A Randomized Trial of a Low-Carbohydrate Diet vs Orlistat Plus a Low-Fat Diet for Weight Loss
Background Two potent weight loss therapies, a low-carbohydrate, ketogenic diet (LCKD) and orlistat therapy combined with a low-fat diet (O + LFD), are available to the public but, to our knowledge, have never been compared.
Methods Overweight or obese outpatients (n = 146) from the Department of Veterans Affairs primary care clinics in Durham, North Carolina, were randomized to either LCKD instruction (initially, <20 g of carbohydrate daily) or orlistat therapy, 120 mg orally 3 times daily, plus low-fat diet instruction (<30% energy from fat, 500-1000 kcal/d deficit) delivered at group meetings over 48 weeks. Main outcome measures were body weight, blood pressure, fasting serum lipid, and glycemic parameters.
Results The mean age was 52 years and mean body mass index was 39.3 (calculated as weight in kilograms divided by height in meters squared); 72% were men, 55% were black, and 32% had type 2 diabetes mellitus. Of the study participants, 57 of the LCKD group (79%) and 65 of the O + LFD group (88%) completed measurements at 48 weeks. Weight loss was similar for the LCKD (expected mean change, –9.5%) and the O + LFD (–8.5%) (P = .60 for comparison) groups. The LCKD had a more beneficial impact than O + LFD on systolic (–5.9 vs 1.5 mm Hg) and diastolic (–4.5 vs 0.4 mm Hg) blood pressures (P < .001 for both comparisons). High-density lipoprotein cholesterol and triglyceride levels improved similarly within both groups. Low-density lipoprotein cholesterol levels improved within the O + LFD group only, whereas glucose, insulin, and hemoglobin A1c levels improved within the LCKD group only; comparisons between groups, however, were not statistically significant.
Conclusion In a sample of medical outpatients, an LCKD led to similar improvements as O + LFD for weight, serum lipid, and glycemic parameters and was more effective for lowering blood pressure.
Here is some commentary on the study:
Weight loss was the same and blood pressure control was more effective with a low-carbohydrate diet than a low-fat regimen supplemented by the diet drug orlistat (Xenical, Alli), a randomized trial found.
Among 146 overweight or obese outpatients, both treatment plans led to weight loss of about 10% after 48 weeks, with similar improvements in glycemic and blood lipid measures, according to William S. Yancy Jr., MD, MHS, of Duke University, and colleagues.
But mean systolic and diastolic blood pressure declined by 5.9 and 4.5 mm Hg, respectively, in the low-carb diet compared with a slight increase in patients on the low-fat diet plus orlistat, the researchers reported in the Jan. 25 issue of Archives of Internal Medicine.