"3) Aerobic training makes your body an efficient fat-burning machine. True, but this isn't a desirable response. Yes, aerobic training does demand work from the muscles, but not as much as other activities, and it doesn't require the muscle tissue to last, either. Because the only tissue that burns fat in the body is muscle, aerobics are ineffective at building and maintaining your body's fat-burning tools."
Not at all. It's a very desireable response. Aerobics increases the number of mitochondrie, the associated enzyns and about 5 other changes (or "fat burning tools") in the muscles/body to improve the transfer of fat too and the oxidation of fat in the muscles.
Note too that the only tissues that burns carbs is also the muscles except that which fuels the brain. Alcohol and protein are also burned in the muscles.
If you don't optimize your fat burning metabolism (lipolysis) you won't have any endurance. The first phase of any racer's program is to maximize his fat burning ability (long slow rides) which pays off especialy at higher heart rates.
A typical 186 pound man with 15% body fat has about 106,000 calories of stored fat and only 2000 calories of stored carbohydrate. You wouldn't last one stage of the Tour with out maximizing your fat buring.
Before the 2000 carb calories get very low, the brain will start shutting down the body to preserve itself. We call that bonking. In the extreme, the brain will cannobolize muscle protein to convert to carbs damaging the muscles in the process. It's absolutely imperitive to burn as much fat as possible if you are into high intensity endurance activities.
Before I knew about such things, I bonked very badly on a mountainous road ride. I had just come up from N Florida and had a friendly race for miles. I felt in no pain afterwards. But shortly after supper, I lost all my periphrial vision. It was like looking at the world through soda straws. I called my optomatrist at home back in Florida. He said either you've had a massive stroke which was unlikely as I was still concious or I had run too low on carbs. I've avoided that problem with better fitness and better nutrition before, during and after the ride.
From Sport Nutrition for Health and Performance (2nd edition):
Maximum fat oxidation occurs at 59 to 65% VO2 max for trained and 47 to 52% for untrained. "This has an advantage for both weight maintenance and weight loss because the trained individual, who can optimally burn fat at higher VO2max, will burn more calories than the sedentary individual in a given amount of time exercising. Finally, exercise training also spares endogenous carbohydrates stores that may be needed for prolonged high-intensity events, so you can work harder longer."
Of course I also do weight training to build and maintain muscle mass. Carbs are necessary for that as well. So is adequate protein.
http://www.ajcn.org/cgi/reprint/81/6/1442
"Briefly, at 3 mo, the protein group had significantly
greater increases in FFM and decreases in body fat than did the
carbohydrate group. However, by 6 mo, these differences were
no longer evident. Bench-press strength increased significantly
more in the protein group than in the carbohydrate group (51%
and 35%, respectively) from baseline to 6 mo."
Al