Here it is, the looming threat of a possible love rival to push the male lead into taking action. Haruki already has that in the form of Minamo, so it's Hayato's turn to feel a little threatened, I guess. Her current policy of not dating anybody is a double edged sword though. On one hand, it means the soccer club guy won't succeed if he confesses, but on the other hand it also prevents Hayato from considering it himself, keeping the status quo.
Haruki's too hung up on her weight when's she's looking great. Even better, it seems it was mostly lean muscle and not fat, shouldn't have to worry about becoming flabby or anything. But worrying about gaining weight is a tale as old as time when it comes to teenage girls in manga/anime...