People trying to lose weight always look for the most effective dietary tools to make the most of their effort, as weight loss can be a challenging undertaking. Searching online for diet tips can result in millions of controversial and unreliable advice and confuse rather than help dieters.1 This might also be the case online for low calorie sweeteners, the sweet-tasting ingredients that practically provide no calories and for which numerous randomised clinical trials, systematic reviews and meta-analyses have affirmed their effective role in weight loss and maintenance.2,3
A new study published in March 2016 in Nutrition and Diabetes4 provides important answers to online allegations that low calorie sweeteners (LCS) are related to higher obesity rates rather than helping people to manage their weight, based mostly on conflicting findings of some observational studies.5 The study by Drewnowski and Rehm showed that actually trying to lose or maintain body weight was one likely predictor of current LCS use. In other words, the study confirms what has been assumed for years, that people troubled by weight management turn to LCS as a strategy for weight control, rather than the other way around. As explained by the authors, this is a typical example of reverse causality.
Low calorie sweeteners use is related to the intent to lose and maintain body weight, the new study shows
The new study by Drewnowski and Rehm merged National Health and Nutrition Examination Survey (NHANES) dietary intake data with retrospective weight control histories, a rarely exploited resource within NHANES. The analyses used data from five NHANES cycles and included a representative US sample of 22.231 adults, for whom height and weight data as well as a valid 24h dietary recall were available.
Overall, the study findings confirm the main hypothesis that trying to lose or maintain body weight over a 12-month period was associated with higher LCS use, independent of body weight. Specifically, the analyses showed that individuals who tried to lose weight during the past year were 64% more likely to consume any type of LCS product after adjusting for age group, gender and race/ethnicity. Interestingly, the association between reported weight loss attempts and LCS use was observed for all types of LCS foods and drinks: for LCS beverages 72% more likely, for tabletop sweeteners 68% more likely and for LCS foods 93% more likely. Similar results were obtained with the ‘trying to not gain weight’ variable.
Furthermore, LCS use was much more common among individuals who experienced significant weight change in the preceding 10 years as compared with those who did not. For example, individuals who lost 50 lb (22,6kg) in the prior 10 years were 47% more likely to consume two or more types of LCS products, whereas those who gained 50?lb were 13% more likely to consume two or more types of LCS products as compared with individuals who gained 10?lb (4,5kg) over the prior 10 years. The finding that past weight fluctuations are a predictor of LCS use supports the hypothesis that people troubled by weight gain may turn to LCS as a strategy for weight control.
Low calorie sweeteners and obesity: A case of reverse causality?
Paradoxically, some observational studies have reported that regular LCS use may lead to obesity and diabetes5,6, although the data were not always consistent.7,8 In practice, there are particular difficulties in interpreting these types of studies, as their design cannot establish a cause and effect relationship and therefore reverse causality cannot be ruled out. Particularly in the case of low calorie sweeteners (LCS), it is assumed that people who are already overweight or obese, or at risk for diabetes are more likely to turn to LCS and consume foods and drinks containing them to manage their weight or their blood glucose levels.9
A few years ago, in April 2014, in his presentation at the International Sweeteners Association conference, Why Calories Count, which took place in Brussels, Professor Drewnowski suggested that “if low calorie sweetener users are more likely to be overweight, it is not because using sweeteners is causing their weight problems, it is because they are using sweeteners to lose or manage their weight. This is an example of reverse causality.”10
This new study by Drewnowski and Rehm provides the first analysis of the association between current LCS use, past weight loss/maintenance intent and 10-year weight history, which can help in examining the theory of reverse causality. A relation between LCS use and higher BMI and diabetes prevalence was observed, but those participants who reported trying to lose or not gain body weight during the previous 12 months were much more likely to use LCS too. Interestingly, the relation between weight loss/maintenance intent and current LCS use was not unique to obese individuals but held at all levels of BMI. That would suggest that LCS use was tied directly to dieting behaviors, regardless of whether the participants were overweight or obese. This new finding confirms that it is indeed a case of reverse causality, linking LCS use with trying to lose or maintain body weight. Similarly, people faced with the onset of type 2 diabetes may do the same and turn to LCS foods and drinks, not only in an effort to lose/maintain weight, but also to avoid consumption of added sugars and to better manage their blood glucose levels.
The benefits of low calorie sweeteners in weight management are well established
Systematic reviews of human trials confirm that LCS do not increase body weight or energy intake, and that the use of LCS can be a helpful tool in weight management.3 Recently, a meta-analyses published in International Journal of Obesity2 examined the results of over 100 human and animal studies regarding low calorie sweeteners and weight management and found that swapping low calorie sweeteners for sugar can lead to a decrease in energy intake and body weight, in both children and adults. Overall, the new publication by Drewnowski and Rehm shows that people use low calorie sweeteners in their effort to reduce dietary calories and manage more effectively their body weight, with a wealth of scientific evidence affirming that this strategy can be an effective dietary tool and LCS use can indeed help in weight loss
By providing sweetness without the calories, low calorie sweetened options can make a useful contribution to a healthy, calorie-controlled diet. You may find interesting information about the beneficial role of low calorie sweeteners in obesity management in ISA factsheet by clicking here.
You may access the original publication by Drewnowski and Rehm here.