I was actually talking to a lawyer friend of mine about this yesterday. Not this case, just is being overweight a protected class.

Apparently it isn't, it's illegal to discriminate based on ability which might be limited due to your weight depending on how overweight the individual was but the weight itself is not a protected class. It comes up sometimes when people try to do things like sue theme parks because they can't ride the roller coasters. My friend always has to tell them that they don't have a case.

It gets complicated because sometimes somebody cannot be accommodated because they are in a wheelchair or mobility scooter but that in that wheelchair because of their weight rather than any other disability, at which point technically it would be legal to discriminate against them. Although the defense lawyer would have to prove that there was no other mobility issue other than that caused by weight.

Apparently none of this has any precedent though, so it's basically just legal interpretation rather than actual law.