A team of NIH scientists discovered that racking up 100 extra calories a day—by burning less and/or eating more—over three years adds ten pounds to the average person. That same NIH team recently found that obesity began to skyrocket in 1978, when Americans added an average of 218 extra calories per day (mostly because we snacked more and moved less). That figure alone—the equivalent of 13 tortilla chips—they believe, is enough to explain the boom in obesity.
