Sorry, Popeye, but no. Although spinach contains nutrients (such as iron and magnesium) that help your muscles contract correctly, as well as carbohydrates for energy, there’s nothing that will make a noticeable difference in the amount you can bench press, says Pamela Peeke, M.D., an assistant professor of medicine at the University of Maryland, in College Park, and author of the book Body for Life for Women (Rodale, $27, available on www.barnesandnoble.com).

Also a myth is the idea that eating extra protein makes you stronger, says Marla Richmond, an exercise physiologist and spokesperson for the American Council on Exercise. “Protein provides materials to build and maintain muscle and other body tissues, but eating more protein than what your body needs doesn’t build more muscle, any more than eating fingernails will make your nails grow.”