Sweeteners such as sucralose seem to affect the way the body handles sugar, or glucose, in the blood. They also appear to raise glucose levels after a meal, which means the body must produce more insulin to break it down, and that's the start of a cycle that can lead to type 2 diabetes, say researchers from the Adelaide Medical School.
This process can begin within 14 days of using sweeteners, the researchers discovered when they gave 27 healthy volunteers high doses of sucralose, often marketed as Splenda—the equivalent of drinking 1.5 litres of diet drink—or a placebo. At the end of the two-week test, those given sweeteners saw a change in their glucose absorption, as well as their blood glucose and insulin levels.
The discovery is in line with earlier research that had found that sweeteners change the bacteria in the gut which lessens the body's ability to break down glucose.