With the holidays-related consumption of rich, sweet and ever-so-plentiful cookies, cakes and other sweets quickly fading, and the annual act of making deliberate, positive resolutions for the New Year upon us, many people focus on decreasing the consumption of sugar and other simple carbohydrates. In fact, the 2018 Annual Food and Health Survey conducted by the International Food Information Council (IFIC) Foundation1 found that 77% of Americans are limiting/avoiding sugars in the diet. While the majority of the respondents (approximately 60%) stated that they would be drinking water instead of caloric beverages, more than 20% indicated that they would be switching to low- or no-calorie beverages or using low-calorie sweeteners instead of adding sugar. However, does the switch to low-calorie sweeteners (LCS, also termed non-nutritive sweeteners) have robust scientific data to support that the switch to LCS decreases body weight and reduces the risk of Type II diabetes and other adverse health conditions?
The Food Forum of the National Academies of Sciences, Engineering and Medicine2 recently sponsored a webinar entitled “Current and Emerging Knowledge and Research on Non-Nutritive Sweeteners,” featuring the speakers Dr. Allison Sylvetsky from the Milken Institute School of Public Health, The George Washington University, and Dr. Frank Hu from the Harvard T.H. Chan School of Public Health. Dr. Sylvetsky focused on consumption trends and findings of LCS through mechanistic and observational studies. LCS are defined as substances that are many times sweeter than sugar, such that the amount needed to reach an equivalent sweetness results in minimal calorie intake from these sweeteners. Examples include sucralose, aspartame and the rebaudiosides from the Stevia plant. LCS intake has significantly increased in the United States from 1999 to 2012 across all sociodemographics, and the number of overweight/obese people or people with Type II diabetes has also significantly increased during that same general period;3 could consumption of LCS be a cause for increased body weight and Type II diabetes?
When substituting sugar-sweetened beverages (SSB) for LCS-containing beverages, one would assume a decrease in body weight would occur, resulting in improved body mass index (BMI), a typical indicator of body fat based on weight and height4. However, a meta-analysis conducted by Azad et al.5 found that increased consumption of LCS had no significant effect on BMI, when evaluating seven randomized controlled trials (RCTs) that met the inclusion criteria. When evaluating 30 observational cohort studies (405,907 participants with a median follow-up of 10 years) that met the inclusion criteria, consumption of LCS was associated with a modest increase in BMI (mean correlation 0.05, 95% confidence interval 0.03–0.06). The authors concluded that evidence from RCTs “does not clearly support the intended benefits of nonnutritive sweeteners for weight management.” Dr. Hu conducted a detailed analysis of various RCTs and meta-analyses published in the last 10 years on the subject of LCS and weight loss or other metabolic outcomes, and noted that in 2014 Miller and Perez concluded through a meta-analysis of RCTs that “substituting LCS options for their regular-calorie versions results in a modest weight loss.”6 Dr. Hu pointed out that the Azad et al.5 meta-analysis utilized a subset of the RCTs cited in the Miller and Perez study,6 underscoring the fact that subtle changes in evaluating data can have a significant impact on study conclusions. Dr. Hu concluded that while RCTs are the “gold standard” in clinical trials, there are limitations of RCTs when evaluating LCS and weight control, as RCTs typically have: (1) small sample size, (2) decreased compliance and high dropout rates, (3) small choices in comparison groups, (4) poorly defined intervention endpoints, (5) RCTs do not reflect “real-world” consumption patterns, (6) different types of LCTs are compared, and (7) healthy individuals may be compared to clinical patients between RCTs. Any or all of these factors may influence the interpretation of RCT trials.
Dr. Hu concluded his presentation by citing the American Heart Association’s Scientific Advisory publication7 which stated that “[F]or adults who are habitually high consumers of SSBs [sugar-sweetened beverages], the writing group concluded that LCS beverages may be a useful replacement strategy to reduce intake of SSBs,” although water is the preferred substitute. Overall, Dr. Hu and Dr. Sylvetsky agreed that while the results of RCTs evaluating the ability of LCS to promote long-term weight loss may be contradictory at times, there have been many toxicology studies conducted on the LCS that have shown that these non-nutritive sweeteners are safe. The concluding message coming from the presentations was that while a switch from sugar-sweetened beverages to LCS will decrease caloric intake to some extent, this switch by itself will not reverse the increases in obesity and other associated adverse health conditions, and that there are multiple factors that contribute to weight gain or weight loss. A reduction in caloric intake along with additional diet and exercise continue to be the best steps to decrease weight gain.
References:
International Food Information Council (IFIC) Foundation (IFIC, 2018); 2018 Food & Health Survey. Site last visited Jan. 3, 2019.
Food Forum (2018); WEBINAR: Current and Emerging Knowledge and Research on Non-Nutritive Sweeteners. Site last visited Jan. 3, 2019.
American Society for Metabolic & Bariatric Surgery (ASMBS, 2013). Type 2 Diabetes and Obesity: Twin Epidemics. Site last visited Feb 3, 2022.
National Institutes of Health (NIH) (2018). Calculate your Body Mass Index. Site last visited Jan. 3, 2019.
Azad MB, Abou-Setta AM, Chauhan BF, Rabbani R, Lys J, Copstein L, Mann A, Jeyaraman MM, Reid AE, Fiander M, MacKay DS, McGavock J, Wicklow B, Zarychanski R.(2017). Nonnutritive sweeteners and cardiometabolic health: a systematic review and meta-analysis of randomized controlled trials and prospective cohort studies. Canadian Medical Association Journal. 17;189(28):E929-E939. doi: 10.1503/cmaj. 161390
Miller, P.E. and Perez. V. (2014). Low-calorie sweeteners and body weight and composition: a meta-analysis of randomized controlled trials and prospective cohort studies. American Journal of Clinical Nutrition. 100(3):765-777.
Johnson et al. (2018). AHA Science Advisory. Low-calorie sweetened beverages and cardiometabolic health. Circulation;138:e126–e140. DOI: 10.1161/CIR.0000000000000569.