Researchers from of the Center for Obesity Research and Education at Temple University, Philadelphia have revealed that after a two-year comparison, a low-carb diet fares about as well as a low-fat diet with regards to weight loss, but low-carb improves cardiovascular risk factors more.

The study, published in the peer-reviewed medical journal Annals of Internal Medicine, explained that cardiovascular risk factors, such as blood pressure and lipid (cholesterol) levels responded better with the low-carb diet. Both diets produce identical weight loss when coupled with comprehensive behavior treatment

Put simply – it appears that both diets are equally good for losing weight, but the low-carb diet protects you from potential coronary heart diseases more effectively.

The findings may come as a surprise to many people who instinctively link low-carb with worsening cardiovascular risk factors.

Three hundred and seven patients were randomly assigned to either a low-carbohydrate (n=153) or low-fat (n=154) diet with behavior treatment. Weight at two years was the primary outcome, but other effects were measured throughout the study period.

At 3, 6 and 12 months, the participants were evaluated for:

  • Weight
  • Serum lipid concentrations
  • Blood pressure
  • Urinary ketones
  • Bone mineral density
  • Body composition

Among the participants in the two diet groups, the researchers found:

  • Weight – no differences at any point during the study. About 7% loss of weight at two years in both groups.
  • Body composition – no differences at any point during the study
  • Bone mineral density – no differences at any point during the study
  • Good cholesterol levels – double the increase among the low-carb group compared to the low-fat group at two years. 23% and 11% respectively.

Gary Foster, PhD, director of the Center for Obesity Research and Education at Temple University, Philadelphia, said:

I think an important outcome from a study like this is to think about which diets fit best for which people. This study would suggest that perhaps for those with low HDL-cholesterol levels to begin with, that a low-carbohydrate approach to weigh loss may have some dvantages.

Foster added:

“At the end of the day, behavior interventions are key. Dieters should be less concerned about what diet they follow, and more concerned with employing effective behavioral strategies, such as recording what they eat, logging their exercise, and limiting the triggers for overeating, like watching TV or eating in the car.

“Weight and Metabolic Outcomes After 2 Years on a Low-Carbohydrate Versus Low-Fat Diet – A Randomized Trial”
Gary D. Foster, PhD, Holly R. Wyatt, MD, James O. Hill, PhD, Angela P. Makris, PhD, RD, Diane L. Rosenbaum, BA, Carrie Brill, BS, Richard I. Stein, PhD, B. Selma Mohammed, MD, PhD, Bernard Miller, MD, Daniel J. Rader, MD, Babette Zemel, PhD, Thomas A. Wadden, PhD, Thomas Tenhave, PhD, Craig W. Newcomb, MS, Samuel Klein, MD
Annals of Internal Medicine August 3, 2010 vol. 153 no. 3 147-157

Written by Christian Nordqvist