Americans are fat. Obese. And they seem to be getting ever fatter – as anyone can observe at the local supermarket, K-mart or Walmart. Customers waddle down the aisle gathering junk food, sometimes stuffing it into their chubby faces while the cashier is still ringing them up.

On international flights, it’s obvious, too. As tourists board, certain groups tend to be loud, others rude, but Americans are generally recognizable by their girth – as they wedge themselves into tiny seats while their French, British, Japanese and Chinese companions wince, knowing they’ll not get to use the armrest on this flight.