It may not surprise anyone that a 20-ounce bottle of soda can contain anywhere from 15 to 22 teaspoons of sugar per serving, but sugar is also lurking in less obvious places. The USDA's Dietary Guidelines suggest no more than 10 teaspoons a day of added sugar, but if you're not paying attention, those spoonfuls can add up fast. Here are 5 sources of sugar found in seemingly healthy choices.

Many brands of balsamic vinaigrette have the equivalent of 1 teaspoon of sugar per serving (and a serving is only 2 tablespoons). French and Thousand Island style dressings are just as bad, if not worse. The solution: Make your own.

Many parents hand over these bars to their kids for a quick breakfast or after school snack- but don’t be fooled. Many brands are mini-sized candy bars in disguise. These 2-bite wonders contain 1.5 to 2 teaspoons of sugar per piece. Check ingredient lists and look for one where sugar isn't listed in the top two ingredients.

Toaster tarts and instant flavored oatmeal may seem like healthy grab-and-go options, but each serving offers up 2 to 5 teaspoons of added sugar. Your mornings deserve better! Choose one of these quick breakfasts instead.

They're advertised as must-haves for exercise enthusiasts but the truth is, protein bars can undo all those calories burned by piling on 4 to 7 teaspoons of sugar per serving. Look for bars sweetened with fruit purees and avoid ones that are dipped or drenched in chocolate and other sweet coatings.

There are a lot of different yogurts out there, but on average, an 8-ounce portion of fruit-flavored yogurt packs in 7 teaspoons of sugar. Plain yogurt with fresh fruit (and maybe a light drizzle of honey) is the way to go.

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 »