The meta-analysis looked at data from randomised controlled trials (RCTs) and prospective cohort studies and contained information from almost study 2,000 participants. Writing in the American Journal of Clinical Nutrition, the team behind the research reported thatdata from RCTs showed that low-calories sweeteners (LCSs) 'modestly but significantly' reduced measures of weight, while the data from prospective cohort studies did not show significant results with regard to weight loss.
"The current meta-analysis provides a rigorous evaluation of the scientific evidence on LCSs and body weight and composition," wrote the team, led by Paige Miller from US-based scientific consulting firm Exponent Inc.
"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," they said.
The study was supported by the North American branch of the International Life Sciences Institute (ILSI North America).
The Exponent Inc researchers performed a systematic literature search which identified 15 RCTs and 9 prospective cohort studies that examined LCSs from foods or beverages or LCSs consumed as tabletop sweeteners. Analysis of this data indicated that substituting LCS for sugar modestly reduces body weight, BMI, fat mass, and waist circumference.
The team noted that although the mean reduction in body weight was modest (0.80-kg decrease), it would not be expected for a single dietary change, i.e., replacement of sugar with LCS, to cause clinically meaningful weight loss. Rather, leading nutrition and health authorities recommend a multifaceted approach to weight loss and weight maintenance—one that includes an overall healthy dietary pattern, physical activity, and other lifestyle behaviour changes.
"By maintaining the palatability of foods and beverages with fewer calories than sugar, LCS could help improve adherence to weight-loss or maintenance plans," said the team.
They also examined the relation between LCS intake and body weight and composition among prospective cohort studies. This meta-analysis showed statistically non-significant associations between LCS intake and body weight and fat mass, but a significant, albeit modest, positive association with BMI.
"In conclusion, the meta-analysis of observational studies showed a small positive association between LCS intake and BMI, but no association with body weight or fat mass. On the other hand, data from RCTs, which provide the highest quality of evidence for examining the potentially causal effects of LCS intake on body weight, indicate that substituting LCSs for calorically dense alter- natives results in a modest reduction of body weight, BMI, fat mass, and waist circumference," concluded the team.
"On the basis of the available scientific literature to date, substituting LCS options for the irregular-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."
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.113.082826
"Low-calorie sweeteners and body weight and composition: a meta-analysis of randomized controlled trials and prospective cohort studies"
Authors: Paige E Miller, Vanessa Perez