Well, generally at 5'7 and 175 (listed values) there would not be a real issue with pants labelled as loose-fit.
Not from legs being unproportionally big anyway. Not at that weight.
However it's not unknown for some guys to have ridiculously small waists. Unfortunately, in my gym there was a period when not only was it not unknown, but these idiots wore Spandex shirts to "show off" their girlish waists, so you couldn't help but know. Sorry, a guy looks frail and pathetic with, for example, a 26" waist. For that to be a point of pride is just ridiculous. (And anyway, no spandex on a guy in any case, please.)
Not having specifics, it could be that the OP's problem is instead that his waist needs to man up with some serious deadlifting.
That seems more likely than his legs being hyooge at 175.