My experience is that I absolutely was treated differently when I was obese. I posted the following on a similar thread here a few weeks ago:
I spent many years at a size 24. Total strangers went out of their way to mock, deride and be nasty to me. A few examples:
Guys shouting out of their car windows as they went past, things such as ‘fucking elephant’, ‘hippo’ etc
At a sporting event, as I walked to the stadium, jeers of “here’s our BIGGEST supporter” from a group
A man walking up to me, grabbing me and putting his hands on my hips, then standing back and holding his hands my hip-width apart (though probably exaggerating this in reality) and saying to his friends “go on, guess, how wide is she?”
Making “beep beep, wide load” comments as I went past
That’d just a small selection of the abuse I suffered. Based entirely on how I looked.
Now that I look very different, I don’t get any such abuse from strangers. But hey, it must be all in my head and just to do with my confidence, eh?