 Erythritol, the too-good-to-be-true non-toxic, low-calorie, tooth-friendly sweetener that may even act as an antioxidant, what's the catch? Well, there are three ways that all non-chloric sweeteners could theoretically be harmful independent of their specific chemistry. Over the years, several large-scale prospective cohort studies found a positive correlation between artificial sweetener use and weight gain, meaning the people that drank the most diet soda, for example, gained the most weight. Another most common explanation for this counter-intuitive finding is what's called reverse causation. And people aren't fat because they drink diet soda. They drink diet soda because they're fat. But there are at least three other, less benign, alternative explanations. The first is called overcompensation for expected caloric reduction. If you covertly switch someone's soda for diet soda without them knowing it, their caloric intake drops. Obviously, they're not drinking all that sugar anymore. But what if you tell them what you did? People who knowingly are consuming artificially artificial sweeteners may actually end up eating more calories. Why? Because they're like, hey, I'm drinking diet soda so I can have two pieces of cake. In this study, they gave people an artificially sweetened cereal for breakfast, but only told half of the group what they did. As you can see, when it came to lunchtime, the aspartame-informed group ate significantly more than the aspartame-naive group that didn't know any different.