10 Surprising Foods That May Hamper Weight Loss

1. Reduced-fat peanut butter        

"When food companies take out one ingredient, they usually have to make up for the lost flavor by swapping in something else," says Karen Ansel, RD, co-author of The Calendar Diet: A Month by Month Guide to Losing Weight While Living Your Life.

In this case, the ingredient list more than doubles, the calorie count barely drops, and you get lots of extra sugar and sodium. Instead, Ansel recommends choosing all-natural peanut butter; the only ingredients should be peanuts and perhaps salt.

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2. Gluten-free cookies

Gluten -- a mixture of proteins found in wheat, rye, and barley -- has gotten a bad rap lately, and many people mistakenly think "gluten-free" is code for healthy. Not necessarily.

"Unless you have celiac disease or gluten intolerance, gluten-free foods aren't necessarily better for you," says Lyssie Lakatos, RD, co-author of The Nutrition Twins' Veggie Cure.

3. Fat-free bottled salad dressing

"Many aren't much lower in calories compared to the full-fat versions," says Chicago nutrition consultant Janet Helm, RD.

She adds that people often eat too much of something when it's labeled fat-free. Helm suggests making your own vinaigrette with extra-virgin olive oil.

4. Turkey bacon

It sure sounds healthier, doesn't it? "It is slightly lower in fat and calories than regular bacon," Ansel says, "but it has upwards of 180 milligrams of bloating sodium per slice."

The problem is that turkey bacon falls in the category of "processed meats," which are high in sodium and other food additives that may have health risks. That's why health professionals recommend limiting processed meats like sausage, bacon, and hot dogs in your diet, even when they are marketed as leaner or more natural.

As with other foods, check the label to see what you're getting.

5. Prepared salad kits

Salads are a great idea, but like anything else, the question is: What's in it?

"Many have loads of excess calories and fat from full-fat cheese, oil-soaked croutons, and pouches of dressing," Lakatos says. "Your 'healthy' meal could have more calories than three Hershey's bars."

Craft your own salad from a variety of low-cal veggies, and top with avocado, low-fat cheese, or nuts.

6. Juice ‘drinks’

The word "drink" or "beverage" is usually a signal that it has a mere fraction of real juice. "Check the label, but odds are it's mostly added sugar, natural and artificial flavorings, and water," says Maryann Jacobsen, RD, co-author of Fearless Feeding. Also, you may want to limit even 100% fruit juice, because it's high in natural sugar without the filling fiber found in whole fruits.

7. Premade smoothies

Some bottles can cost you as much as 600-1,000 calories, warns Tammy Lakatos Shames, RD, co-author of The Nutrition Twins' Veggie Cure. "Even if it contains no added sugar, watch out," she says.

8. Sports drinks

If you're really sweating it out for an hour or more, then it makes sense to replenish lost electrolytes. Just spent 30 minutes on the elliptical while reading a magazine? "You barely burned off the 125 calories that are in many 20-ounce bottles," Lakatos Shames says. Stick with calorie-free water.

9. Bottled iced tea

"Tea is packed with antioxidants, but when you buy it bottled you usually get more sugar water than anything else," Lakatos Shames says. Making your own unsweetened tea is an easy way to save 150-200 calories.

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10. Nonstick cooking spray

It may not be saving you calories. "Each 1-second spray only contains about six calories, but who only spritzes for a second?" Ansel says.

She suggests swapping it for a small amount of olive oil. Yes, it has a few more calories, but you'll also get heart-healthy polyphenols and more flavor, so you may end up eating less food overall.