Yacon is an edible root native to regions surrounding the Andes mountains. Like bananas, leeks, onions, garlic and barley, yacon is high in fructooligosaccharides, sweet-tasting and indigestible substances that are often used as a sugar alternative. Fructooligosaccharides have a prebiotic effect, helping to promote healthy bacteria in the intestines but also causing stomach upset when taken in large quantities.

Yacon syrup has a molasses-like consistency with a flavor similar to figs or raisins. It can be used as a lower calorie substitute for sugar since it has 7 calories per teaspoon (regular table sugar has 15).

Proponents recommend consuming a teaspoon of yacon syrup before each meal to help promote weight loss. Its high fiber content is believed to help increase satiety, making you feel full longer. One small study published in 2009 found a desirable effect for weight loss and insulin levels for women who took a daily dose of yacon syrup for 120 days. (Yacon syrup sells online for about $2.85 per ounce. So using 3 teaspoons a day would cost about $43.00 per month.)

Bottom Line: When it comes to weight loss, there's still no magic pill -- or syrup for that matter. At this point there’s not enough research to say whether or not yacon syrup can really help with weight loss. If you like the taste and don't experience any unpleasant side effects, you could add it to your arsenal of lower calorie sweeteners.

Dana Angelo White, MS, RD, ATC, is a registered dietitian, certified athletic trainer and owner of Dana White Nutrition, Inc., which specializes in culinary and sports nutrition. See Dana's full bio »