Fitness centre, fashion clothes shop assistant. There are loads of jobs where an obese person would not get a look in. Many ladies clothes shops will not have anyone more than a size 10 or 12 working in them.
Maybe more physically demanding jobs - this could be anything where someone is on their feet all or most of the day from gardening to retail to emergency services.
There was a lady on This Morning not long ago who was saying she felt employers did not give her jobs because of her weight. should be easy enough to google (I'm sure I read she got done for shoplifting from a supermarket, possibly before and after the show if it makes the search easier).
Where I worked in care a while back, overweight women could not do the work, they were always having to rest and let the slimmer staff do their share, they weren't popular! we had a lot of stairs and when the emergency bell rings you got to move pretty quick up or down the stairs.
Jockeys! Horse riding jobs in general, mounted police, livery yards... a rider should not weigh more than a certain percentage of the horse's weight for it to be fair to the horse.