A new study shows that, over the course of a year, a low-carb diet is more effective for weight loss and heart health than a low-fat regimen.

If you’re looking to trim the fat, you might be better off cutting back on carbs than loading up your shopping cart with low-fat foods, according to a recent study. A low-carb diet could also net you a bigger drop in your risk of heart disease and stroke.

The study, published today in the Annals of Internal Medicine, followed 148 clinically obese people for one year as they tried to shed the extra pounds using either a low-fat or low-carbohydrate diet.

By the end of the year, people who had limited their intake of carbs — from breads, cookies, pasta, and other sources — to less than 40 grams a day lost an average of 7 pounds more than people in the low-fat diet group. Limiting carbohydrates also had the added benefit of improving several risk factors for heart disease, including increasing HDL, or “good,” cholesterol and reducing triglyceride levels in the blood.

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At the start of the study, participants were randomly assigned to one of the two diets. To help them stick to their diet, the subjects attended individual and group counseling sessions throughout the year. They were given a handbook filled with recipes, sample menus, food lists, and meal planning advice.

Unlike previous studies, this one included a larger number of African-Americans, who saw just as many benefits as their white peers. It also excluded people with a previous history of heart disease and diabetes, both of which are linked to obesity.

The researchers don’t know exactly why the low-carb group was more successful than the low-fat group. It may be the result of a bigger effect on their resting and overall metabolism, as well as a greater loss of fat in this group.

However, low-carb diets are nothing new. They have become a popular weight loss strategy, especially because more than one-third of U.S. adults are obese. Obesity cost the country $147 billion in medical expenses in 2008 alone, according to the Centers for Disease Control and Prevention.

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Although low-carb diets have been around for some time, their effect on heart health has been a matter of debate, especially since some versions emphasize meat as a low-carb protein source. Meat can also be high in saturated fats, which are not good for the heart. Other research, like a 2008 study published in the New England Journal of Medicine, support the benefits of cutting back on carbs for both weight loss and heart health.

This older study, however, found that low-carb is not the only healthy diet option available. Researchers found that the Mediterranean diet — a vegetable-rich diet with moderate amounts of fat and limited red meat — was also an effective alternative to a low-fat diet for weight loss.

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In spite of the benefits for patients in these types of studies, it is difficult to know whether the gains will last. Some people who lose weight may gain it back later, something a year-long study might miss. The researchers also don’t know whether short-term drops in risk factors for cardiovascular disease will lead to longer-term falls in rates of diseases like heart attacks and stroke.

Because these diet studies tend to be small, the improvements may not apply to the general population. Plus, research participants may have more help, such as regular sessions with a dietitian, than most people who are trying to lose weight. This could have helped keep them on track over the course of year.

While short-term weight loss can affect how you feel about yourself and may improve your heart health, eating well over the long haul can have even more dramatic effects.

According to a recent study in published in JAMA Internal Medicine, the United States seems to be making some progress in this area. Americans are eating less transfats and sugar-sweetened beverages and more whole fruit, whole grains, nuts, and legumes. We still need to eat more vegetables and less red and processed meats.

However, these improvements have occurred mainly among people with higher income levels and more education. Since diet is an important factor in preventing diseases like obesity, Type 2 diabetes, and heart disease, this widening gap in diet quality is a serious challenge for the country as a whole.

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