SEATTLE, Wash. -

This is the year you’ve vowed to finally shed that extra weight! But you might be making poor choices without even knowing it.  What you think is good for you, may not be good at all.

One common mistake: going gluten-free.

“There’s really nothing to do with weight loss when we talk about gluten.”explained Judy Simon, MS, RD, Clinical Dietitian at the University of Washington Medical Center.

Simon says gluten-free dieters often lose weight because they consume fewer calories and carbs – not because they cut gluten.

Another culprit: healthy drinks – like vitamin water.

“You’re kind of drinking sugar water, and you’re spending a lot of money on it,” Simon said.

Also beware of snacks labeled “low fat” – like a bag of Chex Mix.

“The claim on it is it has 50 percent less fat than potato chips,” Simon said.

But when you compare it to a bag of plain chips – it actually has more than twice the calories.

“Low sugar” ice cream can be another trap. One brand has 100 calories per serving – the same as regular ice cream – but it has more artificial flavors and ingredients.

“What I tell people is if you want to enjoy a dessert, you’d probably do better with a smaller portion of the real thing,” Simon said.

Low-fat salad dressings are often loaded with hidden sugars; one of these has eight grams per two tablespoons. That’s like tossing 10 jelly beans in your salad! And one brand of low-fat cottage cheese has 400 milligrams of sodium per serving. That’s like eating more than two, one ounce bags of potato chips!

Another diet food to watch out for: fast food salads. You might think you’re being healthy, but these are often very high in calories and sodium. A McDonald’s Caesar salad with grilled chicken contains more than half the recommended amount of sodium, and that’s without the dressing. The worst part is usually the chicken, which is often cooked in a high-sodium marinade and injected with a sodium solution to keep it moist.

The bottom line?

“Just because it has a health claim, doesn’t mean it doesn’t have calories,” Simon said.

Advice that could make this year’s weight loss plan a success.