The new Dietary Guidelines for Americans, 2025–2030 promote a “real food” approach that prioritises minimally processed, nutrient-dense foods while discouraging consumption of highly processed products and food additives, including low/no calorie sweeteners. However, the recommendation regarding low/no calorie sweeteners is weakly substantiated and appears to be driven more by the ideology about “processing” than by a balanced consideration of the available scientific evidence.
The new guidelines recommend to reduce both added sugars and low/no calorie sweeteners. It asserts, without nuance, that low/no calorie sweeteners are not part of a healthy diet at any level of intake. This absolute position is striking given current evidence showing potential benefits when low/no calorie sweeteners replace sugars.1
The evidentiary basis used to support these recommendations about sweeteners is inconsistent with standards stated in the Scientific Foundation for the guidelines.2 Although the guidelines claim to prioritize strong causal evidence from randomized controlled trials (RCTs), they largely rely on observational studies that identify only weak and inconsistent associations between low/no calorie sweetened beverages and cardiometabolic outcomes.3 At the same time, much of the RCT evidence is dismissed because trials are shorter, smaller, or focus on intermediate outcomes rather than “hard” clinical endpoints. This results in an internally contradictory methodology: RCTs are declared the “gold standard,” yet their findings are effectively sidelined when they do not align with the desired narrative.
A major limitation is that the recommendation to limit low/no calorie sweeteners is grounded in observational evidence that is vulnerable to confounding and reverse causation (for example, individuals with obesity or diabetes may be more likely to choose low/no calorie sweeteners).4 In contrast, high-quality RCTs and bias-adjusted observational prospective cohort analyses demonstrating benefits of substituting low/no calorie sweeteners for sugar including reductions in body weight and cardiometabolic risk are acknowledged in the umbrella review3 but not incorporated into the final guidance. Another recent thorough umbrella review of meta-analyses of both RCTs and prospective cohort studies revealed a significant methodological divide: while “naïve” analyses of cohort studies with prevalent (signle baseline) exposure assessment often associate low/no calorie sweeteners with increased risks of obesity, diabetes and cardiovascular disease, “bias-adjusted” analyses showed the opposite, aligning with clinical trial data.4 Specifically, when low/no calorie sweeteners were used to replace sugar and reduce overall calories, they were consistently associated with reductions in body weight, body fat, and energy intake in RCTs, and lower body weight, obesity, coronary heart disease, cardiovascular and all-cause mortality in bias-adjusted analyses of prospective cohorts.
This selective interpretation of evidence raises the possibility of confirmation bias, especially given the overarching principle against highly processed foods. The report calls for more long-term RCTs with clinical endpoints, but such trials are complex and unrealistic, further complicating the evidence expectations.
Overall, the recommendation to limit low/ no calorie sweeteners is not supported by the totality of available evidence.4,5 The exclusion or down-ranking of RCTs and bias-adjusted cohort studies that show potential benefits of low/ no calorie sweeteners substitution is difficult to reconcile with claims of evidence-based guidance. The current stance appears to be driven more by a prescriptive “real food” philosophy than by balanced scientific evaluation. Consequently, the recommendation about low/no calorie sweeteners should be revised or explicitly justified, rather than presented as an evidence-based conclusion.