The Food and Drug Administration recently reaffirmed for the seventh time over four decades the safety of the popular sweetener aspartame, plainly stating, “Aspartame is one of the most studied food additives in the human food supply. … FDA scientists do not have safety concerns when Aspartame is used under approved conditions.”
There remains, however, confusion and chatter over the safety and efficacy of these ingredients. Among the most common questions is whether these sweeteners, found in many low- and no-calorie sweetened beverages such as diet sodas, help people safely manage weight.
The effectS of non-nutritive sWeetened beverages on appetITe during aCtive weigHt loss (SWITCH) trial, a new study from the University of Liverpool published in the International Journal of Obesity, provides some of the strongest evidence that low- and no-calorie sweetened beverages can be an effective tool to manage weight. The yearlong randomized controlled trial showed that drinking low- and no-calorie sweetened beverages is equivalent to or better than drinking water — the standard of care recommended by clinical practice guidelines and public health policy — for weight management.
This finding is significant in today’s marketplace, where consumers demand choice and a multitude of options — whether with the clothes that they wear, the entertainment that they stream or the foods that they eat — that fit into their lifestyles, habits and preferences. Nowhere is this issue more evident than on grocery store beverage shelves, where more and more consumers are looking for low- and zero-sugar options, such as diet teas and diet sodas. Today, more than 60 percent of beverages sold contain no sugars, thanks partly to the availability of low- and no-calorie sweetened drinks.
Randomized controlled trials like the SWITCH trial are considered the gold standard for nutrition research. They are typically used to inform clinical practice guidelines, public health policy and food safety regulations. Unlike observational studies that do not establish causation, randomized controlled trials assign participants randomly to either a “treatment” or “control” group, protecting against selection bias and allowing for the equal distribution between groups of prognostic factors or confounders that could influence the outcomes so that one can isolate the effect of the treatment.
The SWITCH trial included 262 randomly assigned participants split into two groups: one that consumed the standard of care water and the other that consumed low- and no-calorie sweetened beverages over 52 weeks. Participants were required to be at least 18 years old, overweight or obese, have no other major health issues and be regular drinkers of cold drinks, like soda or water.
The study consisted of three phases: a weight loss-phase with results assessed at 12 weeks, an assisted weight loss maintenance phase with results assessed at 52 weeks, and unassisted weight loss maintenance phase with results assessed at two years.
The last phase continues, but the first two phases at 12 weeks and 52 weeks demonstrated no significant differences in weight loss between water and low- and no-calorie sweetened beverages. People who drank these beverages lost slightly more weight than people who drank water.
These data reaffirm and build upon those from previously published systematic reviews and meta-analyses of randomized controlled trials. This work includes two systematic reviews and meta-analyses that I led for the update of the European Association for the Study of Diabetes clinical practice guidelines for nutrition therapy: one a 2023 evidence synthesis of the available large prospective cohort studies (the best designed observational studies) published in Diabetes Care, and the other a 2022 evidence synthesis of the available randomized controlled trials in the Journal of American Medical Association Network Open. It also supports the conclusions of a 2020 expert consensus statement. All concluded that low- and no-calorie sweetened beverages were viable alternatives to water for weight management.
The standard of care remains to drink water as often as possible. But these results are good news for people looking for other options to manage their weight or other health risks, including diabetes. Clinical practice guidelines and public health policy have moved away from a one-size-fits-all approach to dietary advice. It is recognized that there is evidence to support the health benefits of several approaches. The aim is to align the available evidence with the values, preferences, and health goals of the individual to help them find an approach that best works for them and so realize the health benefits. Low- and no-calorie sweetened beverages can provide such an approach by providing people with a safe, evidence-based alternative to water that can meet their taste, preferences and health goals.
Obesity and its downstream non-communicable diseases have emerged as the dominant public health concern. Major health authorities have called for reductions in free and added sugars, especially from sugar-sweetened beverages.
At the same time, these same authorities have called for more research on the effectiveness of low- and no-calorie sweetened drinks for weight management. This new trial responds to that call for action, confirming that low- and no-calorie sweeteners can be a safe and effective tool for people to manage their weight.