It's also quite possible that artificial sweeteners may be safe in low amounts, but problems could arise when they are used in excessive quantities. By partially or mostly substituting stevia, you can reduce any potential risk.

Weight Loss
It would seem quite obvious that substituting a no-calorie sweetener to sugar would help reduce caloric intake and thus contribute to weight loss. And such is the case with aspartame. Researchers at the Center for the Study of Nutrition Medicine, Beth Israel Deaconess Medical Center, at Harvard Medical School in Boston, Massachusetts, studied the influence of aspartame on obesity (Blackburn, 1997). One hundred sixty-three women were randomly assigned to consume or to abstain from aspartame-sweetened foods and beverages for 16 weeks. Both groups were also actively involved in a weight-control program using a variety of modalities. At the end of the 16 weeks, both the group on aspartame and the group without the synthetic sweetener lost 10 kilograms. During the maintenance phase that lasted the next two years, women assigned to the aspartame-treatment group gained back 4.5 kilogram, whereas those not on aspartame gained back 9.4 kilograms, practically all the weight they had previously lost. The researchers state, "These data suggest that participation in a multidisciplinary weight-control program that includes aspartame may facilitate the long-term maintenance of reduced body weight."

Unfortunately, no formal studies have been done evaluating stevia substitution in relation to weight loss. We would suspect, though, that the results would be similar to the aspartame study discussed above. If you are the type of person who adds sugar to your morning coffee or tea, or to iced tea, lemonade, and a variety of desserts and baked goods, then, over time, the elimination of these refined sugar calories could make a significant difference.

Sweet Teeth with No Cavities
Even a five-year old child knows that sugar causes tooth cavities. There are certain bacteria in our mouths, particularly streptococci mutans, that ferment various sugars to produce acids. These in turn eat through the enamel of the tooth causing pockets or cavities. For a long time, scientists have searched to find alternative sweeteners that are not fermentable by bacteria and hence do not cause cavities. Artificial sweeteners have been helpful in this regard.

Does ingesting stevia lead to tooth cavities? A study done on rats has not shown this to be case. Stevioside and rebaudioside A, the two primary sweet constituents of the stevia plant, were tested in a group of sixty rat pups (Das, 1992) in the following way:

Group 1 was fed sucrose (table sugar), at 30 percent of their diet
Group 2 was given 0.5 percent of their diet in stevioside
Group 3 got 0.5 percent of their diet in rebaudioside A
Group 4 ingested no sugars.

After 5 weeks, all four groups had their teeth evaluated. There were no differences in food and water intake and weight gain between the four groups. However, the first group had significantly more cavities than the rest of the groups. Groups 2, 3, and 4 were equivalent. The researchers state, "It was concluded that neither stevioside nor rebaudioside A is cariogenic [cavity causing] under the conditions of this study." It appears that the chemicals within the stevia plant that impart its sweetness are not fermentable, and thus do not cause tooth cavities.