The September 2010 Fitness Rx issue has an excellent 3-page scientific article about fat loss. It's called, "The Scientific Approach to Ultimate Fat Loss: Burn Body Fat As Fuel". Let me save you the trouble of trying to sift through all of the scientific verbage that was even tough for me to get through (and I made an A in that class). I'm going to concisely sum up the main points of the article.
1. To burn maximum fat during exercise, use interval training. This is where you mix in bursts of high intensity exercises with periods of moderate intensity exercises. As an example, if you were on a treadmill, you might speed walk up hill at 3.5 mph and 5% incline for 10 minutes followed by 5 minutes of jogging at 6.0 mph and 5% incline, then continue those intervals for 3 cycles. This alternates you between moderate and high intensity exercise.
2. Time your exercise for 4 to 6 hours after a meal if you're not planning to work out before breakfast. This allows blood insulin levels to level off and puts your body in the best position to burn fat during exercise, especially in the type of exercise described above.
3. More on timing: The best time to exercise is first thing in the morning, before eating breakfast. I explained this point in my previous post that can be found at: http://leanbodypro.blogspot.com/2010/08/research-on-fat-loss-exercise-in.html.
So, there you have it. Most people drown in the science. Even I think it's boring sometimes. You don't want to read about mitochondria, fatty acids, and adipocytes. Just give it to me straight. Well, I did. Interval training and exercise on an empty stomach.