• Mayo Clinic Minute: Which sugars won’t pack on pounds

Not all sugars are created equal.

"The real sugar we should worry about is added sugars," says Dr. Donald Hensrud, who heads up the Mayo Clinic Healthy Living Program and is the author of The Mayo Clinic Diet.

Watch: The Mayo Clinic Minute

Journalists: Broadcast-quality video pkg (0:58) is in the downloads. Read the script.

Dr. Hensrud says added sugars account for a big portion of calories in most people's diets and are one of the main causes of weight gain.

But there are sweet treats that don't have any added sugars: fruit.

"It gets a reputation of being high in sugar, but a small piece of fruit is only about 60 calories," he says. "There's a lot of water. There's other nutrients. There's fiber. So there [are] many other beneficial things in fruit."

Not only will sugar from fruit not cause you to gain weight, it likely does the opposite.

"Studies have shown when people increase their fruit and vegetable intake, their overall risk of gaining weight decreases because they're not eating something else that's higher in calories," Dr. Hensrud says.

So having a sweet tooth doesn't have to be a bad thing. Just make sure you're picking the right sweets with the right kind of sugars.