A person, typically seen in and around malls (and WalMarts) in the suburban United States, so obese that they "earn" a handicapped permit for their car, and the parking privileges that come with it, at the expense of the truly challenged. Fattycapped people often get around in motorized wheelchairs likely paid for by health insurance because they are so huge they can no longer walk. This "disease" is often blamed on "genetics," yet is rarely seen outside the US where all genetic types are represented.
"Look at that poor person in the wheelchair pre-boarding the airplane."
"Don't feel sorry for her, she's fattycapped. See? She just got out of the chair and is walking down the aisle where she will get two seats for the price of one."