ISA statement in response to Tey et al study
Contrary to the strong body of evidence showing that low calorie sweeteners lead to reduced energy intake and weight loss1, a new study published in International Journal of Obesity2 suggests that there was no difference in total daily energy intake following the consumption of low calorie sweetened drinks and sugar-sweetened beverages.
The study by Tey et al cannot provide evidence to the claims of a Press Release3 suggesting that “The energy ‘saved’ from replacing sugar with non-nutritive sweetener was fully compensated for at subsequent meals”. A large number of randomised clinical trials published over the last three decades, conducted in many different groups of people, have shown that when consuming low calorie sweeteners preloads, participants do not compensate by eating more at either their lunch or dinner meal and report similar levels of satiety compared to when they consume the higher calorie sucrose preload. 4, 5, 6
Importantly, the limitations of this study including the short-term nature of the trial (one day) have to be taken into serious consideration in interpreting the results of the study. The authors themselves note that “when the results are taken together, the evidence seems to suggest that the use of non-nutritive sweetener does not lead to overconsumption” and that “this cannot be confirmed in the current study due to the acute nature of the trial.” Furthermore, another important limitation of the study is the self-reported dietary data for subsequent meals after participants left the study site (after lunch). Interestingly, and in line with other studies, only partial energy compensation (22-32%) was observed at lunch time (the only meal that volunteers consumed under supervision at the study site), which actually shows that replacing sugar with low calorie sweeteners led to reduced energy intake at the following meal. Regarding the study finding that volunteers compensated the ‘saved’ energy by the end of the test day, this cannot be proved by this study outcomes as dietary intake was self-reported at home after lunch time, which is an important limitation of this study.
The beneficial role of low calorie sweeteners use in reducing calorie intake and weight management was affirmed clearly in the recent systematic review and meta-analysis by Rogers et al1, which analysed the outcomes of 56 short-term trials and nine long-term studies in relation to energy intake as an end-point, and concluded that the findings of the available literature are consistent that the use of low calorie sweeteners lead to reduced energy intake and weight loss. Specifically, short-term studies show that consumption of low calorie sweeteners in place of sugars is consistently found to reduce short-term energy intake, in contrast to what Tey et al suggest. Also, contrary to the concern that low calorie sweeteners might increase intake acutely through stimulation of subsequent energy intake by sweetness or via other mechanisms7, energy intake did not differ for low calorie sweeteners versus water or versus unsweetened products. Furthermore, in all cases of longer randomised controlled trials (RCTs), the use of low calorie sweeteners led to a reduction in energy intake. Notably, there was no example of a sustained exposure intervention trial where low calorie sweeteners use led to a relative increase in mean energy intake or body weight.
In light of the obesity epidemic, low calorie sweeteners can play an important role in helping people reduce their sugars and calorie intake. Foods and beverages sweetened with low calorie sweeteners can provide people with a wide choice of sweet-tasting options with low or no calories that can help in weight loss and maintenance.