Think artificial sweeteners are a surefire shortcut to a slim waist? Think again. Unless you or your kids have diabetes, it's better to choose a healthy diet – including small amounts of regular sugar – than to load up on sweeteners. The reason: sweeteners may actually cause people to overindulge in high-calorie foods, according to one U.S. study. And even though they've been approved by the Food and Drug Administration (FDA), many artificial sweeteners are so new that researchers haven't determined their long-term effects.

That said, it's pretty hard to avoid sweeteners because they're added to everything from diet soft drinks to prescription medications. Here's what you need to know to choose wisely.

Sucralose (Splenda)

Found in low-carb products, diet soft drinks, gelatin, light fruit beverages and low-cal baked goods.

What is it?
Regular sugar (sucrose) bonded to chlorine.

How safe is it?
Safe. “The toxicological tests have shown that the chlorine in sucralose is perfectly harmless,” says Manfred Kroger, a sweetener expert for the Institute of Food Technologists and professor of food science emeritus at Pennsylvania State University .

Aspartame (NutraSweet, Equal)

Found in diet soft drinks, low-cal products and sugar-free candy and gum.

What is it?
A combination of amino acids.

How safe is it?
Safe. Aspartame has never been proven to increase the risk of cancer, but rare cases of seizures, headaches, dizziness and a worsening of depression have been cited in those who ingest large amounts (more than 20 cans of diet soda a day). But these symptoms are extremely natural, says Kroger. Everyone reacts to various chemicals differently. Just like some people will get a headache from inhaling coffee fumes, others may develop similar symptoms from ingesting aspartame. The bottom line: “Aspartame is perfectly safe,” he says. “It has gone through approval processes. It has been reexamined, the critics have been answered and reanswered again.”