The bacteria in the gut interact with sugar to affect how leaky the gut is in fruit flies and human gut cells in a lab setting.

When fruit flies eat normal food, removing their gut bacteria makes their gut more leaky, but when they eat a lot of sugar, removing gut bacteria doesn't change gut leakiness.

Eating a lot of sugar makes the gut more leaky in fruit flies and human gut cells in a lab setting, which can be seen when blue dye leaks out of the gut in flies or when a special dye passes through gut cells more easily.

Eating a lot of sugar makes fruit flies have smaller guts and smaller bodies overall.

Eating a lot of sugar makes a protective enzyme called intestinal alkaline phosphatase less active in fruit flies and human gut cells in a lab setting.