Yeah, no. Both women and men of the middle ages were not bulkier. Nutrition played a huge role at preventing bulk, meat wasn't as readily available.
Not only that, but today we know for a fact that poor nutrition during development years (childhood + adolescence) does cause both significant physical and mental impairment
And we do know for a fact (both from historical sources and examining of mortal remains), that most people from the medieval period did suffer from malnutrition
So, in general europeans back then were both in mind and body less healthy and capable than your average european of today or even from the industrial revolution
Honestly now that I think about it
I remember from 10 years ago, reading some early renaissance knight's martial arts manual
If I remember correctly, there was a passage where he asked his readers not teach his art to peasants, showing nothing but contempt and disgust at them
At the time I thought this was simply aristocratic snobbery
But taking in consideration the facts above, I think it lends a more clear picture of this situation
I mean, imagine you're a well off, educated knight - you're phisically fit, you're literate, you're a reasonably smart individual and possibly even handsome
In comparasion to you, the peasents that work your land are - feeble, slow-minded, short-sighted, iliterate, uncivilized and most likely have the beauty of a toad
In short, they might as well be from another species of human
So, of course it would be natural for a healthy knight to find such creatures repulsive