New research from the Netherlands suggests that replacing sugars with sweeteners and sweetness enhancers (S&SEs) could support weight loss and improve gut health in obese individuals. This finding challenges the World Health Organization's (WHO) existing guidance, which advises against using sweeteners for weight loss, citing concerns over increased risks of type 2 diabetes and heart disease, which they concluded outweigh the benefits of body fat reduction.

Published in the journal *Nature Metabolism*, the study claims to be the first to demonstrate benefits of S&SE intake in overweight and obese populations. Scientists found that switching from sugar to S&SEs could help participants lose an additional 3.5 lbs (approximately 1.6 kg) in body weight per year. Beyond weight loss, the research indicated that S&SEs could alter the gut microbiota—the community of bacteria, fungi, and viruses that aid digestion. This alteration included an increase in short-chain fatty acids (SCFAs) and gases, which break down non-digestible carbohydrates through fermentation, potentially aiding weight loss and regulating appetite.

The randomized trial involved 325 adults, with an average age of 47 (71% women), and 36 children, with an average age of 10 years (61% girls). Participants were randomly assigned to either a diet where sugar-rich products were replaced with S&SEs or one where they consumed sugar. All participants initially followed a healthy, low-sugar diet, with less than 10% of their energy derived from sugar. The intervention included an initial two months for weight stability in children and a 5% weight loss target for adults, followed by a 10-month weight loss phase with a healthy, flexible diet.

While both groups experienced weight reduction, the S&SE group achieved a slightly greater weight loss of 3.5 lbs. An analysis of the gut microbiota composition in a subgroup of 137 adult participants after 12 months revealed that the S&SE group had an increase in short-chain fatty acid-producing and methane-producing bacteria. The study also observed a larger reduction in BMI and improved levels of both good (HDL) and bad (LDL) cholesterol in adults within the S&SE group after six months, suggesting potential benefits for heart disease risk factors. However, no significant difference in childhood BMI outcomes was noted between the sugar and S&SE groups.

Despite these positive findings, the study acknowledged several limitations, including a participant dropout rate that was 10% higher than anticipated. Additionally, more adverse events such as abdominal cramps, loose stools, and excess intestinal gas were reported in the S&SE group. One of the authors disclosed receiving honoraria from Nestlé, Unilever, and the International Sweeteners Association.

This research contributes to an ongoing debate regarding artificial sweeteners. It follows recent warnings from other experts, including scientists at the University of Colorado, who found that erythritol, a 'sugar-free' and 'zero-calorie' sweetener, could cause damage within three hours of consumption, potentially raising the risk of blood clotting, inflammation, heart attacks, and strokes. Professor Christopher DeSouza, a lead researcher in that separate study, cautioned that seemingly 'safe' non-nutritive sweeteners might come with hidden health risks.