The role of low-calorie sweeteners in the prevention and management of overweight and obesity: evidence v. conjecture.

By virtue of reducing dietary energy density, low-calorie sweeteners (LCS) can be expected to decrease overall energy intake and thereby decrease body weight. Such effects will be limited by the amount of sugar replaced by LCS, and the dynamics of appetite and weight control (e.g., acute compensatory eating, and an increase in appetite and decrease in energy expenditure accompanying weight loss). Consistent with these predictions, short-term intervention studies show incomplete compensation for the consumption of LCS v. sugar, and longer-term intervention studies (from 4 weeks to 40 months duration) show small decreases in energy intake and body weight with LCS v. sugar. Despite this evidence, there are claims that LCS undermine weight management. Three claims are that: (1) LCS disrupt the learned control of energy intake (sweet taste confusion hypothesis); (2) exposure to sweetness increases desire for sweetness (sweet tooth hypothesis); (3) consumers might consciously overcompensate for 'calories saved' when they know they are consuming LCS (conscious overcompensation hypothesis). None of these claims stands up to close examination. In any case, the results of the intervention studies comparing LCS v. sugar indicate that the effect of energy dilution outweighs any tendency LCS might conceivably have to increase energy intake.