Low calorie sweeteners may satisfy the desire for sweetness, suggests new review

05 Dec 2017 --- Consumption of low-calorie sweeteners may have the advantage of satisfying desire for sweetness and controlling weight to some extent, according to a review of scientific literature examining their impact on weight control. The review, carried out by Professor Peter Rogers of the University of Bristol in the UK, negatively evaluates three common anti-sweetener arguments.

The review paper by Professor Rogers further evaluates three claims regarding the effect of low calorie sweeteners on energy intake and preference for sweetness: 1) the “sweet taste confusion” hypothesis, 2) the “sweet tooth” hypothesis and 3) the “conscious overcompensation” hypothesis.

Based on current evidence, the author concludes that there is little or no evidence in support of these claims in his review paper entitled “The role of low-calorie sweeteners in the prevention and management of overweight and obesity: evidence v. conjecture.”

Sweet taste confusion hypothesis
According to the “sweet taste confusion” theory, tested in animal studies, low calorie sweeteners would impair the body’s learned control of energy intake and weight regulation because there is a mismatch between sweet taste and calorie intake. The International Sweeteners Association (ISA) points out that there is no evidence supporting this hypothesis in humans.

The majority of animal studies do not confirm the theory that low-calorie sweeteners would disrupt the sweetness-energy association, a theory generated further to findings of a series of rat studies with saccharin by Swithers et al., the ISA notes. Indeed, the group reports that a recent study replicating the study design as in Swithers’ experiments concluded: “This result is in opposition to the findings of the Swithers group and others, but is consistent with the majority of animal and human research suggesting the effects of non-nutritive sweeteners are not more harmful than those of caloric sweeteners.”

The discrepancy in the results of studies of similar study design appears to be explained by a crucial difference in procedure, the ISA notes. It appears that a crucial piece of evidence used to support the claim that low-calorie sweeteners would disrupt the learned control of energy intake in Swithers et al. studies is based on false assumptions confounded by a procedural artefact, it adds.

Sweetness without calories and “sweet tooth”
The second argument against low-calorie sweeteners is the most prominent among policymakers claiming that the exposure to sweetness without calories may encourage a sweet tooth and therefore increased intake of sweet, energy-containing foods and beverages, ISA notes.

However, it points out that a large battery of evidence from both short- and longer-term human intervention studies does not support the “sweet tooth” hypothesis and rather indicates that the consumption of low-calorie sweeteners, studied mostly in the form of beverages, does not increase energy intake and may have to some extent the advantage of satisfying desire for sweetness when consumed shortly before or with a meal.

Conscious overcompensation when choosing calorie-reduced foods
There is also a question about human behavior and whether people may consciously overcompensate for “calories saved” when they know they are consuming low-calorie sweetened foods or beverages with fewer or no calories. The ISA reports that what is known to date from free-living intervention studies is that there is little or no conscious compensation when low calorie sweeteners are substituted for sugar as part of a calorie-counted weight loss diet.

On the other hand, the organization cites times when low-calorie sweetened foods are used as an excuse for indulgence, with the typical example being that of choosing a diet soda while eating a whole pizza. Full compensation may occur, the ISA concedes, but no one can predict if the same person would eat one less piece of pizza if a sugar-sweetened soda had instead been chosen.

In any case, the ISA points out that this certainly has to do with consumers’ nutrition education and cites the author’s conclusion that “taken together, there is little evidence for conscious compensation for low-calorie sweeteners’ consumption.”

Facts versus claims
Examining what is known to date about sweetness without calories and about the effect of low calorie sweeteners on energy intake and body weight, Professor Rogers concludes in the review that there is little or no evidence in support of claims suggesting that low-calorie sweeteners would undermine body weight regulation.

“At the very least, the reduced energy content of low calorie sweetened foods and beverages is not fully compensated, thus helping us to cut our daily calories down,” the ISA says. “And of course, reducing calorie intake and managing our overall energy balance (calories in – calories out) are key elements of successful weight loss. This is probably why longer-term intervention studies consistently confirm that the consumption of low calorie sweeteners in place of sugar in the diet can help in modest weight loss.”

Low-calorie sweeteners are not a “silver bullet” in weight loss and should not be seen as one, the ISA points out, but it adds that including low-calorie sweetened foods and drinks in the diet can be among the many strategies used in weight management efforts to help keep the enjoyment of sweet-tasting foods with fewer or no calories.

References
Miller PE & Perez V. Low-calories sweeteners and body weight and composition: a meta-analysis of randomized controlled trials and prospective cohort studies. Am J Clin Nutr 2014;100:765–777.
Rogers PJ, Hogenkamp PS, de Graaf C et al. 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. Int J Obes 2016;40:381–394.
Rogers PJ. The role of low-calorie sweeteners in the prevention and management of overweight and obesity: evidence v. conjecture. Proceedings of the Nutrition Society 2017 Nov 23:1-9