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?

How can you tell when you're full? I am not over-weight, but I tend to over-eat. How can I know when to stop?

1) Is it better to eat before or after exercising? I've recently started a fitness program and am not sure which way is the best.

2) Is it bad to eat before you have practice or a game in basketball?

Does banana have fat like avocados or olives? If so, what kind of fat does a banana have? Thanks.

I find that when I eat lunch I can feel myself instantly get tired as if a wave passes through me. My face gets a feeling of being sweaty and flushed. Coffee and copious amounts of water help counteract this. Also, it doesn't happen every day with every meal. Very small amounts of food don't cause this. It's as if I eat above a small threshold, then it happens. It makes it hard to work. A short nap would be perfect (but not possible). Is this something to be worried about?

1) I've started counting calories in order to lose weight, and I've lost ten pounds in six months, so I'm positive that counting calories works. Recently I've started to eat one big meal (about 1400 calories) a day. Is this healthy? Will I continue to lose weight?

2) During the day, I keep a strict paleo diet and end eating at 10PM and Begin eating at 12 PM the next day. Around 10:30 AM the next day, I do full a body weight training session and begin eating at 12 PM. Basically, I only drink water during my fast or keep calories to a five calorie maximum. After the fast, I eat whatever I want (paleo that is). I'm trying to get my body to use excess fat as energy, therefore causing me to lose body fat and gain muscle faster. I feel great and I have witnessed fast results, (increased strength and leanness) within a month and half of intermittent fasting. My question is do you think intermittent fasting is unsafe? Or just a new an effective way to see increased health?

I have heard that the main reason why diet drinks, like a diet soda, can be bad on a diet, is that it can spike insulin levels and then your body expects sugar that it does not get. I have taken to the habit of only occasionally having diet drinks with meals, so that any increase in insulin is actually met with food in my system. My question is whether or not this is a good/workable strategy, or whether a diet soda is a diet soda no matter when you drink it and is therefore always a bad idea. Thank you for your time.

Is it possible to lose all body fat? Should you eliminate all fat from your diet?