The sweeteners in artificially sweetened beverages (ASB) are potent stimulators of sweetness on the palate, yet contain no energy. This "mismatch" between sweetness and energy in ASB has raised concern about metabolism and health. This article provides a review of the recent literature on the effect of ASB on cardiometabolic risk factors and disease. Physiologic mechanisms are discussed, as well as epidemiologic studies. Prospective studies of ASB intake and the risk of obesity, diabetes, and cardiovascular disease have revealed inconsistent results. Higher-quality studies suggest either no effect of ASB or perhaps a protective effect through replacement of calorically dense alternatives. Although some studies have reported that ASB may increase risk, these observations appear to be an artifact of reverse causality. The limited experimental evidence does not support an effect of ASB on obesity or chronic disease. Indeed, experimental studies in humans suggest ASB may be effective for weight loss when replacing sugar-sweetened beverages.