I personally was average athletic weight for most of my life. About 170-180lbs while being about 5'11" height. For the last 5 years I have been between 200-220lbs and there is a noticeable but subtle difference in the way I am treated. Most people do not say hey Cram you are looking heavier but I do for instance hear, you have lost some weight it looks good, keep it up. So clearly the weight is noticeable.
The most noticeable difference is how I view myself and this is likely an extension of how broadly I am seen. While I certainly could be fatter and do not qualify as clinically very obese I do though feel unhealthy and unhappy about the situation and struggle at times to stay focused on getting to that healthier weight. Part of it is my age, I'm 42 now and things shift metabolically, my work is not physically active and some injuries from my active years (play rugby) have slowed me down. Nevertheless I suspect there is at least a slight negative in the way some people treat me because of my weight and perhaps significant by some. I personally notice people and their body condition is often reflective of a personality trait, though of course not always. This said it is possible that I am projecting my own feelings upon others and I am not being treated differently.