EVEN 500 YEARS AGO people had some inkling that what we eat affects our well-being. “A good coke is halfe a physycyon,” wrote Andrew Boorde in 1547 in Breviary of Health. Head chefs, or majordomos, seasoned their dishes with early ideas about diet and nutrition that still influence meals today, as Rachel Laudan explains in her article, “Birth of the Modern Diet,” starting on page 4. We have been grappling with what food means for health ever since. In recent years, modern science has come to the table, gathering the many insights you’ll find in this special issue.

Obviously, we need a certain minimum diet to survive. But overabundance is also a problem, as we learn in banner headline after headline about the detrimental effects on the cardiovascular system and other areas of the body. But is that so? In his article on page 76, W. Wayt Gibbs explores the question, “Obesity: An Overblown Epidemic?”

Also in the news a lot lately is the idea that cutting calories may prolong youthful vigor into old age. “Calorie Restriction and Aging,” by Richard Weindruch, explains, beginning on page 54, how animals that consume one-third fewer calories in studies display greater vitality than animals fed a normal diet. If the regimen sounds punishing, don’t despair. “The Serious Search for an Antiaging Pill,” by Mark A. Lane, Donald K. Ingram and George S. Roth, offers hope for finding a drug that mimics the effects of calorie restriction. Turn to page 62.

Amounts are one factor, but what we eat is also a critical influence on our abilities to stay strong and active into the twilight years. Science has learned much since the “four food groups” that my mother nagged me about as a child. Starting on page 12, “Rebuilding the Food Pyramid,” by Walter C. Willett and Meir J. Stampfer, reviews the latest research on creating a proper diet.

Last, as the holiday season is upon us, let us make a toast to another source of vital spirits. In “Drink to Your Health?” Arthur L. Klatsky tells us how small to moderate amounts of alcohol can lend cardiovascular benefits. The article begins on page 22. Cheers.

Executive Editor Scientific American editors@sciam.com