According to some figures, the average American is now overweight. Among some population subgroups, 50% are obese. Public spaces, particularly seats, are designed for the average human being, so seats are now being made larger.
Social taboos, such as publicly acknowledging someone's culturally undesirable obesity, encourage a general need for larger furniture. It is less embarrassing to provide everyone in a room with large chairs than to especially supply only the heavier people with big chairs.
Office furniture was previously designed not to break under weights of less than 95 kg; now it is made for weights up to 160 kg. Restaurants often keep armless chairs for clients who can't fit between the arms of regular seats. Car occupants are now assumed to be 8 kg heavier, and aircraft passengers 9 kg heavier, than they were 40 years ago. Clothing sizes may also change.