Could Artificial Sweeteners Cause Weight Gain?
Researcher says evidence suggests they may, but industry rep disagrees
WebMD News Archive
She said she's seen evidence of metabolic disruptions caused by artificial sweeteners in rats.
It basically goes something like this: In a world without artificial sweeteners, a taste of something sweet preps the brain and the gut for digestion of incoming calories. When the calories don't show, as happens with artificial sweeteners, those metabolic responses don't fire the way they should. Insulin doesn't increase; hormones that increase the feeling of fullness and satisfaction aren't triggered; and the brain doesn't get a feeling of reward from the dopamine that sugars release.
After a while, Swithers said, it's like the mouth keeps crying wolf, and the brain and gut stop listening. As a result, when real sugar and real calories come along, the body doesn't respond to them as strongly as it normally might. Calories don't end up making you feel as full as they should. They aren't as rewarding. So you don't get the signals that might stop you from eating when you should.
Artificial sweeteners may also facilitate something psychologists call cognitive distortions. That is, they allow us to trick ourselves into thinking we can eat more calories than we really should. Saving calories with a diet soda now means a slab of chocolate cake is OK later.
"I think there are multiple things that are contributing to this," Swithers said. "Psychology is a factor, but physiology can also be altered."
Based on her research, she said, water is the best bet for people who are trying to lose weight or improve other measures of health.
"The downside to drinking the diet sodas is that they may undermine these unconscious processes that could help us regulate our weight and other things like blood sugar," she said.