Let's start with Coke's longtime rival — a can of Pepsi lends a little more caffeine at 38.9 milligrams. Alternatively, Dr. Pepper has 42.6 milligrams of caffeine. For even more energy, a Diet ...
but I did notice that my stomach felt a little off after I drank about a quarter of my protein Diet Coke. Not bad, just…unsettled. Maybe it was the protein, maybe it was the caffeine ...