Low-Carb May Trump Low-Fat in Diet Wars

By Gina Jabbour, MD

When it comes to choosing the best diet for weight loss and a healthy heart, low-carb may beat low-fat, a new study found.

Researchers at Tulane University found that people following a low-carbohydrate diet had significant benefits in terms of weight loss, decrease in fat mass, waist circumference and cholesterol levels compared to a low-fat diet.

"Carbohydrates, in general, are not the kind of neutral dietary component that we thought they were," said Dr. Lydia Bazzano of Tulane University, the study's lead researcher. "[Historically] they were often at the base of the dietary pyramid."

In the NIH-funded study, Bazzano and her colleagues followed 73 people on a low-fat diet and 75 people on a low-carbohydrate diet for one year. During this year, researchers monitored what the participants of the study ate daily, urging the low-carbohydrate group to limit their carbohydrates to less than 40 grams per day and the low-fat group to get less than 30 percent of daily calories from fat and less than 7 percent from saturated fats.

Both groups also received the same dietary tips, including recommendations to eat dietary fibers and to select "healthy" fats over unhealthy ones.

At 12 months, those on the low-carb diet had lost nearly eight pounds more than those on the low-fat diet. Additionally, these dieters fared better on a commonly used measure of heart disease risk known as the Framingham Risk Score.

"Carefully selecting carbs in your diet would be the best take home message," Bazzano said.

Diet and nutrition experts not involved with the study, however, said there could be other differences to consider between these two types of diets - not the least of which is how easy it is to actually stick to these diets.

"There is more to do and think about with a low-fat diet," said Keith Ayoob, registered dietician and associate clinical professor of Albert Einstein College of Medicine in New York. Specifically, he pointed out that with a low-fat diet, there are more distinctions that need to be made between the types of fat consumed, whereas in a low-carbohydrate diet, you largely eliminate that food group. "A low-fat diet appears less restrictive, but it may be more difficult for some people to comply with."

Lead study author Bazzano's impression, on the other hand, was that a low-carbohydrate diet may be harder to stick to. "At the grocery store there is every product in the world that is low fat," she said.

Regardless, both experts agreed choosing a diet to which you can commit is the most important thing.

"A low carbohydrate diet may be better for a jumpstart," Ayoob said, pointing out that most weight loss occurred in the first three months.

Doctor's Take

Clearly, when most people start a diet, they have one thing on their mind - losing the weight. A few of us might also consider the effects that a diet has on our heart health and general wellness.

What this study shows us is that choosing the right diet may help you kill two birds with one stone. And one of those birds is far more dangerous than the other. Heart disease is responsible for one out of every three deaths in the U.S. today, and diet is a big part of our risk. Past research has implicated sugary foods, with a high glycemic index, in increasing heart disease risk. Additionally, studies have found that when it comes to dietary fat, it's really the type of fat rather than the overall amount of fat that will affect your risk for heart disease.

So if you are hoping to make dietary changes that improve your waistline as well as your heart health, low-carb may be the way to go. Of course, it is important to remember that the patients in this study were only followed for one year, so longer term research is needed. More importantly, the healthfulness of a low-carb approach depends on the types of fats you're getting, with a focus on sticking to foods rich in healthy fats such as almonds, avocados and fish, while avoiding foods packed with unhealthy fats such as fried foods and fatty red meat.

As always, in addition to tipping the scale, maintaining a healthy lifestyle with exercise and a diet that can be followed long-term is still key to protecting our hearts.