Calorie Restriction Diet?

I just recently read about the calorie restriction
diet.

"In the western world, the caloric restriction therapy
became known with the description of the regimen of a
Venetian nobleman Luigi Cornaro (1464-1565) in his
book Discourse on the Sober Life .
His illness at the age of forty forced him to adopt
a strict lifestyle of sobriety from eating and wine
drinking.
Luigi has not only recovered from the illness, but
also has lived a long and productive healthy life.

The experiments of Clive McCay in 1935 showed that
when caloric intake was kept to about 30-40 percent
of what was normally eaten, the metabolic rate slowed
down and the aging process was delayed. This
translated into a decreased number of diseases and
increased survival rate in the experimental groups "

I was curious to know what the people here (who i
think are very well educated) think of the CR Diet as
it is called. For strictly health purposes as I think
if you are on it, you can kiss ANY athletic endeavor
goodbye.

Any opinions are GREATLY APPRECIATED! THANKS IN
ADVANCE!

I eat in the Zone, have been for about 5 years. It recommends lower calories than normal, not quite 30-40% though. I feel great, IMPROVED athletic performance for me compared to normal diets.