There's caffeine free Diet Coke, Diet Pepsi and most major supermarket chains have their own version. The store brands are usually also sodium free, and have less aspartame. The sodium seems to make a difference for me, not the caffeine. I sleep better without the caffeine but I have more energy with it. I have been drinking lots of it since I started Atkins. In fact, I drink it instead of water, but that's just me!