A natural, calorie-free sweetener approximately 200 to 300 times as sweet as sugar? Sounds too good to be true, but it's not -- it's stevia. This ultra-sweet plant originated in South America, but it's been used in many countries for hundreds of years as a natural sweetener. Using stevia in place of sugar can cut calories and may keep your blood glucose level more stable, according to University of Utah Health Care. Whether you're diabetic or just looking for a natural alternative to white sugar, saccharin or aspartame, stevia is a good choice.