Low-energy substitutes for sugars and fats in the human diet: impact on nutritional regulation

Low-calorie substitutes for dietary sugars and fats are offered to the public as aids in the control of body weight. Their actual influence on food intake and energy regulation has been studied in many acute and longer-term studies. Artificial sweeteners are often presented as preloads, and their effects on subsequent intake are compared to those of sugars or nonsweet vehicles. Preloads are often liquid (drinks) or semisolid (yogurts) and presented as snacks, rather than parts of a meal. Under these conditions, partial or complete compensation for the missing energy is observed most often over the course of a few hours. However, increases in appetite have also been reported. Low-energy fat substitutes also apparently allow energy, but not nutrient (fat) compensation. Short-term, medium-term, and long-term behavioural responses to the use of low-energy substitutes can be different, mainly as a result of learning. Consequently, effects of their chronic use on body weight, body composition, nutritional balance, and various physical parameters are only partially predictable on the basis of present knowledge. The present article reviews recent contributions to this field and delineate open areas of research.