Morning Pick-Me-Up: Coffee or Diet Soda?

Answer: Compared to plain black coffee, a diet soda may actually be a slightly better choice for morning, says Elizabeth Somer, RD, author of 10 Habits That Mess Up a Woman's Diet (McGraw-Hill, 2006). "Though coffee and black tea both provide antioxidants, they also contain tannins, which can interfere with the absorption of iron from typical breakfast foods like fortified cereals and oatmeal." If you're just looking for a pick-me-up, coffee, tea, and diet soda will all do the trick. "The more important choice is what you eat for breakfast," says Milton Stokes, RD, a spokesperson for the American Dietetic Association. "If it's just a calorie-free caffeinated beverage, you're setting yourself up for a mid-morning energy slump."

Originally published in Fitness magazine, February 2006.