Low-calorie sweeteners such as saccharin, aspartame, sucralose and stevia provide sweet taste with few or zero calories. Therefore, when consumed in place of sugar, low-calorie sweeteners can be expected to reduce overall calorie intake and help with weight control. Concern, however, has been raised that they might have the opposite effect, for example because they may confuse the relationship between sweet taste and calories in our diet, or because exposure to sweetness increases desire for sweetness and consequently increases intake of sugary foods. Very often research findings are cited selectively (‘cherry-picked’) to support one view or another. In response to this and the resulting uncertainty that prevails about the usefulness of low-calorie sweeteners for weight management we carried out a systematic review of all of the relevant evidence (Rogers et al., 2015). This included studies in animals as well as humans.

The weight of evidence was clearly in favour of low-calorie sweeteners consumption. In particular, we found that a variety of randomised, controlled intervention trials showed consistently that low-calorie sweeteners versus sugar consumption reduces energy intake and body weight, with no effect or even reduced body weight compared with consumption of water. These types of studies provide the strongest form of evidence – superior to animal and observational studies. The majority of animal studies we identified found that exposure to low-calorie sweeteners either decreased or had no effect on weight, although consumption of low-calorie sweeteners in most of the animal studies was not representative of their consumption in the human diet.

The finding that low-calorie sweeteners do not increase energy intake when compared with water is important. Perhaps in some contexts consuming a sweet, low-calorie sweet beverage might even reduce energy intake – for example by decreasing the desire to finish the meal with a sweet dessert. We are currently investigating this, and also the possibility that consuming low-calorie beverages causes consumers to relax restraint over aspects of their diet.

Reference

• PJ Rogers, PS Hogenkamp, C de Graaf, S Higgs, A Lluch, AR Ness, C Penfold, R Perry, P Putz, MR Yeomans, DJ Mela. 2015. Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies. International Journal of Obesity. Click here to view