Nonsugar sweeteners should not be used for weight loss, WHO guideline states

The World Health Organization (WHO) recommended that nonsugar sweeteners (NSS) not be used for weight control or reducing the risk of noncommunicable diseases in a recent guideline.

The conditional recommendation is based on evidence of low certainty overall, which the WHO gathered in a systematic review that assessed the health effects of higher compared with lower intake of NSS. The systematic review, published by the WHO on April 12, 2022, found no evidence of long-term benefit from NSS in adults or children. It also found potential undesirable effects from long-term use in the form of increased risk of type 2 diabetes, cardiovascular diseases, and mortality in adults. The guideline appeared on the WHO website May 15.

Low-certainty evidence from randomized controlled trials showed that using NSS resulted in short-term reduced sugar and energy intake, lower body weight, and lower body mass index (BMI), the WHO noted. NSS use did not significantly affect other measures of body fatness or intermediate markers of cardiometabolic health, including glucose, insulin, or blood lipids (very low- to moderate-certainty evidence). Evidence from a small number of trials lasting six to 18 months did not suggest an effect on body weight, but the guideline noted the trials were difficult to interpret because of many differences in how they were conducted and how the results were reported.

The WHO noted that trials comparing intake of NSS directly with intake of free sugars mostly provided foods and beverages containing NSS or free sugars in addition to existing diets and therefore did not directly measure the effects of replacing free sugars with NSS. When NSS were compared with nothing/placebo or water, there were no effects on body weight or BMI. When a small number of RCTs assessed NSS specifically as replacements for free sugars, the effect on body weight was significantly weakened relative to that observed for NSS used in any manner, and an effect on BMI was no longer observed.

Evidence from prospective observational studies, with up to 10 years of follow-up, showed that higher intake of NSS was associated with higher BMI and increased risk of incident obesity, but not other measures of adiposity (very low- to low-certainty evidence). Higher intakes of NSS were associated with increased risk of type 2 diabetes, cardiovascular disease and mortality, and all-cause mortality in long-term prospective observational studies with average follow-up of 13 years (very low- to low-certainty evidence). There was no difference in overall cancer incidence or mortality (very low-certainty evidence). Use of NSS (predominantly saccharin) was associated with increased risk of bladder cancer in case-control studies (very low-certainty evidence).

The guideline recommended reducing free sugars in the context of achieving and maintaining a healthy diet. “Because free sugars are often found in highly processed foods and beverages with undesirable nutritional profiles, simply replacing free sugars with NSS results means that the overall quality of the diet is largely unaffected,” the guideline stated. “Replacing free sugars in the diet with sources of naturally occurring sweetness, such as fruits, as well as minimally processed unsweetened foods and beverages, will help to improve dietary quality, and should be the preferred alternatives to foods and beverages containing free sugars.”

Because the recommended intervention is a suggestion to not include NSS in the diet, it can be viewed as a dietary goal rather than a specific intervention, the guideline said. It should result in policies and actions through behavior change interventions, fiscal policies, regulation of the marketing of foods and beverages, product labeling, and reformulation of manufactured products, it noted.