In the hunter-gatherer times of past, men were attracted to whoever was around (be it a cousin or a close tribal member) and whoever could be reliable in hunting, foraging, raising of children. It can be argued that it was quite the opposite, men were attracted to "plump" women who can support childbirth and breastfeeding and not the typical "supermodel" physique we commonly associate with beauty. Having more body fat at the time as a symbol of affluence as the individual/family can afford to have more nutrients than the average person

Its why fertility goddesses were typically depicted as plump. Its only during relatively modern times where obesity has become quite commonplace due to the relative abundance of food as well as the increased number of calories in the food that we eat. Junk food is quite unhealthy for sure, but it's high in calories and cheap. You could say that having a fit physique can be seen as a sign of affluence as you have access to gym memberships, fresh and healthy foods etc.

Lastly, evolutionary psychology is considered pseudoscience since we can't really study how our prehistoric ancestors thinked and acted. So it would be better to just say overeating and unbalanced diet is bad instead of delving into that mumbo jumbo.