When you’re trying to eat right, there are a lot of obvious nutritional potholes to avoid. Packaged donuts. French fries. White bread. You might miss them, but you know it’s worth it to steer clear. It’s even more of a bummer to learn that some of the things you thought were good for you (or at least OK for you) are actually sabotaging your efforts.Too much added sugar or added syrup (that is, added to foods rather than part of them) is bad for your body—and bad for your beauty, too. Sugar is quickly absorbed, and high levels of sugar in your blood can hamper the function of important proteins—for example, making hemoglobin unable to properly deliver oxygen to your tissues. Further, if you eat too much sugar and produce too much fat from that, your body can build up what’s called insulin resistance, which is one step away from type 2 diabetes. High blood sugar also disrupts the lining of your arteries and causes dangerous inflammation.MORE: The Anti-Inflammatory Diet for BeginnersBecause excess added sugars, syrups and non-100 percent whole grains are stored as fat, they are a major enemy to maintaining a healthy weight. Meanwhile, sugar damages the fibers that keep your skin supple and smooth, contributing to signs of aging like wrinkles and sagging. Not pretty!As a general rule of thumb, whatever you eat should have no more than four grams of added sugars per serving. But even “healthy” foods often exceed that by a lot. Here are eightn sneaky sources of sugars to keep an eye on:1. Chocolate Milk: 30 grams of sugar per cup2. Energy Bars: 30 to 50 grams of sugar3. Sports Drinks: 55 grams of sugar4. Nonfat Fruit Flavored Yogurt: 47 grams of sugar5. Granola: 14 grams of added sugar in half a cup6. Bottled Fat-Free Salad Dressings: 2 to 6 grams of sugar per two-tablespoon serving (if you’re a heavy salad dresser, you might use more than that)7. Ketchup and Barbeque Sauce: 6 grams of sugar per ounce (about four squeeze-packets’ worth)8. Fruit Juice: 22 to 36 grams of sugar in one cupMORE: Science Explains the Dark Side of JuiceSo what do you do if these undercover sugar agents are common ingredients in your diet? First, look for easy swaps. Add fresh fruit and berries to nonfat no-sugar added Greek yogurt. Make your own salad dressing at home, with extra virgin olive oil (full of healthy and beautifying Omega-9s!), balsamic vinegar or lemon juice, herbs and spices. Opt for a whole fruit smoothie over juice. The dietary fiber from the meat of the fruit, which isn’t present in juice, helps you digest the sugars more slowly.And remember that just because something sounds like it’s a performance enhancer, doesn’t mean it’s all good. A bottle of Gatorade and an energy bar is more sugary than two king-size Snickers! By focusing on fresh, whole foods you can make great tasting choices that keep you more beautiful for the long run, too.QUIZ: Do You Eat for Beauty?