This article is from the Running FAQ, by Ozzie Gontang with numerous contributions by others.
Basically, what all this means is that good nutrition for the *runner* is
not hard to come by once we understand our body's nutrient and energy
requirements. If a balanced diet meets the RDA's for protein, vitamins and
minerals as well as carbohydrate and fat intake for energy then everything
should be OK nutritionally. It should be remembered that the problems
associated with nutrient deficiencies take a long time to occur. Because of
this it is not necessary to eat "right" at every meal which explains why
weekend racing junkets can be quite successful on a diet of tortilla chips
and soft drinks. However, bear in mind that over time, the body's
nutritional demands must be satisfied. To play it safe many *runners* take
a daily multivitamin and mineral supplement tablet which has no adverse
affects and something I personally recommend. Mega vitamin doses(levels
five times or more of the RDA) have not been proven to be beneficial and
may cause some toxicity problems.