Credit: Riou/Getty

One ounce of nuts – roughly 24 almonds or 48 shelled pistachios – delivers approximately 6 grams of protein, along with heart-healthy monounsaturated fat. But because nuts are an incomplete protein, with fewer essential amino acids than all high-protein foods, including beans, they nab our lowest protein score. Also, nuts have more calories per ounce – approximately 150 – while those roasted in oil can easily surpass the 200-calorie mark.

Choose a handful of shelled walnuts (about 1/4 cup) for 4 grams of protein, 2 grams of fiber, and 2,500 milligrams of alpha-linolenic acid, shown to reduce heart disease risk. Recent studies have also found that walnuts lower bad LDL cholesterol. Protein power: Fair.