If you are one of the thousands of people trying to lose weight, you may be interested in the results of a new study which suggests low-carb dieting may produce heart-healthier weight loss than low-fat dieting. If its findings are indeed replicated by future research, they could have highly-important implications, as the American Heart Association has promoted the low fat diet for years as the heart-healthiest way to manage weight and cardiovascular risk.
A team of researchers compared the outcomes of 307 obese individuals (average BMI= 36) assigned either a low-carb diet or a low-fat diet over 2 years. Both groups also participated in a group lifestyle modification program led by a health professional, which included initiating a walking program, maintaining food and exercise records and learning skills to manage eating behaviors. The average age of participants was 45.5 years, and no participants had diabetes, high blood pressure or pre-existing high cholesterol or triglyceride levels.
The low-carb group followed a program based similar to Dr. Atkins’ New Diet Revolution. Carbohydrate intake was restricted to 20 grams per day for 3 months, followed by a 5 gram per day increase each week until the goal weight was attained. In the beginning of the diet, carbohydrates came from non-starchy vegetables, such as lettuce, broccoli, and cucumbers. Participants could eat as many foods rich in fat and protein as satisfied them. The low-fat group was instructed to restrict the number of calories consumed to 1200 to 1500 calories per day for women and 1500 to 1800 calories per day for men, and the amount of calories from fat could not exceed 30% of total calories. Additionally, both groups were provided with a multivitamin to help prevent possible nutritional gaps.
At the end of 2 years, both groups lost about 7% of their initial body weight. At various points during the study, the low-fat group had lower LDL “bad” cholesterol and the low-carb group had lower triglyceride levels. In the end however, the only difference was a greater increase in HDL “good” cholesterol among the low-carb group. High HDL levels have been shown to be protective against cardiovascular disease, since HDL helps remove cholesterol from the bloodstream by transporting it to the liver. Although HDL levels were higher in the low-carb group, it is important to note that both groups had an improved cardiovascular profile overall and lost comparable amounts of weight.
However, both groups experienced high drop-out rates over the course of the study, which is consistent with the difficulty of maintaining long-term dietary and lifestyle change commonly seen in the general population.
Since a low-carb diet emphasizes protein and fat, it is imperative to take into account the type of fat consumed when following this diet. The majority of fats should come from unsaturated sources, such as:
- Nuts and seeds
- Low-fat dairy
- Chicken and turkey (without skin)
- Olive, canola, and sunflower oils
Saturated and trans fats have been known to increase LDL and should be avoided. They are highest in:
- Whole fat dairy
- Butter, Lard and Coconut or Palm Oils
- Partially hydrogenated oils (found mainly in margarine, shortening and commercially-baked goods)
- Fried foods, especially fast-food
Whatever diet approach you choose, be sure that it is healthy and manageable enough to make into a lifestyle; something with which you can stick. As this study showed, it would appear to be helpful to seek out support from a group and/or a registered dietitian to help you stick with your program over the longer-term. And as with any drastic dietary change you may be considering, consult your physician or a registered dietitian before moving forward to make sure it’s a safe choice for you based on your individual health history.