Protein is one of the four main areas of nutrition, the others being carbohydrates, fats and micronutrients.
To understand protein, it is helpful to know some basic nutritional science. Protein is made up of amino acids ; there are 22 normal amino acids and 8 of them are called 'essential' because they have to be eaten as the body cannot produce them from other foods . A food can be described as 'complete' if it contains a balance of the essential amino acids. Complete proteins are generally from animal sources - dairy and meat. However, you don't need to get all the amino acids from the same food to get a complete protein. Simply having beans and cereals in the diet will create the balance needed. (They don't need to be eaten in the same meal )
The human body as no 'store' of protein other than your muscles. There is some interesting research that indicates that having amino acids available as quickly as possible after training will improve muscle synthesis (and therefore recovery). The ideal approach seems to be to take raw amino acids, either before or after training . as they are available more quickly than protein, but this is more expensive than protein. Whey protein is more easily digested (two hours) than other forms of protein, so this is the next best approach. Taking protein before exercise is best, but I for one can't tolerate much protein when running. Taking protein with fast carbohydrate (high Glycemic Index) can create an insulin spike that also helps muscle synthesis. So taking some Whey protein in Gatorade immediately after running should help recovery and muscle building. [5, 6]
What about sports drinks/gels that contain Protein? The evidence for protein consumption during exercise improving performance is somewhat mixed . My suggestion would be to try it and see how you get on. You could use the commercial carbohydrate/protein drinks/gels, or you could make your own drink by adding protein powder to your current drink. The latter would give you the option of using a higher quality protein, or even an amino acid combination.
There is a lot of debate over the correct level of protein intake, especially for endurance athletes. However, my overall research indicates that 1.3-1.5 grams per kilogram body weight per day is about right for serious runners.
There is also debate over taking protein before sleeping. Most repair and recovery occurs at night, so having an adequate supply of protein seems like a good idea, but there are suggestions that it may interfere with sleep. There is also indications that while the essential amino acid tryptophan is vital for sleep, many sources of protein lack sufficient quantities . Personally, I find that a scoop of protein in a glass of milk seems to help me sleep.
I take Optimum Nutrition's Gold Standard 100% Whey, as it dissolves easily, is reasonably priced and seems to be good quality. The vanilla flavor tastes great mixed with Gatorade, or with milk and cocoa powder.
http://www.bulknutrition.com/p62_100__Whey_Protein_-_Gold_Standard_Optimum_Nutrition.html. They also have bulk amino acids for instance - http://www.bulknutrition.com/?products_id=1511
Amino Acids http://en.wikipedia.org/wiki/Amino_acid
Complete Protein http://en.wikipedia.org/wiki/Complete_protein
Protein Combining http://en.wikipedia.org/wiki/Protein_combining
protein metabolism http://www.pponline.co.uk/encyc/protein-metabolism.htm
Strength Training Diet http://www.pponline.co.uk/encyc/strength-training-diet.htm
Protein: how much do runners need? http://faculty.washington.edu/crowther/Misc/RBC/protein.shtml
Runner's World - eat more protein http://www.runnersworld.com/article/0,7120,s6-242-300--12554-0,00.html
Energy drink: do protein shakes improve performance? http://www.pponline.co.uk/encyc/energy-drink-do-protein-shakes-improve-performance-40878
waking up to the performance of sleep http://www.pponline.co.uk/encyc/sleep-loss-making-sure-it-doesnt-affect-your-training
Branched chain amino acids prevent muscle protein breakdown but they don't boost performance http://www.pponline.co.uk/encyc/0391.htm