An Overview of Reviews on the Association of Low Calorie Sweetener Consumption With Body Weight and Adiposity.

Background: Numerous systematic reviews (SR) and meta-analyses (MA) on low calorie sweeteners (LCS) have been published in recent years, concluding that LCS have beneficial, neutral, or detrimental effects on various health outcomes, depending on the review.

Objectives: The objective of this overview of reviews was to determine how the methodologies of SR investigating the association between LCS consumption and body weight (BW) influence their findings and whether MA results can provide a consistent estimated effect.

Methods: Systematic searches of PubMed, Scopus, and Cochrane Library were conducted in November 2022 to identify SR of randomized controlled trials (RCT) or non-randomized studies (NRS) investigating the association between LCS consumption and BW. The methods, MA results, and conclusions were extracted from each eligible SR.

Results: Of the 985 search results, 20 SR evaluated the association between LCS and BW, drawing from publications of 75 RCT, 42 prospective cohort studies, and 10 cross-sectional studies. There was a considerable lack of overlap of studies included within each SR attributed, in part, to the inclusion of studies based on design; thus, each SR synthesized results from distinctly different studies. Evidence synthesis methods were heterogeneous and often opaque, making it difficult to determine why results from certain studies were excluded or why disparate results were observed between SR.

Conclusions: SR investigating the effect of LCS on BW implement different methodologies to answer allegedly the same question, drawing from a different set of heterogeneous studies, ignoring the basic assumptions required for MA, resulting in disparate results and conclusions. Previous MA show the large effects of study design, which results in inconsistent estimates of the effect of LCS on BW between MA of RCT and NRS. Given the availability of long-term RCT, these studies should be the basis of determining causal relationships (or lack thereof) between LCS and BW. This trial was registered at PROSPERO as CRD42022351200.