Including walnuts in your daily diet can lower your cholesterol levels and help you lose weight. A study published in the Journal of the American Heart Association found that walnuts contain heart-healthy polyunsaturated fats, and can have weight loss effects similar to a diet that's lower in fat and higher in carbohydrates.

"One of the surprising findings of this study was that even though walnuts are higher in fat and calories, the walnut-rich diet was associated with the same degree of weight loss as a lower fat diet," said lead researcher Dr. Cheryl Rock of the University of California, San Diego School of Medicine.

For their study, researchers enrolled 245 overweight and obese women ages 22 to 72. They assigned women to one of three diets: a lower fat and higher carbohydrate diet, a lower carbohydrate and higher-fat diet, or a walnut-rich, higher-fat and lower-carbohydrate diet.
Those prescribed a diet rich in walnuts ate 1.5 ounces (about three tablespoons) of walnuts each day.

While weight loss was comparable in all three groups — about 8 percent of their original weight — those in the walnut-enriched group exhibited the most improvement in cholesterol levels, especially in those who were insulin-resistant. In addition to a significant decrease in LDL cholesterol, those in the walnut group experienced a greater increase in HDL (good) cholesterol in comparison to the other diet groups.

"Considering the results of this study, as well as previous walnut research on heart health and weight, there's something to be said for eating a handful of walnuts a day," said Dr. Rock.

Other studies have also found walnuts to be heart healthy. A study from Penn State speculated that the healthy compound was alpha-linolenic acid, a type of omega-3 fatty acid found in plants.