I know that plants (besides soy) are considered "incomplete" protein sources, because they don't contain all of the essential amino acids. However, why is it that the nutrition facts of many grains and vegetables say they have protein? For example — a serving of pasta has seven grams of protein, corn has twp grams, and chickpeas have six grams. Is this considered "incomplete" or "complete" protein, and how can you know how much complete protein you are eating when you mix, for example, a serving of corn, and beans? I think average people should eat 50 to 60 grams of protein a day, but how can you ever know how much you are really eating if you are mixing incomplete proteins that together contribute to your day's protein requirement?

1) When I do a 3-mile or 5-mile run, I run for time and try to finish with nothing in the tank. The closer I get to the end, the more I push myself, because I know I don't need to sustain the effort much longer. When I stop running, I suddenly get very light-headed and dizzy. It never happens while I'm running. I walk briskly while I'm warming down, but that doesn't prevent it. Why does this happen? Is it dangerous?

2)  Sometimes after jogging a while, or cycling a great distance, my head begins to spin and I feel as if I'm going to pass out. Is it normal to have feelings like these, and if so, how intense should these feelings be?