The study was published in eBioMedicine, part of the Lancet Discovery Science Journal. It aimed to evaluate acute (one day) and repeated (two-week daily) consumption effects of two sweeteners – neotame and stevia rebaudioside M, a molecule found in the stevia leaf – on appetite and endocrine responses in adults with overweight and obesity, compared with sucrose or table sugar.
The randomised crossover trial involved 53 adults (33 female, 20 male) with overweight or obesity across England and France. Participants consumed biscuits with fruit filling containing neotame, stevia rebaudioside M, or sucrose daily during three two-week intervention periods, including a two-week washout period.
Various measures were taken from the participants, including blood samples, appetite ratings, and assessments of food preferences. The primary outcome of the study was the composite appetite score, which was defined as [desire to eat + hunger + (100 − fullness) + prospective consumption], while secondary outcomes included glucose and insulin responses, as well as ghrelin, glucagon-like peptide 1, and pancreatic polypeptide levels.
The team found that neotame, stevia rebaudioside M, and sucrose-sweetened biscuits produced similar reductions in appetite sensations. Postprandial insulin levels were lower after consuming neotame and stevia rebaudioside M-sweetened biscuits, compared with sucrose.
Glucose levels were lower after stevia rebaudioside M consumption. No significant differences were recorded between sweetener and sucrose formulations on ghrelin, glucagon-like peptide 1, and pancreatic polypeptide levels.
In addition, no clinically meaningful differences were found between acute and repeated consumption of the sweeteners in terms of appetite or endocrine responses.
The University of Leeds research team, who have collectively received research funding from the American Beverage Association, consultancy fees from companies within the food and beverage industry, and honoraria from Nestlé, Unilever, and the International Sweeteners Association, among others, say their research provides “very strong evidence” that sweeteners, neotame, and stevia rebaudioside M do not negatively impact appetite and are, in fact, beneficial for reducing sugar intake.
WHO recommends against using non-sugar sweeteners for weight management
Using sweeteners for weight control or to lower the risk of non-communicable diseases has been the subject of much controversy over the years. In May 2023, the World Health Organization (WHO), after conducting a research review, published a guideline on non-sugar sweeteners (NSSs), recommending against their use to control body weight or reduce the risk of non-communicable diseases.
Since the release of these guidelines, many experts in the field have weighed in. Experts at Harvard TH Chan School of Public Health agreed with the WHO recommendations but did have criticisms that the meta-analysis excluded certain large studies.
Valisa Hedrick, associate professor at Virginia Tech’s Department of Human Nutrition, Foods and Exercise, and colleagues published an article in the British Medical Journal (BMJ) arguing that the current evidence on NSS intake is inadequate and further research is needed.
More consumers are actively avoiding sugar to manage their health
Weight management products often use NSSs in place of sucrose so that the products maintain sweetness, without added calories and the glucose spikes that may come with consuming sugar. However, as the 2023 WHO guidelines suggest, NSSs used in food products might not provide any long-term benefit in decreasing body fat.
Sugar is a major sticking point for many consumers. According to Mintel insights from 2024, a growing number of consumers are actively avoiding sugar to manage their health. When it comes to product innovation, there has been a rise in "no added sugar" claims in food and drink launches, which Mintel said may reflect consumer concern about high blood sugar levels and the importance of managing glucose intake.
Meal replacement brand Huel, for instance, provides products like powders, protein shakes, and bars, which it says are designed to meet the complete nutritional needs of consumers. While not marketed as a weight loss product, Jessica Stansfield, junior nutrition manager at Huel (which was not involved in the study), said its products can be useful to aid in weight loss, maintenance, or weight gain goals.
The no-prep meal company uses a variety of sweeteners to sweeten its products, including sucralose and steviol glycosides. When asked why Huel chooses to use these over other sweeteners, Stansfield told Vitafoods Insights that Huel aims to give consumers choices as some do not enjoy the taste of one over the other.
Stansfield went on to explain how the company has considered other sweeteners, using monk fruit, which is 100 to 250 times sweeter than sugar, as an example. The safety of monk fruit has been approved in many countries, she said; however, the European Food Safety Authority (EFSA) has not currently licensed it for use in the UK, where Huel is based.
Polyols may have contributed to reduced insulin and glucose response
In the University of Leeds study, polyols were used as bulking agents in the neotame and stevia rebaudioside M-sweetened biscuits to match the functionality of sucrose. Polyols, such as maltitol and sorbitol, are low digestible carbohydrates known to have a lower impact on blood glucose levels than sucrose, as they are not fully absorbed in the small intestine and therefore do not contribute to the same extent to postprandial glucose spikes.
When asked about the study's findings, Huel’s Stansfield said: “This raises the question: could these polyols have influenced the reduced insulin and glucose response after meals?”
In addition, the study's small sample size raised questions about the generalisability of the findings, and further research and replication studies to validate these findings and address limitations may be required.
EFSA scientists are currently re-evaluating the safety of all sweeteners that were permitted for use in foods before 20 January 2009.
