You are 100% right in that people treat you differently. 

I have bad knees, a function of having hyper extended them playing varsity softball when in school and being stupid enough to listen to the school trainer instead of seeing an orthopedic.

Fast forward to my mid 30's, post pregnancy, as you said, got caught up in the work eat sleep repeat cycle.  Knees REALLY hurting on a daily basis, otc pain meds and supplements no help, go to an orthopedic, who doesn't even look at the x-rays my gp had taken and tells me to go home and lose weight.

Late 30's another try with a different orthopedic. Same run around to get referrals, same result - dismissed as fat and go away, apparently there were skinny people who needed his help more than I did.

Early 40's, one more try. By then I was walking with a cane. He came in to meet me the first time and I got in his face, told him if he dared tell me to go home and lose weight I would beat him with the cane then report him to the AMA.  He was a tad taken aback and sat down to actually talk to me, injected my knee with cortisone first then sent me for a bunch of pictures, xrays, mri etc.  Bottom line on the next visit he told me I could get Elle McPhearson thin, it would not have helped one bit, I needed surgery.  Losing weight will NOT fix a tear in the cartilage or one in the meniscus.

Funny thing - once I could walk again I started losing weight!

Good for you James  .  You were one of the few that were able to recognise the situation and then do something proactive about it.  Keep working at it, and more important,  keep enjoying life.  Everyone deserves to feel good about themselves and you are obviously doing a great job!!!  Hats off....