Diet foods do more harm the good. Whether it is a “diet” beverage or a box meal with a “low fat” label, there is nothing real about these foods; they are chemically enhanced with additives and processed with refined flours and sugars. Just Say No. Aspartame is the most common artificial sweetener in diet foods. According to the European Food Safety Authority, aspartame is responsible for causing a wide range of illnesses including cancer, birth defects, and heart problems. Skip the “diet” frankenfoods and go organic instead.