A new systematic review published in the International Journal of Obesity looks at the totality of evidence investigating whether consuming low energy sweeteners (LES), such as aspartame, sucralose, or stevia, is a net benefit or detriment for weight control. In addition to providing some clarity on the answer, the review also provides some insight into how different kinds of evidence address such questions.
LES vs sugar or water
The question may at first seem obvious – if you consume a beverage sweetened with an LES instead of sugar you will be avoiding up to several hundred calories. Those calories add up quickly. Twelve ounces of cola with sugar has 138 calories, for example. These are foods that people generally consume on a daily basis, and so avoiding these unnecessary calories should reduce total energy intake and help reduce or maintain weight.
The human body, however, is a complex system, as is human psychology, and so we have to consider the law of unintended consequences. It is possible, for example, that when people drink a diet beverage they feel they have earned the right to consume more calories elsewhere. This phenomenon is called compensation, and there is evidence for this effect.