training slower to race faster

I was reading some information on Mark Allen's website about training and racing. (He did win the Ironman World Championships a record 6 times, including when he was 37 years old).

The relevant text

"So he told me to go to the track, strap on the heart rate monitor, and keep my heart rate below 155 beats per minute. Maffetone told me that below this number that my body would be able to take in enough oxygen to burn fat as the main source of fuel for my muscle to move. I was going to develop my aerobic/fat burning system. What I discovered was a shock.

To keep my heart rate below 155 beats/minute, I had to slow my pace down to an 8:15 mile. That’s three minutes/mile SLOWER than I had been trying to hit in every single workout I did! My body just couldn’t utilize fat for fuel."

Now, I'm not sure I can run at lower than 148 BPM (my number given the formula), but I can bike at that pace.

"And after nearly a year of doing mostly aerobic training, which by the way was much more comfortable and less taxing than the anaerobic style that I was used to, my pace at 155 beats/minute had improved to a blistering 5:20 mile."

So his speed increased from 7.2mph to 11.2mph at an aerobic pace, which burns lots of fat and causes fewer injuries. Sign me up!

Along those lines, I've been thinking about a lot while eating lately -- keeping out the processed carbs. I won't repeat the huge amount of information about insulin and glycemic index, but here's what I'm thinking...

1- If I don't eat as many carbs, I won't be able to work out at that HARD intensity that burns carbs instead of fat (see above). This forces me into lots of long, slowish miles which leave me feeling good and ready for more.

2- If I don't waste my calories on junk with no nutritional value (bread, pasta, potatoes, fried food, candy, etc) then I get to eat far more meat and real vegetables. More protein and nutrients has gotta be good.

3- When I need to, I can eat a bunch of sugar for extra energy. I don't know how this will affect biking--I'm thinking/hoping it'll be some sort of "rocket fuel" for the really tough times-- like the epic Bunyon to Bobs last year.