evidence: There is no clear evidence that these sweeteners, at the levels typically consumed in human diets, cause cancer. Questions about artificial sweeteners and cancer risk arose when early studies showed that saccharin caused bladder cancer in lab animals, but studies in humans have shown no increased cancer risk. [...] Several types of sugars are found in foods and beverages. These sugars vary in their chemical structures, but once they are consumed, they all have similar metabolic effects in the body. All sugars in foods and beverages add to calorie intake, which can lead to obesity, so eating a lot of sugar can indirectly increase cancer risk. There is also evidence that a dietary pattern high in added sugars affects levels of insulin and related hormones in ways that may increase the risk of certain cancers. [...] Lab studies have shown that metabolism of glucose (the main sugar used as an energy source in the body) is faster in cancer cells than in normal cells. This fact is often misinterpreted by people, who assume (incorrectly) that sugars in foods and beverages directly "feed" cancer cells.