Study finds non-nutritive sweetened beverages more effective than water for weight loss

By Tarun Sai LomteOct 9 2023Reviewed by Lily Ramsey, LLM

In a recent study published in the International Journal of Obesity, researchers compared the effects of consuming non-nutritive sweetened (NNS) beverages and water after a weight management program.

Study: Non-nutritive sweetened beverages versus water after a 52-week weight management programme: a randomised controlled trial. Image Credit: TanyaKim/Shutterstock.com

Background

Sugar-sweetened beverages can lead to weight gain. As such, dietary guidelines recommend water or NNS beverages to limit overall sugar intake.

Nevertheless, the use of NNS beverages for weight management has been contentious due to their potential effects. Observational studies report that consuming NNS beverages is positively associated with gains in body mass index (BMI) and weight.

On the other hand, systematic reviews and meta-analyses have found modest weight loss and lower overall energy intake, with benefits on cardiometabolic health, among individuals consuming NNS beverages relative to those consuming sugar-sweetened drinks.

Notwithstanding, there is limited data on the impact of NNS beverages on long-term weight maintenance relative to water.

About the study

In the present study, researchers investigated the effects of water and NNS beverages on weight after active weight loss and weight maintenance phases of the effects of NNS beverages on appetite during a functional weight loss (SWITCH) trial.

Healthy individuals aged 18-65 with a BMI of 27 kg/m² to 35 kg/m², consuming more than three cold beverages weekly were included. A questionnaire was administered to assess habitual beverage consumption.

Individuals were excluded if they consumed less than three cold beverages weekly, had food allergies, diabetes, cardiovascular disease, intensive exercise, significant weight loss, or underwent bariatric surgery pre-screening. The trial involved active weight loss for 12 weeks, assisted weight maintenance for 40 weeks, and non-assisted maintenance extension for 52 weeks.

Participants were randomized to water or NNS beverages, stratified by sex, age, BMI, and NNS naivete, and instructed to consume ≥ 2 servings of 330 ml per day of water or NNS beverages.

Adherence was assessed through daily logs, food frequency questionnaires, and three-day food dairies. Weekly behavioral weight-loss sessions were offered for the first 12 weeks, and monthly sessions after that. The primary endpoint was body weight change at week 52 from baseline.

Secondary endpoints were changes in glycemic control, hip and waist circumference, liver function, hunger, fasting lipids, sugar/sweetener intake, and activity level (average number of steps per day).

The primary analysis included data from participants completing the trial up to 52 weeks. Sensitivity analyses were performed for changes in hip and waist circumference and body weight, with additional covariates (sex, age, weight measurement location) and NNS beverage naivete.

Findings

Overall, 493 individuals were randomized from July 2016 to December 2021. Only 262 subjects completed the 52-week time point, of which 93.6% attended monthly behavioral weight-loss sessions. Adherence was high in both groups (> 98.2%). About 70% of participants were female, and 75.9% were non-naïve to NNS beverages.

Both groups had the highest weight loss rate during the first 12 weeks, although the NNS beverage group had higher weight loss than the water group.

Maximum weight loss occurred at weeks 36 and 44 with NNS beverages and water, respectively, beyond which participants began to regain weight. The rate of weight recovery was slower in the NNS beverage group. Both groups demonstrated significant weight loss at week 52 relative to baseline.

The average weight loss was 7.5 kg with NNS beverages and 6.1 kg with water. Hip and waist circumference was also reduced. In a subset of participants who underwent full-body dual-energy X-ray absorptiometry (DXA) scans, there was a significant reduction in fat mass, gynoid/android fat distribution, and fat-free mass at week 52 in both groups.

The NNS beverage group showed a modest but significant increase in high-density lipoprotein cholesterol at week 52 relative to baseline.

Most biomarkers showed significant improvements at week 52 from baseline in both groups. Sweetener consumption was significantly lower only in the water group, but sugar consumption was significantly lower in both groups.

Activity levels at week 52 were significantly elevated with NNS beverages but reduced with water from baseline levels, although the difference was insignificant.

Conclusions

In sum, both groups lost weight during the trial, albeit the NNS beverage group achieved significantly higher weight loss than the water group.

Nevertheless, this difference was not clinically significant. Additionally, there were improvements in other anthropometric measures, biomarkers, and sugar consumption.

Further analysis into the 52-week voluntary extension phase will determine whether discontinuing nutrition awareness would impact weight loss maintenance.