"Studies show that you can lower your risk of cardiovascular disease by 15% to 50% if you eat a handful of nuts five times a week. If you found a pill that did the same thing, you'd make a fortune." Of course, chowing down on a huge tub of walnuts can be counterproductive, so as always, watch your intake. A handful of dry, roasted, unsalted walnuts -- about 14 walnut halves -- has about 150 calories, and is enough to yield "superfood" benefits.