You'll be less likely to die of cancer or heart disease if you get less of your protein from red meat and more from plant foods, say researchers at the Harvard School of Public Health. This includes nuts like peanuts or pistachios. Peanuts and pistachios are cholesterol-free and rich in heart-healthy fats. Use them as a quick snack or as an unusual breading for poultry, or add them to salads and noodle dishes. Avoid oil-roasted and salted nuts that are high in sodium; also, be sure to keep your portion size under control. A single serving of nuts is only about 0.5 ounce.

Most of the calories in a serving of either peanuts or pistachios is supplied by fat. Peanuts have 83 calories in each 0.5 ounce, with 63 -- or about 72 percent of the total -- contributed by fat. Pistachios have 81 calories, though only 66 percent are from fat. Both contain a similar amount of saturated fat, at around 0.8 or 0.9 gram per serving. In addition, both contain over 3 grams of monounsaturated fats in 0.5 ounce. A diet rich in monounsaturated fats may lower your risk of stroke, heart disease and high blood cholesterol.

Nuts like peanuts and pistachios aren't good sources of carbohydrates. A half ounce of pistachios has just 4.1 grams of carbohydrates, while the same amount of peanuts has approximately 3 grams. Over 1 gram of the carbohydrate total in 0.5 ounce of both pistachios and peanuts is supplied by dietary fiber. Nuts are a source of both soluble and insoluble fiber. Eating plenty of both types of fiber can help you avoid diabetes, high blood cholesterol and digestive disorders like hemorrhoids.

Peanuts contain 3.4 grams of protein in every 0.5-ounce serving, while pistachios have about 3 grams in each serving. The Centers for Disease Control and Prevention says that healthy adult women should have about 46 grams of protein daily, while children between 4 and 18 years old need 19 to 52 grams each day, depending on their age, activity level and gender. A serving of pistachios or peanuts would fulfill about 7 percent of a woman's daily protein requirement; for an elementary school-aged child, it would fulfill almost 10 percent of a day's protein needs.

Peanuts and pistachios are both a source of B vitamins such as niacin, pantothenic acid, vitamin B-6, riboflavin and folate, though they contain slightly different concentrations of each. Peanuts have more niacin, with 1.9 milligrams in every 0.5-ounce serving, or 13 percent of a woman's recommended daily allowance. Pistachios are a better source of vitamin B-6: Each 0.5-ounce serving has 12 percent of the RDA for a woman.

Peanuts are rich in manganese, a mineral that helps regulate your blood sugar and aids in the production of sex hormones. A 0.5-ounce serving of peanuts fulfills 17 percent of your requirement of manganese as an adult woman. Pistachios also contain manganese, but are an especially good way for you to increase your copper intake. Adults need 900 micrograms of copper each day, and pistachios contain 183 micrograms in every 0.5 ounce. Pistachios and peanuts also contain iron, magnesium and potassium.