Energy density of foods, as opposed to their sugar or fat content, is said to be a key determinant of energy intakes. Recent laboratory studies have shown that, under ad lib conditions, subjects consume a constant weight or volume of food, so that their energy intakes depend on the energy density of the diet. Because low energy-density foods provide fewer calories per eating bout, they should-in theory-lead to reduced energy intakes and therefore weight loss. However, there is some question whether energy-dilute foods are as palatable as the more energy-dense foods. Generally high energy density equals high palatability and vice versa. Intense sweeteners represent an exception to the rule, since they maintain sweetness while reducing energy density. While many studies have explored the effects of intense sweeteners on short-term regulation of food intake, fewer studies have addressed the effectiveness of intense sweeteners in reducing energy density for weight control. Issues of energy density, palatability, and satiety, as applied to intense sweeteners are the topic of this review.