<human>: We've been seeing each other for maybe 4 months now, so it's a fairly new relationship. He's 27m, I'm 24f. 

In short, he makes a lot of comments about being overweight and needing to exercise and eat healthier. This bothers me because I have no idea how to respond to this. I really, really like him, more than I've liked anyone in quite a while, and frankly I want to fuck him or even just get him naked and make out as often as possible as he is. He's not obese or extremely unhealthy, just maybe 10-15lbs over 'skinny', and he's not living off of fast food or sitting on his ass all day, so I'm not very concerned about his actual health. I think it's great if he wants to get in shape or eat better or whatever, and I'm fine with being supportive or cooking healthier meal at home instead of going out. I've suggested it a few times, and we've done it here and there, or if we do go out, he'll make a fairly healthy choice from the menu (grilled salmon and walnut salad or the like), but he's not strict about it either. 

So basically all is well and I'm being supportive but I just freeze whenever he's like 'My body isn't what it used to be' or 'I didn't go to the gym this week and I really should have..' or even just 'I really need to lose weight, I'm not used to looking this way, it's not how I normally look'. I'm not sure if he's trying to make sure I still like him or venting or what's going on, but what the hell do I say or do when he comes out with shit like that? I don't want to just say 'I think you're sexy' because I admire his efforts to get himself wherever it is he wants to be, and also because it doesn't really seem to do much, he just laughs it off like I'm joking.

Can you give me a shortened version of the text?
<bot>: bf keeps making comments about being fat, I think he's hot and like to get naked with him, what do I say/do when he says these things?