"Fruit Juice May Be Fueling Pudgy Preschoolers, Study Says" is the title of an article that appeared in the San Luis Obispo Tribune (February 27, 2005). This article describes a study that found that for 3- and 4-yearolds, drinking something sweet once or twice a day doubled the risk of being seriously overweight one year later. The authors of the study state Total energy may be a confounder if consumption of sweet drinks is a marker for other dietary factors associated with overweight (Pediatrics, November 2005). Give an example of a dietary factor that might be one of the potentially confounding variables the study authors are worried about.