A study has found that artificial sweeteners help gut health. Artificial sweeteners deliver strong sweetness but are considered to have zero calories, allowing people to eat them without the weight-gain worries associated with sugar.
A research team led by Prof. Ellen Blaak at Maastricht University in the Netherlands said in Nature Metabolism on Feb. 17 (local time), "People who consume artificial sweeteners instead of sugar have gut microbes that help with weight management."
According to the researchers, 341 adults with obesity and a body mass index (BMI, weight divided by height squared) of 25 or higher ate low-calorie foods for two months and then followed a healthy diet for 10 months as a maintenance period. During maintenance, daily sweet intake was kept below 10% of total calories. Half of the participants consumed sugar, and the other half consumed sweeteners instead of sugar.
Participants lost an average of 10 kilograms during the diet period. During maintenance, those who consumed artificial sweeteners lost an average of 1.6 kilograms more than those who consumed sugar. The researchers noted, "The gut microbiomes of those who consumed sugar and those who consumed sweeteners were different."
Those who consumed artificial sweeteners had more gut microbes that break down dietary fiber to produce short-chain fatty acids with six or fewer carbon atoms. Short-chain fatty acids stimulate bowel movements and increase the water content of stool, helping with constipation and weight loss.
Artificial sweeteners are drawing attention as low-sugar foods gain popularity. In the past, sweetness was achieved with fructose found in fruit or honey. Fructose is easily absorbed, raises blood sugar, and can cause diabetes if consumed excessively. Alternative sweeteners are poorly absorbed and are excreted in urine, resulting in a lower calorie burden.
However, that does not mean artificial sweeteners can be consumed without limits. The World Health Organization (WHO) warned in 2023 that artificial sweeteners may increase the risk of stroke. Experts advise that changing a diet that favors sweetness and exercising are the surest ways to protect health.
References
Nature Metabolism (2025), DOI: https://doi.org/10.1038/s42255-025-01381-z