Darlene Cates (who was in the movie "What's Eating Gilbert Grape?"
was large but still could get around fine and had no serious problems with it. Then she broke her ankle and was bedridden for a few months. She gained more weight as a result and even after her ankle healed was barely able to walk. She was not happy about that so I would call that "too fat". Of course maybe it helped her get that movie role, so there might have been some upside!