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 A(1c) 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. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00108524.

Conjugated linoleic acid supplementation for twelve weeks increases lean body mass in obese humans.

Conjugated linoleic acid (CLA) alters body composition in animal models, but few studies have examined the effects of CLA supplementation on body composition and clinical safety measures in obese humans. In the present study, we performed a randomized, double-blind, placebo-controlled trial to examine the changes in body composition and clinical laboratory values following CLA (50:50 ratio of cis-9, trans-11 and trans-10, cis-12 isomers) supplementation for 12 wk in otherwise healthy obese humans. Forty-eight participants (13 males and 35 females) were randomized to receive placebo (8 g safflower oil/d), 3.2 g/d CLA, or 6.4 g/d CLA for 12 wk. Changes in body fat mass and lean body mass were determined by dual-energy X-ray absorptiometry. Resting energy expenditure was assessed by indirect calorimetry. Clinical laboratory values and adverse-event reporting were used to monitor safety. Lean body mass increased by 0.64 kg in the 6.4 g/d CLA group (P < 0.05) after 12 wk of intervention. Significant decreases in serum HDL-cholesterol and sodium, hemoglobin, and hematocrit, and significant increases in serum alkaline phosphatase, C-reactive protein, and IL-6, and white blood cells occurred in the 6.4 g/d CLA group, although all values remained within normal limits. The intervention was well tolerated and no severe adverse events were reported, although mild gastrointestinal adverse events were reported in all treatment groups. In conclusion, whereas CLA may increase lean body mass in obese humans, it may also increase markers of inflammation in the short term.

A low-carbohydrate, ketogenic diet to treat type 2 diabetes.

BACKGROUND: The low-carbohydrate, ketogenic diet (LCKD) may be effective for improving glycemia and reducing medications in patients with type 2 diabetes. METHODS: From an outpatient clinic, we recruited 28 overweight participants with type 2 diabetes for a 16-week single-arm pilot diet intervention trial. We provided LCKD counseling, with an initial goal of <20 g carbohydrate/day, while reducing diabetes medication dosages at diet initiation. Participants returned every other week for measurements, counseling, and further medication adjustment. The primary outcome was hemoglobin A1c. RESULTS: Twenty-one of the 28 participants who were enrolled completed the study. Twenty participants were men; 13 were White, 8 were African-American. The mean [+/- SD] age was 56.0 +/- 7.9 years and BMI was 42.2 +/- 5.8 kg/m2. Hemoglobin A1c decreased by 16% from 7.5 +/- 1.4% to 6.3 +/- 1.0% (p < 0.001) from baseline to week 16. Diabetes medications were discontinued in 7 participants, reduced in 10 participants, and unchanged in 4 participants. The mean body weight decreased by 6.6% from 131.4 +/- 18.3 kg to 122.7 +/- 18.9 kg (p < 0.001). In linear regression analyses, weight change at 16 weeks did not predict change in hemoglobin A1c. Fasting serum triglyceride decreased 42% from 2.69 +/- 2.87 mmol/L to 1.57 +/- 1.38 mmol/L (p = 0.001) while other serum lipid measurements did not change significantly. CONCLUSION: The LCKD improved glycemic control in patients with type 2 diabetes such that diabetes medications were discontinued or reduced in most participants. Because the LCKD can be very effective at lowering blood glucose, patients on diabetes medication who use this diet should be under close medical supervision or capable of adjusting their medication.