In a recent study published in the International Journal of Obesity, researchers have shed light on the effectiveness of non-nutritive sweetened (NNS) beverages in comparison to water in a post-weight management program context.
The impact of sugar-sweetened beverages on weight gain has been well-documented. Consequently, dietary guidelines have recommended the consumption of water or NNS beverages as an effective strategy to curb sugar intake. Nevertheless, the suitability of NNS beverages in weight management has remained a topic of debate, primarily due to conflicting findings in observational studies and systematic reviews.
While some observational studies have suggested that the consumption of NNS beverages is linked to an increase in body mass index (BMI) and weight, systematic reviews and meta-analyses have pointed to modest weight loss and reduced overall energy intake among individuals opting for NNS beverages over sugar-sweetened counterparts. These studies have also suggested potential cardiometabolic health benefits associated with NNS beverage consumption.
However, there has been a scarcity of data concerning the long-term impact of NNS beverages on weight maintenance in comparison to water.
About the Study
This investigation aimed to assess the effects of water and NNS beverages on weight during the post-weight loss and maintenance phases following the functional weight loss (SWITCH) trial. The study recruited healthy individuals aged 18-65 with a BMI between 27 kg/m² and 35 kg/m², who consumed more than three cold beverages weekly. A detailed questionnaire was administered to gauge their habitual beverage consumption.
Participants were excluded if they consumed fewer than three cold beverages weekly, had food allergies, diabetes, cardiovascular disease, engaged in intensive exercise, experienced significant weight loss, or had undergone bariatric surgery during pre-screening. The trial consisted of an active weight loss phase lasting 12 weeks, a supported weight maintenance phase for 40 weeks, and a non-assisted maintenance extension period spanning 52 weeks.
Participants were randomly assigned to either the water or NNS beverage group, with stratification based on sex, age, BMI, and NNS beverage familiarity. They were instructed to consume at least two servings of 330 ml per day of water or NNS beverages. Adherence was monitored through daily logs, food frequency questionnaires, and three-day food diaries. Weekly behavioral weight-loss sessions were provided during the initial 12 weeks, followed by monthly sessions.
The primary outcome measured was the change in body weight at the 52-week mark relative to baseline. Secondary endpoints encompassed alterations in glycemic control, hip and waist circumference, liver function, hunger, fasting lipids, sugar/sweetener consumption, and activity levels (average daily step count). Sensitivity analyses were conducted for changes in hip and waist circumference and body weight, with additional covariates taken into account.
A total of 493 individuals were randomized between July 2016 and December 2021. Of these, 262 subjects completed the 52-week period, with an impressive 93.6% attending monthly behavioral weight-loss sessions. Adherence was remarkably high in both the water and NNS beverage groups, exceeding 98.2%. Approximately 70% of participants were female, and 75.9% were familiar with NNS beverages.
Both groups achieved their maximum weight loss rates during the initial 12 weeks, with the NNS beverage group exhibiting greater weight loss than the water group. Subsequently, participants in both groups started regaining weight, albeit at a slower pace in the NNS beverage group. Significantly, both groups demonstrated considerable weight loss at the 52-week mark relative to their baseline measurements.
On average, the NNS beverage group experienced a weight loss of 7.5 kg, while the water group lost 6.1 kg. Notably, there were reductions in hip and waist circumference as well. In a subset of participants who underwent full-body dual-energy X-ray absorptiometry (DXA) scans, both groups exhibited significant reductions in fat mass, gynoid/android fat distribution, and fat-free mass at week 52.
The NNS beverage group also displayed a modest but significant increase in high-density lipoprotein cholesterol at week 52 relative to baseline. Most biomarkers showed significant improvements at week 52 in both groups. Sugar consumption was significantly lower in both groups, whereas sweetener consumption was notably reduced only in the water group.
Activity levels at week 52 were significantly elevated with NNS beverages but decreased with water, though the difference was not statistically significant.