Low-calorie sweeteners and body weight and composition: a meta-analysis of randomized controlled trials and prospective cohort studies

Publication Name: American Journal of Clinical Nutrition. 2014 Sep; 100(3): 765–777.

Author(s): Miller PE and Perez V | Publication Year: 2014

Abstract

Background: Replacement of caloric sweeteners with lower- or no-calorie alternatives may facilitate weight loss or weight maintenance by helping to reduce energy intake; however, past research examining low-calorie sweeteners (LCSs) and body weight has produced mixed results. Objective: The objective was to systematically review and quantitatively evaluate randomized controlled trials (RCTs) and prospective cohort studies, separately, that examined the relation between LCSs and body weight and composition. Design: A systematic literature search identified 15 RCTs and 9 prospective cohort studies that examined LCSs from foods or beverages or LCSs consumed as tabletop sweeteners. Meta-analyses generated weighted mean differences in body weight and composition values between the LCS and control groups among RCTs and weighted mean correlations for LCS intake and these parameters among prospective cohort studies. Results: In RCTs, LCSs modestly but significantly reduced all outcomes examined, including body weight (?0.80 kg; 95% CI: ?1.17, ?0.43), body mass index [BMI (in kg/m2): ?0.24; 95% CI: ?0.41, ?0.07], fat mass (?1.10 kg; 95% CI: ?1.77, ?0.44), and waist circumference (?0.83 cm; 95% CI: ?1.29, ?0.37). Among prospective cohort studies, LCS intake was not associated with body weight or fat mass, but was significantly associated with slightly higher BMI (0.03; 95% CI: 0.01, 0.06). Conclusions: The current meta-analysis provides a rigorous evaluation of the scientific evidence on LCSs and body weight and composition. Findings from observational studies showed no association between LCS intake and body weight or fat mass and a small positive association with BMI; however, data from RCTs, which provide the highest quality of evidence for examining the potentially causal effects of LCS intake, indicate that substituting LCS options for their regular-calorie versions results in a modest weight loss and may be a useful dietary tool to improve compliance with weight loss or weight maintenance plans.

Summary

There has been conflicting research on the role of low- and no- calorie sweeteners (LNCS) on body weight. This study represents an analysis of research from over 35 years examining the impact of LNCS on body weight, BMI, waist size and body fat. It provides a systematic analysis of both prospective populations’ studies and the gold standard study design in medical research, randomised controlled trials (RCTs). The authors performed a meta-analysis of the available literature, an approach that combines the findings from multiple studies (in this case, 15 RCT and 9 prospective observational cohort studies), summarizing overall impact in a quantifiable manner. The analysis of studies using the stronger study design, RCTs, showed that replacing sugar with LNCS resulted in modest, but significant reductions in body weight, BMI, waist size and body fat. In contrast to the findings from well-controlled randomised trials, results from the analysis of the prospective observational cohort studies showed a significant positive association between LNCS intake and BMI, and non-significant associations between LNCS intake and body weight and body fat. Authors noted that findings from a meta-analysis on these types of observational studies are not easily interpreted because few observational studies controlled for both total energy intake and baseline body weight. They further noted that reverse causality and inadequate assessment of baseline LNCS intake are important sources of bias that may impact the outcome. The authors conclude, “On the basis of the available scientific literature to date, substituting LCS options for their regular-calorie versions results in a modest weight loss and may be a useful dietary tool to improve compliance with weight-loss or weight-maintenance plans.”