Most answers arrive within three days.
Check the archive for previously answered questions. The site is nowhere near as substantive or interesting as the book, and that's too bad. Jennifer K. Nelson, MS, RD - Associate editor for nutrition who answers questions about food and nutrition. Includes commonly asked questions and has an archive available. Ask the Mayo Clinic Physician - Only medical questions of a more general nature are answered here, but there is a large archive of previous answers to search through.