A study published in the American Journal of Clinical Nutrition found that eating 100 grams of sugar (less than the amount in 3 regular cans of soda) an significantly hamper the ability of your white blood cells to kill bacteria for up to 5 hours. So if you drink sodas all day long and eat lots of sugar and carbs, you are basically doing this to yourself all the time which can set you up to be sick not to mention what it does to your weight, your cholesterol and your diabetes risks.