Study Linking Weight Gain and Heart Disease with Low Calorie Sweeteners Paints with Too Broad a Brush

By: Keri Peterson, MD —

July 17, 2017 — 12:01 AM — Obesity is a complex condition with numerous causes and associations. Due to its association with a number of negative health outcomes and chronic diseases, a variety of approaches to managing obesity have been explored in an attempt to identify how to best help individuals achieve and sustain healthy weight loss. Collectively, this research has shown that personalized, multifactorial and multidisciplinary approaches using a variety of tools can improve an obese individual’s success in losing weight. The study analysis, “Nonnutritive sweeteners and cardiometabolic health: a systematic review and meta-analysis of randomized controlled trials and prospective cohort studies” by Azad et al., took a broad approach of identifying studies related to low-calorie sweeteners (LCS) but did not consider the additional study aspects known to influence change in body mass index (BMI)

Publication Bias May Skew Findings

This meta-analysis is based on data from 7 randomized controlled trials (RCTs) including various LCS interventions that ranged from 6 to 24 months and 30 observational reports on 22 cohorts with follow-up ranging from 1 to 38 years. The authors report that the selected RCTs do not consistently show that consumption of LCS alone results in weight loss or reduction in BMI. While the authors note differences in the weight-loss effects in RCTs and suggest that funding could be a source of bias that could not be evaluated, the studies also differ significantly in intervention design and duration which have known roles in obesity intervention outcomes.

The authors found that the observational studies suggest that long-term LCS intake may be associated with diabetes risk, but that publication bias may skew their analysis and experimental studies have not confirmed these findings. Additional associations of LCS intake with increased risk for cardiometabolic disease and high BMI were based on observational studies that prevent determining if the relationship is causal. It is also important to note that observational cohort studies are at risk for residual confounding and reverse causality. For example, researchers admit that less than 50% of the cohort studies controlled for ethnicity or socioeconomic status which are both known risk factors for obesity and cardiometabolic illness. Further, previous research has shown that LCS consumers begin using or increase consumption of LCS as a way to manage pre-existing diseases like diabetes which are brought on by genetic or lifestyle factors.

Obesity Cannot Be Generalized

The Calorie Control Council’s Medical Advisor, Keri Peterson, MD, notes that the

Management of obesity leading  to sustained weight loss requires a multifactorial approach and is best achieved by individualizing the approach. Effective  behavioral change is best enabled by addressing learned behaviors that lead to excessive food intake and evaluating causes of a sedentary lifestyle. This can only be done by taking the time to learn about my patients.

Because obesity is often times associated with other negative health outcomes, Azad et al., also conducted secondary evaluations and noted that LCS intake is associated with higher risks of obesity, hypertension, metabolic syndrome, type 2 diabetes, stroke and cardiovascular disease events. The researchers note that RCTs do not confirm these associations and identified a publication bias which favored reporting positive associations between LCS and type 2 diabetes.

“Low-calorie sweeteners are a tool to help provide sweet taste without calories to address one aspect of calorie intake. Taste preferences are an important component of dietary habits but successful weight management requires a well-rounded strategy”, says Robert Rankin, President of the Calorie Control Council. “Individualized strategies are critical for successful body weight management and should address not only dietary preferences, but also physical activity, and medical considerations to help each person achieve their health goals, including those related to chronic diseases such as cardiovascular disease, diabetes, obesity and hypertension.”