[Note: The ketogenic “Atkins-type” diet used in this trial is high-fat, adequate-protein, low-carb. It is called ketogenic because it forces the body to burn fats rather than carbs for energy. While carbs are converted into glucose for energy, fats are converted by the liver into fatty acids and “ketone bodies,” which replace glucose as an energy source. Orlistat is a prescription drug that acts to limit the digestive tract’s ability to digest and absorb fats consumed in the diet.]
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, less than 20 grams of carbohydrate daily) or orlistat therapy, 120 mg orally 3 times daily, plus low-fat diet instruction (less than 30% energy from fat, 500 to 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 low-carbohydrate, ketogenic diet (expected mean change, –9.5%) and the orlistat plus low-fat diet (–8.5%) (P = .60 for comparison) groups.
• The low-carbohydrate, ketogenic diet had a more beneficial impact than orlistat plus low-fat diet 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 [so-called ‘good’] cholesterol and triglyceride levels improved similarly within both groups.
• Low-density lipoprotein [so-called ‘bad’] cholesterol levels improved within the orlistat plus low-fat diet group only,
• Whereas glucose, insulin, and hemoglobin A1c levels improved within the low-carbohydrate, ketogenic diet group only; comparisons between groups, however, were not statistically significant.
Conclusion: In a sample of medical outpatients, a low-carbohydrate, ketogenic diet led to similar improvements as orlistat plus low-fat diet for weight, serum lipid, and glycemic parameters and was more effective for lowering blood pressure.
Trial Registration: clinicaltrials.gov Identifier: NCT00108524
Source: Archives of Internal Medicine, Jan 25, 2010;170(2):136-145. PMID: 20101008, by Yancy WS, Westman EC, McDuffie JR, Grambow SC, Jeffreys AS, Bolton J, Chalecki A, Oddone EZ. Center for Health Services Research in Primary Care, Department of Veterans Affairs Medical Center; Departments of Medicine and Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina, USA. [E-mail: yancy006@mc.duke.edu]
