The answers are many; some complex, some simple.
Have you been shopping for china or stoneware recently? I have. The trend is toward HUGE plates. Salad plates are the size of what I'd consider a dinner plate, and what passes for a dinner plate these days is the size of a serving platter. Bowls are deep, cavernous pits. Check out your local Pottery Barn, Crate and Barrell, etc., when you have a chance. These huge dinning pieces have the insidious effect of making you want to fill them up. It's the little things that are making people so big.
Yesterday I was tooling around the touristy part of San Francisco on my bike, from Fisherman's Wharf and Pier 39 to the Golden Gate Bridge visitors' center. I saw a fair number of tourists on rented bikes, but I also noticed a new trend: people are renting these little miniature roadster thingies called "Go-Cars." You can also rent a Segway and get around town on that. Just another example of laziness and the trend away from exercise as recreation.