I've read a lot of theories about how the body processes calories, burns fat, etc, and I'm not sure that anyone (especially an average person) can calculate this precisely. I don't know if scientists even have the tools to do this.
I can tell you that I kept a very careful food diary, and found that I can lose weight on more calories, when I limit carbs. I can also tell you that if I restrict carbs too much, exercise, even low intensity, is nearly impossible. I get dizzy, weak, and nauseous.
These are just personal observations from my own journals, but I think that's the best way for the average person to learn about what works for them. Document and evaluate. Exercise at your comfort level and note your results. Look for patterns, but don't jump to conclusions on too little data. It'll take months of journaling to really be confident that you've correctly identified a true pattern and not a coincidence.
I know there's a lot of theory being thrown around that for exercise to be effective, there are minimums of intensity and duration, but my theory is that even if true, you can only do what you can do. If only 30 minutes "count," but you can only do 20 - then do 20, because you'll never get to 30, until you've mastered 20.
I don't know if we ever have to truly understand "how" it all works, we just can do our best and through trial and error find out what works and is workable for us.
Last edited by kaplods; 06-07-2008 at 02:25 PM.