Gary Foster study: low-carb clobbers low-fat diet on HDL / heart health risk

Filed under: In The News,Study — @ August 3, 2010

Some of the harshest criticism about low-carbohydrate diets such as Atkins has been the supposed negative heart health implications due to elevations that take place in the cholesterol levels of dieters who restrict their carbs in favor of more fat and protein. Additionally, it is presumed that any weight loss that occurs on a high-fat, low-carb diet is quickly gained back making it a uniquely ineffective means for managing weight. Finally, bone health is supposed to suffer for people following a carbohydrate-restricted diet because the higher protein content allegedly promotes bone loss. However, all of these theories about low-carb diets have been summarily shot down by a brand new study funded by the National Institutes of Health (NIH) and published in the August 3, 2010 edition of the medical journal Annals of Internal Medicine.

Lead researcher Gary D. Foster, Ph.D, director of the Center for Obesity Research and Education and professor of Medicine and Public Health at Temple University, and his team of researchers noted that previous studies comparing low-fat diets with low-carb carb diets have failed to take into account the need for behavioral treatment as part of their dietary instruction which has resulted in poor weight loss outcomes. So they embarked on a 2-year randomized trial study of 307 participants placed on either a low-carbohydrate or low-fat diet combined with a “comprehensive lifestyle modification program” that took place in three academic medical centers, including the University of Colorado in Denver, Colorado, Washington University in St. Louis, Missouri, and the University of Pennsylvania in Philadelphia, Pennsylvania. The average age of the study participants was 45 years old with a mean body mass index (BMI) of 36.1. The study participants were split up into one of two diet categories:

LOW-CARBOHYDRATE DIET GROUP (153 participants)
Carbohydrate intake was limited to 20 grams daily with unrestricted consumption of fat and protein during the first 12 weeks of the study. Permissible carbohydrates were limited to mainly low-glycemic index vegetables. Participants were encouraged to eat 4-5 small meals every few hours and to use butter, mayonnaise and vegetable oils instead of margarine and they were discouraged from trying to “do a low-fat version of the program as it will disrupt weight loss.” At the end of the first 12 weeks, study participants were allowed to increase their carbohydrate consumption by 5 grams daily each week in the form of more vegetables, some fruit, and even whole grains and dairy products until their weight became stabilized. The principles outlined in the all-time #1 bestselling low-carb diet book Dr. Atkins’ New Diet Revolution were encouraged, but the study participants were never provided with a copy of the book. They were told to watch their carbohydrate intake primarily while urged to consume foods that are “rich in fat and protein” to satiety. The behavioral modification implemented with this group was “to limit carbohydrate intake.”

LOW-FAT DIET GROUP (154 participants)
Calories were limited to 1200-1500 daily for women and 1500-1800 daily for men with a fat/protein/carbohydrate ratio of 30/15/55. Study participants were strongly encouraged to keep their calorie intake reduced with a specific focus on cutting down on their fat consumption. The behavioral modification implemented with this group was “limiting overall energy intake.”