According to a just released study, artificial sweeteners like Saccharin, Sucralose and Aspartame might contribute to higher blood sugar levels, thus contributing to weight gain despite their zero-calorie status. With their use now ubiquitous, and Diet Coke having passed Pepsi as the #2 soda sold in America a few years ago, scientists have been actively debating the benefits of these products for weight loss. Although multiple studies have shown a higher incidence of obesity among active consumers of zero-calorie sweeteners, its been hard to separate correlation and causation.
In the latest study researchers at the Weitzman Institute of Science focused on how the sweeteners impacted the composition of bacteria in the stomachs of mice. What they found was that a regular diet of what brands like Splenda and Equal are made of significantly changed the bacterial composition in their stomachs, which in turn impacted their ability to properly process glucose (i.e. normal sugar). When they tested the stomach bacteria composition of people that regularly consume these products with those that don't, they found significant differences.
The researchers then took a final step of recruiting 7 volunteers who don't normally consume artificial sweeteners and giving them larges doses. After a few days 4 of those volunteers recorded higher blood sugar levels. As you could imagine 4 of 7 does not make for a statistically significant study, but the theory they are testing presents an interesting opportunity.
One of the difficulties of studying nutrition is what works for one person sometimes doesn't for another, but as the master of your own body, you can always experiment to see what works for you. So if you've been struggling to lose weight and are a regular consumer of artificial sweeteners, try going without them for a few weeks and pay attention to changes in your body. There is another not yet fully tested theory that despite having no calories the sweet taste of these additives still triggers an insulin response which could theoretically make you crave other foods.