The Study

A low carbohydrate (carb) diet can reduce body weight and some cardiovascular disease (CVD) risk factors as compared to a low fat diet, but differential adherence may play a role. The study therefore looked at the ability of participants to follow the set dietary goals and the resulting impact on weight loss and improvement in body composition over one year.

Methods

The study compared indicators of dietary adherence between two dietary interventions and examined their relationship with dietary efficacy using data from 148 obese adults (Mean age, 47 y; Mean body mass index, 35.4 kg/m2; 11.5% men; 51% Black) who participated in a randomized controlled trial comparing the effect of a low carb diet (net carb<40 g/day) with a low fat diet (<30% energy from fat, <10% from saturated fat) on changes in weight and CVD risk factors.

Results

There was no significant difference in the attendance at dietary counseling sessions between the groups (56.7% low carb group vs. 52.3% low fat group).

In the low carb group, 45% of individuals met the carbohydrate goal while 55% were above, with a mean of 198% deviation representing a carb intake of approximately 119 grams. In the low fat group, 56% and 28% of individuals met total and saturated fat goals, and those who were above had mean deviations of 23% and 46%, representing intakes of about 37% and 10% of energy from total and saturated fat, respectively.

At 12 months, the low carb group had a higher cumulative percentage of ketones detected in urine, compared to the low fat group (25% vs. 8%, P<0.001). There was no significant difference in composite scores for adherence between the groups [Mean (SD): 64 (19) low carb vs. 61 (20) low fat].

Conclusion 

In the low carb group, attendance at more dietary sessions, less deviation from carb goals and presence of urinary ketones were consistently associated with reductions in body weight and fat mass and increase in lean mass.

Importantly, “indicators of adherence to a low carb diet were not associated with blood pressure, lipids, glucose or C-reactive protein.”

The authors conclude that “despite similar adherence between the low carb and low fat diets, adherence to the low carb diet resulted in greater weight loss and better improvement in body composition at 12 months.”

Citation

Hu T, Stuchlik P, Yao L et al Circulation. 2015;131:AMP26