Snacking, not portion size, largely driving U.S. overeating

Over the past several decades Americans have steadily gotten fatter. Although our increasingly sedentary lifestyles are partly to blame, a big reason for our national weight gain is that we're simply eating more.

In the mid-2000s, government surveys show, the average American adult ate about 2,375 calories per day, nearly one-third more than he (or she) did in the late 1970s. What accounts for all those added calories?  More....Yahoo health