If you've ever treated yourself to a cup of ice cream in an attempt to beat the 3 p.m. slump, you likely caused more harm than good—and not just to your waistline. Not only does a cup of vanilla can have up to 10 grams of artery-clogging saturated fat and 28 grams of sugar but multiple studies have found that saturated fat and sugar-rich diets can diminish cognitive skills and verbal memory.