By Elizabeth Goodman Artis for Shape.com

To snack or not to snack? That depends on the snack. Done the right way (calorie-controlled, nutrient-rich), snacking can keep cravings in check and up the nutritional quality of your diet. But all too often some of the most common snacks—even the ones that seem healthy—are filled with salt, sugar, excess calories, and even harmful chemicals, according to Tiffany Jackson, ND, and Kate Kennedy, RD, practitioners at Cenegenics Carolinas, an age-management medical practice in Charleston, South Carolina. Here, they share the 10 worst snacks for your health:

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  • 1. Canned Peaches

    Canned fruits and veggies may seem like a great snack in a pinch, but not only are canned fruits (particularly the highly popular canned peaches) loaded with excess sugar, their nutrient content is typically much lower than fresh and frozen fruits and vegetables, which are flash frozen at the peak of ripeness. Canned fruit, on the other hand, has had its flavor bolstered by sweeteners so there's no need to use the most flavorful fruit, which is also the most nutrient-dense. Even worse, notes Jackson, the cans are often lined with a toxic chemical that acts as a preservative.

  • 2. Potato Chips

    This is a triple threat snack if there ever was one. Not only are potato chips high in fat, calories, and sodium (threat No. 1), they are a high glycemic vegetable (threat No. 2), which can spike blood sugar. And finally (threat No. 3), when potatoes are heated to a high temperature, they release acrylamide, a harmful chemical associated with nerve damage. And no, you can't eat just one.

  • 3. Rice Cakes

    Rice cakes, while blandly low in calories, are made from processed white rice, which is high in blood-sugar spiking carbohydrates. Plus, many come with flavorings that are loaded with sugar and salt. So even if your net calories are low, munching on these nutrient-void disks is about as healthy (and tasty) as eating Styrofoam packing peanuts.

  • 4. Blueberry Muffins

    Or, as Kennedy calls them, "sugar-laden calorie bombs." This popular muffin's still fools even health savvy people, thanks to its promise of fruit and the fact that, despite the artificial flavorings, added sugars, and ridiculous portion sizes, they just sound wholesome and harmless. Unless you made the muffin yourself, steer clear (and even then it's better as a treat than an everyday snack).

  • 5. Granola Bars

    Part of the problem with granola bars is their sheer ubiquity as an afternoon snack--and the organic promise that is on so many of these bars' labels. Nearly all of them are loaded with processed carbs, dried fruit (which is high in sugar), and held together with even more sugar in the form of honey or even the health-nut favorite agave. Plus, they don't contain much in the way of filling fiber and are often loaded with calories. Save them for the 10-mile hike.

  • 6. Honey-Roasted Salted Nuts

    The combo of sugar, fat, and salt makes these very easy to overeat. While there's also some evidence roasting nuts can deplete them of some of their protein as well, the sugar and salt content outweigh any potential health benefits from the healthy fats many nuts contain.

  • 7. Fat-Free Yogurt With Fruit On The Bottom

    Unlike nonfat Greek yogurt, which has been strained to give it a thick, creamy texture, regular yogurt just becomes watery and bland without the fat. And when they take the fat out, something's gotta go back in. That's usually high-sugar fruit mixture--and a whole lot of it.

  • 8. Microwave Popcorn

    Aside from all the processed carbs and salt, some microwavable popcorn contains highly unhealthy trans fats (for shelf stability). Plus, the insides of the bags are often coated with chemicals to prevent the popcorn from sticking.

  • 9. Dried Fruit

    Would you eat seven mangoes in one sitting? Or 12 peaches? Because dried fruit is pretty much just that. Fruit that has been shrunken down and extracted of its moisture--but the natural sugars remain. As Kennedy notes, our bodies are not equipped to consume that much sugar--even from a natural source--in one sitting.

  • 10. Diet Soda

    Both Kennedy and Jackson agree: Diet soda is the No. 1 worst snack in a can. Why? It contains a <a href="http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/AtHome/aspartame" target="_hplink">potentially carcinogenic </a>chemical, aspartame, which is also linked to neurological issues. Plus, it affects craving centers in the brain, increasing appetite. To top it all off, diet soda is high in phosphorous; calcium and phosphorous need to be in balance to maintain bone health, and if too much phosphorous is present it can leach calcium from your bones.

  • Healthier Snack Options

    Nutritionist Karen Graham gives you great ideas for healthier snacks.

For more on diet and nutrition, click here.