Does altitude affect calorie-burning? That is, if I do the exact same workout twice — once in New York City and once in Colorado — will I burn more calories at the high altitude? What things DO affect how many calories you burn in a workout?

I'm a college student and also a bodybuilder. I've become aware of very high protein intake amongst bodybuilders at my gym. I'm skeptical as to consuming as much protein (around 225 grams) a day like the bodybuilders at my gym do. Do bodybuilders need more protein? And if so, how much more?

I was anorexic for three years and I have been in recovery for two. At the moment, I am doing well. I have a healthy weight, I eat a balanced diet, I work out regularly though not excessively, and I feel good. However, I haven't had my period in about three years now. I had been told it would come back once I reached a healthy weight, but so far, no deal, even though I've been at this weight for over a year now.

Before I became anorexic, I did get my period regularly. I am 23 years old. I am taking a calcium supplement daily to prevent osteoporosis, but I would feel more comfortable if I did get my period again. What is going on? How worried should I be? Should I go see a doctor? What can I do about this?

I have recently learned that in order to burn fat as a fuel, your body requires carbohydrate. Up until this point I had been doing cardio training first thing in the morning on an empty stomach, as I had read that this is optimum for fat burning. However, now I have a small carbohydrate snack before I train in order to prevent my body using lean muscle tissue as a fuel. Today I have again read in another book that training on an empty stomach first thing in the morning burns the most fat. I am a little confused over the best thing to do! I train with weights twice a week and do cardio three times per week. I do want to maintain my lean muscle, but am looking to reduce my body fat.