I guess posting comments in the CR means I am opinionated. Well, so be it.
I am old enough to have met and known enough people to conclude that personality and midos are not correlated with weight. There are great people who are fat or thin. There are some awful people who are fat or thin. I recall something about a personality theorist who created personality types by body figure. His name has become obscure since there was never any fact to support the theory.
Some of the previous comments push the issues of perception and assumption in either direction. I want to clarify this, having assisted some people in shidduchim, and married off my own children.
There is a myth that the thin girl remains thin throughout life. Believers of that have never heard of baby fat. They also deny genetics.
If I was to encounter a fat prospect (girl or boy), I would be inclined to jump to a conclusion. If the thoughts were verbalized, they would read something like this:
“Wow, that person is really fat. He/she must overeat, make food a priority over other things, and must be so lazy that they never work off the calories ingested. Forget looks, which I might associate negatively. I don’t want to marry someone who prefers a plate of food to me.”
These are judgments that are leaps of faith. Inaccurate, unfair, and not even self-serving.
On the other hand, there are few conditions in which extra weight cannot be dumped. It is not easy, and surgical and radical interventions are not under consideration. Anyone (almost without exception) can lose weight if they truly value that as priority for them. If they are accustomed to being heavy, there would presumably be significant adjustment to a new lifestyle, vis a vis food and exercise, that may well require ongoing help and support to maintain.
My 2 cents worth. Obesity is far more common today, and our eating patterns do not testify for improved health or nutrition. Just visit your favorite kosher grocery. Long, full aisles of nutrition-free junk foods, with the range of flavors and packages growing yearly. I have yet to hear about a kashrus organization that refuses to give hashgocho on another needless, unhealthy form of nosh.