*Aspartame and other calorie-free sugar substitutes can change the way a body processes fat and likely prompt diabetes and obesity, just like real sugar does.
*The way artificial sweeteners are digested inside the body is different from how real sugar is processed, but the negative outcomes may be nearly identical.
*Artificial sweeteners may also make people hungrier and, in turn, eat more. Scientists think that's because the zero-calorie treats turn on neural pathways that tell us to fuel up when we're starving.
If you're adding artificial sweeteners like aspartame into your coffee or tea, or sipping diet sodas to stay slim, you may not be doing your body any long-term favors.
Scientists have suspected for years that artificial sweeteners may stimulate our appetites and make us eat more. But forthcoming research suggests that's not the only piece of bad news about fake sugar.
In a new study, rats who were fed the common sweeteners aspartame and acesulfame K — found in products like Equal, NutraSweet, Sunett, and Sweet One — changed the way their bodies processed fat and energy. In the rats, this also led to muscle breakdown. The researchers think that the rats might've been tapping into their muscles as an alternative energy source, since the no-calorie sweeteners don't provide any nutrition.
The changes they saw in the rat bodies also appeared to set them up for developing chronic weight and sugar-processing problems, namely, diabetes and obesity. Those same mechanisms could be at work when humans drink fake sugar, though more research is needed to know for sure.
Brian Hoffmann, a biomedical engineer who studies high-sugar and high-sweetener diets at the joint Department of Biomedical Engineering at the Medical College of Wisconsin and Marquette University, presented his yet-to-be published research at the 2018 Experimental Biology conference in April.
"Non-caloric artificial sweeteners are foreign chemicals that your body does not have the machinery to deal with," Hoffmann said in a Q&A with Research Features. "Even those marketed as 'natural' because they are from a plant are foreign and it does not mean your body has the machinery to process them," he said.
But the International Sweeteners Association was quick to point out that this study didn't examine people.
"The ISA would like to highlight that this study does not provide evidence that low calorie sweeteners could adversely affect obesity or diabetes in humans," the trade organization told Business Insider in an email.
The research to date on artificial sweeteners like aspartame has been conflicting and confusing. Some studies have suggested that zero-calorie sweeteners can help people lose weight, but even that research points out that reduced calorie beverages won't dampen your appetite. French scientists have discovered a link between artificially sweetened beverages and higher rates of type 2 diabetes, but they're still not positive the artificial sweeteners are actively causing the diabetes.
The potential problems with artificial sweeteners don't stop at the digestive tract. One small study of a dozen women at the University of California San Diego found that while artificial sweeteners taste sweet, they don't satisfy our brains in the same way as sugar.
Researchers who asked people to sip sugar water or sucralose (Splenda-sweetened) water noticed that only those who swallowed sugar activated the region of the brain associated with food rewards. That suggests zero calorie drinks may not satisfy the mind's craving for something sweet. Other studies in fruit flies have suggested that when we eat or drink artificial sweeteners, we are likely tricking our bodies into thinking we're starving. This could potentially make people eat more, too (that said, humans aren't fruit flies, so more research is needed).
"It is not as simple as 'stop using artificial sweeteners' being the key to solving overall health outcomes related to diabetes and obesity," Hoffmann said in a release. "As with other dietary components, I like to tell people moderation is the key if one finds it hard to completely cut something out of their diet," he said.