While there are no substitutes for genetic endowment and rigorous training in the achievement of optimal athletic performance, sound nutrition is critical for maximizing athletic potential. The importance of adequate dietary intake for athletes has been recognized for centuries, yet the modern field of sports nutrition is still very young and much is yet to be learned about using foods and dietary supplements for achieving optimal performance. Although controversies persist with regard to how diet may provide a winning edge, few researchers or dietitians would argue against the concept that an inadequate diet, deficient in energy or essential nutrients, will impair performance.