A篇阅读 Let's face it . No one drinks diet sodas for the taste . People drink diet sodas in the hope that it will help them lose weight or at least keep them from gaining it . Yet it seems to have exactly the opposite effect , according to a new study . Researchers from the University of Texas said those who drank two or more diet sodas a day had waist size increases that were six times greater than those who didn't drink diet sodas . "What we saw was that the more diet sodas a person drank , the more weight they were likely to gain , " said Sharon Fowler . The study was based on data from 474 participants in a large , ongoing research project , where the participants were followed for nearly 10 years . While the findings are surprising , they also offer some explanations . Nutrition expert , Melanie Rogers , who works with overweight patients in New York , has found that when patients are switched from regular to diet sodas , they don't lose weight at all . "We weren't seeing weight loss necessarily , and that was confusing to us , " said Rogers . So why would diet soda cause weight gain ? No one knows for sure yet , but it could be that people think they can eat more if they drink diet sodas , and so over - compensate (补偿) for the missing calories . A related study found some sweeteners (甜味剂) raised blood sugar levels in some mice . "Data from this and other potential studies suggest that the promotion of diet sodas and artificial sweeteners may be risky , " said Helen P . Hazuda , professor at the University of Texas's school of medicine . " They may be free of calories , but not of consequences . "(回答21-24题) 21.People drink diet sodas to ___ .