Dear 100 Hour Board,
So there's this guy I really like being around and we've started dating. I love his personality, his patience, his consideration for others. He's sweet, clever, and we have a lot of common interests... we're basically best friends. But we have different ideas of what's physically attractive. I find lean figures attractive, so I try to keep myself trim. He finds rounder bodies more attractive and aspires to gain more weight. I'm... not sure what to do with this. I'd like to keep dating him and progress in the relationship, but the fact is my physical wants and his physical wants are polar opposites. I love him as a person but I will never be attracted to the type of body he wants to have. Asking him to change his body for me feels wrong, because I want him to love himself. I don't want to hurt him by breaking it off, but I also want to be attracted to my partner and he certainly deserves someone who's attracted to him. What do I do?
-The biggest loser
I would suggest having a discussion about health.
Regardless of physical preferences in terms of aesthetics, for the most part it is not healthy to gain weight. It's definitely possible to do so while still exercising and eating relatively healthy, if you consume enough calories, but overall wanting to gain weight will likely have a detrimental effect on health. So while this doesn't sound like the most fun discussion, I think it's an important one to have. You shouldn't ask him to change his body just for you, but explain that if your relationship lasts, you want to have a long relationship, not one that ends with a heart attack at 43.
I would also suggest just having a conversation with him about your feelings on this topic in general. If you jump right into talking about your concerns for his health, without ever having discussed the concerns you mention in this question, he might not have a full idea of what you're actually thinking, and it could seem a little pushy and over-reaching for you to start dating him and then immediately talk about how worried you are about his health. Relationships are all about communication, though, so just tell him how you're concerned about your different goals for weight gain/loss, and wondering about what that means for the two of you. Heck, you could even just tell him exactly what you wrote in this question. But you have to let him know how you're feeling, because then the two of you can make a decision about what to do together. Your relationship with him is between the both of you; involve him in the decision making process.