Protein is one of the basic building blocks of the body so it is an essential part of your diet and can influence your strength but probably not your energy. Your muscles are built with protein and in fact protein is made up of 20 amino acids. Amino acids are the building blocks of protein and 9 are essential, they cannot be created and must be eaten meaning the other 11 amino acids can be created by our body.
Many times we here that you need to eat steak for energy but in actual fact as we learned earlier carbohydrates are the body's favored energy source. I always think of muscles as being made out of protein but really muscles are mostly water and protein so if you think about how people tend to diet they will cut out things like steak and carbohydrates so the body is not getting as much protein and carbohydrates as it needs to burn for energy so it will tend to burn protein and fat in equal parts to get energy. This is great for losing weight and good for losing fat but it is really bad to lose muscle. One of the ways to stop your body from burning muscle for energy is to do a fair amount of exercise, especially weight training to increase your muscle mass on a consistent basis.
So what kind of foods contain protein and how much do we need? Full proteins are found in steak chicken and fish and non-full proteins (those without all of the essential amino acids) are contained in lentils, beans, corn, peanuts. A can of Tuna has 20-25 grams of protein and if you look around you can probably get about 80 grams of protein a day comfortably. Some bodybuilders will eat 250-500 grams of protein a day but realistically if you have protein in a couple or three of your meals you are doing pretty good. One of the things to think about is that water is needed for your body to break down protein so if you are increasing your protein intake drink more water to gelp take the load off of your kidneys. Here are a couple links to protein resources here and here
Bill Nadraszky is a lifetime fitness and exercise junkie. Main website for more information is 30 days to fitness