Ounce for ounce or calorie to calorie, almonds are the most nutritionally dense nut. The Dietary Guidelines for Americans 2005 encourage choosing nutritionally dense foods [foods that deliver the most nutrition possible out of the calories you eat]. A one-ounce, 160-calorie serving of almonds - about a handful - is an excellent source of vitamin E and magnesium, good sources of fiber. It also offers heart-healthy monounsaturated fat, protein, potassium, calcium, phosphorous and iron.