Is Low Fat Really Better Than Low Carb?

In the ongoing debate between low fat versus low carbohydrate, it looks like low carb is pulling ahead. Both are comparable at shedding pounds. But the claim that low-carb diets may lead to an elevated risk of heart disease is false.  According to a recent study published in the Annals of Internal Medicine, low-carb diets may actually reduce cardiac risk factors.

Low-carb diets have been popular for years. Previous studies reported that they led to more early weight loss than low-fat diets. However, the results after one year are mixed. Previous studies of the two diet types haven’t included comprehensive behavioral support programs that could improve long-term results.

The study tracked 307 people with a body-mass index (BMI) of 30-40, considered obese. Normal BMI is 18.5- 24.9, overweight is 25-29.9, and obese is 30 and over. Researchers wanted to compare weight loss after two years on a low-carb diet versus a low-fat diet when both are combined with a comprehensive behavioral support program.

Patients were assigned to either a low-carb or low-fat diet. The low-carb group was instructed to eat no more than 20 grams of carbohydrate per day for three months, then increase carbohydrate intake gradually until they achieved their desired weight.  A low-carb diet allowed only low-glycemic index vegetables but with unrestricted consumption of fat and protein.

The low-fat group was instructed to decrease daily intake to between 1200 and 1800 calories per day with no more than 30% of calories from fat. All patients participated in educational programs about changing physical activity and other lifestyle factors. The program was conducted weekly for 20 weeks, then every other week of 20 weeks, then monthly for the rest of the two-year study.

After two years, patients lost an average of 7% of body weight in both groups. Think about that: The low carb group had unrestricted access to fat and protein foods but still lost as much as the calorie- and fat-restricted diet. In addition, the low-carb group improved their heart health during the second year.

During the first six months, the low-carb group had greater reductions in blood pressure, triglycerides and a certain type of LDL cholesterol. The group also had greater increases in HDL (“good”) cholesterol, rising about 23% at the two-year mark.

The study shows that a behavioral support program is key to a sustained weight-loss program. Low-carb diets offer some benefits over low-fat diets in terms of reduction of cardiac risk factors. It’s unclear if such diets are sustainable long term and if they’d actually reduce the incidence of heart disease.

Tell Us!
Do you follow a low-carb or low-fat diet?