Mice put on a completely sugar-free low-fat diet for 16 weeks developed worse blood sugar control and insulin resistance than mice fed the same diet with normal sucrose. The findings were presented at ENDO 2026, the Endocrine Society's annual meeting in Chicago, on June 13.
This is animal research, not a human trial. The sugar-free mice also showed gut microbiome disruption, intestinal inflammation and early signs of fatty liver disease, and they did not weigh more than the controls.
The work came out of the Dasman Diabetes Institute in Kuwait City. Rasheed Ahmad, principal scientist at the institute, said "completely removing sucrose from a low-fat diet may unexpectedly disrupt gut health and promote inflammation and metabolic dysfunction."
What the mice actually showed
Over 16 weeks, the sugar-free group's ability to clear sugar from the blood weakened, a change called impaired glucose tolerance. Their cells also became less responsive to insulin, the hormone that shuttles glucose into cells.
Also read: 8 warning signs of COPD that appear years before most people are ever diagnosed
The trillions of bacteria in their gut, known as the gut microbiome, shifted out of balance. Their colon showed inflammation, and their livers began to show early fatty changes.
Body weight did not differ between the two groups. That matters, because it suggests the metabolic problems were driven by diet composition rather than by weight loss or gain.
The caveat that matters most
The mice were fed a diet with zero sucrose. That is not what public-health guidance asks of anyone.
The American Heart Association advises that women hold added sugars to about 25 grams a day, and men to about 36 grams. That is a ceiling on added sugar, not an instruction to strip carbohydrate out of the diet altogether.
Also read: How eating pumpkin seeds every day can affect your sleep, heart and prostate
Ahmad framed the takeaway in the same terms, saying "balanced nutrition is more important than simply eliminating sugar."
What the study does not show
The study does not show that a person will develop insulin resistance or fatty liver by cutting sugar. It tests mice, not humans, and mouse metabolism is not identical to human metabolism.
Conference presentations also have not gone through the full peer-review process that a published journal article requires. Replication in human trials would be needed before the finding could reshape any dietary recommendation.
What the animal data raise is a mechanistic question. The gut microbiome may need some fermentable carbohydrate to function well, and stripping out sucrose entirely may starve certain bacteria of a substrate they rely on.
Also read: Ultra-processed food may be quietly dulling your focus, even if you eat well otherwise
For most people, cutting back on added sugars in sweetened drinks, desserts and breakfast cereals remains the best-supported advice. Anyone worried about their blood sugar or gut health should talk to their doctor rather than swing to a zero-sugar extreme.
Also read: If you take a statin for cholesterol, these foods may affect how it works
This article is made and published by Jesper Bengtson, who may have used AI in the preparation.