One of the most common misconceptions endurance athletes have is that they need mass quantities of protein in their diet. The image that comes to mind for me is Rocky cracking a dozen raw eggs in the blender before heading out on his run. In reality, getting enough carbohydrates, and more specifically, good carbohydrates is much more of a challenge for most of us cyclists and triathletes.
Protein is required for muscle growth, repair and maintenance as well as the formation of hormones, enzymes, neurotransmitters and other components of the immune system. it is also required to produce hemoglobin in the blood. Most endurance athletes should aim for 15-20 percent of their Caloric intake from protein. In the U.S., most of us get far more, especially if we eat out a lot. Protein is found in high concentration in meats, fish, tofu and many beans and in lower concentrations in dairy products and nuts. While it is certainly possible to consume enough protein though plant based protein sources, animal based proteins are also good sources or iron and zinc, so vegetarian athletes should look for alternate sources of these minerals.
Since we burn protein as a fuel source in longer and more intense training sessions, some protein may be useful in the recovery process. However, it is not certain whether protein is really necessary in your post workout recovery drinks. The most important thing is to aim for 0.5-0.7 grams of carbohydrate (CHO) within 30 minutes of completion of the workout. This comes out to 65-90 grams for a 130 lb woman or 80-112 grams for a 160 lb man. Whether or not it the protein is necessary, it will not hurt if protein comprises up to 25% of the Calories in your recovery drink. Most marketed recovery drinks such as Hammer Perpetuem and Endurox have a 3-4:1 CHO:Protein ratio. These mixes are great if you are at away from home at a race, a Cadence class, or anywhere where you don't have access to your blender. My recommendation, though, is to eat real food whenever possible. So if you are at home or if you are close to a smoothie stand, have that instead. Not to mention, it tastes a lot better
If you are concerned about having enough protein in your recovery drink, be aware of the different types of protein contained in the supplements. Both Endurox and Hammer Recoverite contain whey protein, which is derived from milk. If you are lactose intolerant or you don't digest dairy products well after exercise, you may want to try a soy, egg or rice protein powder instead. Some people may find that casein protein absorbs well, though casein is also derived from milk.