriend wants to work out/eat healthy with me and become even skinnier. I don't know if I should say or do anything.