An occasional anything will not kill you. You don't have to be perfect all the time! My wellness protocol stresses that. Our bodies are built to withstand bad food every now and then. It is only when we make these offenders a regular part of our diets that it becomes a problem. I don't know if corn syrup is directly metabolised into fat (sounds a little weird), but it and ANY sweetener/simple carb will spike your insulin levels and cause all the blood Sugar related problems like weight gain, diabetes, inflammation and mood swings. It is now believed that inflammation is at the heart of most disease as well as premature aging. You just have to ask yourself, "do I want this pop so bad that I'm willing to accelerate my aging process and risk weight gain just to taste it?" Once in a while, the answer might be a resounding YES! But, hopefully it will be no and you will move on to a more health promoting drink.