It doesn't take a genius to figure out eating potato chips will cause you to pack on the pounds.

Or maybe it does.

Researchers at Harvard have found that eating the salty snacks will result in people gaining more weight over several years than they would eating other foods. The study's findings appear in the New England Journal of Medicine.

The scientists, who examined the eating habits of more than 120,000 people, looked at how big their bellies would get when adding one additional daily serving of food was included in someone's diet over a four-year stretch. The results? Scarfing down potatoes means you're looking at tacking on 1.28 pounds, while French fries adds a belt-busting 3.35 pounds.

Munching on chips each day for 20 years adds 1.69 pounds every four years. Conversely, enjoying yogurt has the opposite effect -- people dropped .82 pounds every four years.

Frank Hu, one of the study's lead researchers, thumbed through his dictionary of the obvious when he said, “These findings underscore the importance of making wise food choices in preventing weight gain and obesity.  The idea that there are no ‘good’ or ‘bad’ foods is a myth that needs to be debunked.”

Perhaps not surprisingly, Frito-Lay had no comment on the study. Maybe the spokesman was too out-of-shape to run over to the phone when it rang.

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