Watching Your Weight? You Might Want to Turn to This Unexpectedly Fat-Rich Food

Walnuts are nutritional powerhouses, loaded with antioxidants and omega-3 fatty acids. Eating 14 walnut halves a day for a few months can help blast belly fat, according to a study published in the Nutrition Journal. It can also lower the levels of blood fats (triglycerides) and raise good cholesterol, HDL, which is good for your heart. Another perk: Walnuts, with their anti-inflammatory properties, can protect against certain types of cancers.

A study in the International Journal of Obesity found that a quarter-cup of almonds--along with a diet rich in fruits and veggies--helped overweight and obese adults shed pounds after just two weeks. Those who kept noshing on these nuts for 24 weeks reduced their weight and BMI by a whopping 62 percent. Almonds, high in fiber, can also boost the good bacteria in your gut, which aids in digestion and regularity.

Pistachios are known as the skinniest of nuts: 50 pistachios contain 160 cals and 14 grams fat. Researchers at UCLA studied two groups of people who were on a low-calorie diet: one group snacked on pistachios, the other on pretzels. After a month, the pistachio-eaters had shaved a point off their BMI--and lowered their cholesterol levels too.

Just two Brazil nuts give you the daily amount of selenium your body needs to keep your thyroid functioning. Lower levels of the mineral means your thyroid has a tougher time making the hormone it needs to regulate your metabolism, and that can make it harder for the body to burn calories. Brazil nuts are also rich in antioxidants as well as vitamin E, which can boost your immune system too.

We tend to think of peanuts as bar food, or the munchie of choice at baseball games. But peanuts are high in antioxidants--as high as strawberries and blackberries. What do antioxidants have to do with weight? They protect the body from inflammation, which can cause damage to our cells. If our cells are healthy, they're more efficient in doing what they need to do, including boosting our metabolism so our bodies are faster at converting food into energy.

Hazelnuts come from the same family as walnuts, so they have similar weight-loss properties. They are high in monounsaturated fats, which can help manage blood sugar and lower your chance of developing type 2 diabetes. They're also rich in vitamin E, which can protect your eyes against cataracts and macular degeneration.

Although they're high in calories, macadamia nuts are the richest in the good type of fat. A University of Pennsylvania study found that adding these nuts to your diet could lower your cholesterol and triglyceride levels, both of which contribute to weight gain (especially the fat accumulated in your abdomen).