Complete Sucrose Removal from Low-Fat Diet Disrupts Gut Microbiome and Metabolic Health in Mouse Study
Key Insights
Mice fed a sucrose-free, low-fat diet for 16 weeks developed impaired glucose tolerance and reduced insulin sensitivity despite similar calorie intake and body weight as controls.
The sugar-free group showed lower levels of beneficial gut bacteria including Lactobacillus murinus (search) and increased inflammation in both the colon and liver.
Researchers at the Dasman Diabetes Institute presented the findings at ENDO 2026, emphasizing that balanced nutrition is more important than simply eliminating sugar.
Researchers at the Dasman Diabetes Institute in Kuwait have found that completely eliminating sucrose from a low-fat diet may unexpectedly disrupt gut health and promote inflammation and metabolic dysfunction in mice, challenging assumptions about the universal benefits of sugar-free eating patterns.
"Completely removing sucrose from a low-fat diet may unexpectedly disrupt gut health and promote inflammation and metabolic dysfunction, highlighting that balanced nutrition is more important than simply eliminating sugar," said Rasheed Ahmad, Ph.D., principal scientist and head of the Immunology & Microbiology Department at the Dasman Diabetes Institute, in Kuwait City, Kuwait. The institute was founded by the Kuwait Foundation for the Advancement of Sciences.
The findings were presented at ENDO 2026, the annual meeting of the Endocrine Society, and have yet to undergo peer review.
Study Design and Key Findings
The researchers divided 12 healthy mice of similar weight into two groups. The control group consumed a low-fat diet containing sucrose, while the experimental group ate a sucrose-free, low-fat diet. Both groups received similar calorie amounts over the 16-week study period to rule out differences in food intake contributing to the findings.
Despite maintaining similar body weights and liver weights between the two groups, mice on the sucrose-free diet showed signs of worsening metabolic health. This group demonstrated impaired glucose tolerance and reduced insulin sensitivity, both of which are linked to an increased risk of type 2 diabetes (search). The researchers also observed significant changes in hormones involved in metabolism and appetite regulation, as well as lower fasting insulin levels.
Gut Microbiome Disruption and Inflammation
One of the most notable findings involved changes in the gut microbiome. The sugar-free group exhibited lower levels of several beneficial bacteria that help support gut health and regulate inflammation, including Lactobacillus murinus (search). Additionally, the researchers noted an increase in bacteria linked to inflammatory conditions, which was accompanied by signs of inflammation in the colon.
The sugar-free mice also developed signs of fatty liver disease (search) and liver inflammation, further underscoring the systemic nature of the metabolic disruption observed.
"The findings suggest that complete removal of sucrose from a low-fat diet may negatively affect gut microbiota and metabolic health," Ahmad said. "The study highlights the importance of maintaining balanced dietary carbohydrates to support gut and immune homeostasis."
Implications and Expert Reactions
According to the researchers, little was previously known about the potential consequences of highly restrictive low-fat diets that eliminate sugar entirely. "This research may influence future dietary recommendations by emphasizing the importance of maintaining a healthy gut microbiome rather than focusing only on sugar restriction," Ahmad said. "In the long term, these findings could help improve strategies for preventing and managing metabolic disorders, fatty liver disease (search) and chronic inflammatory conditions."
Faisal Hamed Al-Refaei, MD, Acting Director General of Dasman Diabetes Institute, added: "Studies such as this reflect our institute's commitment to advancing evidence-based scientific discoveries that improve public health outcomes and deepen our understanding of metabolic disease."
External experts urged caution in interpreting the findings. Mir Ali, MD, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center, who was not involved in the research, told Medical News Today: "I was surprised to see this result, as reducing carbohydrate and sugar intake is the mainstay of a number of successful weight loss strategies." He noted that a large body of research supports the health benefits of reducing added sugar intake and cautioned against overinterpreting the findings. "Overall, I think the positive benefits outweigh the possible negative effects," Ali offered.
Nneoma Oparaji, MD, a Houston-based physician specializing in lifestyle medicine and obesity medicine, likewise not involved in the research, emphasized: "The biggest takeaway is not to focus on a single nutrient or single study. Healthy eating is about overall dietary patterns, not a single ingredient."
Ali further stressed that further studies need to focus on humans to see whether these results carry over, and recommended that patients on a weight loss journey "emphasize protein and vegetables in the diet and reduce carbohydrates and sugars," citing sufficient evidence supporting this approach for fat burning and overall metabolic health.