Why does he have to pick me up?

it a demonstration of his prowess & power - I think most guys love to do this: it's a throwback to kids - watch fathers (or especially uncles) tossing their daughters around - the girls scream in a combination of fear & joy, and the guys are laughing too because even though they know they're giving a thrill, they know the kid is safe.

"sweep her off her feet" can be a literal thing ;)

it's definitely flirty behaviour - especially with you being on guard: makes it part of the game ;)

i say go with the flow: even if a guy struggles a bit he's not going to make a big deal of it (he'd be thinking more he was weak rather tha you are heavy). I'm not big yet I'll give my 180lbs wife a swing around now & then just to keep her on her toes ;)

enjoy, squeal a bit & even say "put me down" (in the right tone) & it'll be fun for both of you.

I've done that to other girls, it's fun I guess. Kind of like flirting. He might also want to show you he isn't concerned about your weight.

It could be his way to let you know that you're not that heavy, cause if you were so heavy, do you think he would try to pick you up? duh! :)
In other words, is his way to tell you, 'hey, I like how you look.see, you don't weight that much.' I would let him pick you up. If you keep saying no, then you're projecting the idea that there is something wrong with you, so my advice woudl be to just let him do it.

Most guys like to show off their strength. Guys think it's awesome when they can show off that he's holding his girlfriend. Just say I don't wanna be lifted. That's all I can say.

Most guys do that for some unknown reason. Either he's testing his strength or he's trying to prove to you that he doesn't mind your weight and probably showing you that he can lift you probably signifies to him your not heavy and you have nothing to worry about!

Guys never understand this one. That you don't want to be picked up because if you see them struggle at all it will make you feel totally fat. I don't think he's trying to hurt your feelings or anything, he probably just thinks it's fun. And it'd be difficult to explain to him because no guy likes hearing his girlfriend talk about how fat she thinks she is. I'm not sure what the solution is. I was able to just ignore how I felt about it, but I'm also thinner than I was then. If I'd kept the weight on, I don't know that I would've gotten used to him just lifting me whenever he felt like it.