When I had gastric bypass surgery last year, I was introduced to protein drinks. You see, as a gastric bypass patient, I need a minimum of 60 grams of protein a day, and it's difficult to get that much protein from the food I eat because I can only eat limited amounts at a time.

GNC has come a long way from its roots as a tiny health store founded in Pittsburgh, Pennsylvania, in 1935. What was once a single storefront specializing in yogurt and "healthy sandwiches" has blossomed tremendously over the last seven decades, and GNC now operates more than 4,800 locations across the United States. In addition to carrying a plethora of products from brands such as Optimum Nutrition and BSN, GNC stores also carry their own line of premium products, known as "Pro Performance."