Back in the 1920s, the H.B. Reese Candy Company started producing a peanut butter candy wrapped in Hershey's milk chocolate. This product was originally known simply as a peanut butter cup. It was later was renamed to become the Reese's Peanut Butter Cups we know today. Although peanut butter cups are a candy and are high in fat, the treat is also a good source of protein.

One serving of Reese's Peanut Butter Cups consists of a package of two cups. There are 42 grams or 1.6 ounces of candy in two peanut butter cups.

There are 210 calories in a package of Reese's Peanut Butter Cups, or 105 calories per cup. Just over half of the calories, 110, come from fat, so Reese's Peanut Butter Cups are a relatively high-fat food.

There are 13g of fat in a single serving of Reese's Peanut Butter Cups. This is 20 percent of the daily value for fat. Saturated fat makes up 4.5g, and this is 23 percent of the daily value for this type of fat. There are more calories per gram of fat than per gram of protein or carbohydrate, so the high fat contributes to the high calorie count of Reese's Peanut Butter Cups.

A pair of peanut butter cups contains 24g of carbohydrates. Fiber makes up 1g, and 21g of carbohydrates are simple sugars.

Though Reese's Peanut Butter Cups are high in calories and fat, they are an excellent source of protein. A serving provides 5g of protein, which is 10 percent of the recommended daily value.

A serving of Reese's Peanut Butter Cups contain 150mg of sodium or 6 percent of the daily allowance for sodium. A pair of peanut butter cups contains less than 5mg of cholesterol. Reese's Peanut Butter Cups do not have any vitamin C, but a serving contains 2 percent of the daily value for calcium and 4 percent of the daily value for iron.