Low-carbohydrate diets were initially popularized by the late Dr. Robert Atkins, who published the fundamentals of this diet in his book Dr. Atkins’ New Diet Revolution. He also founded Atkins Nutritional to commercialize and further evangelize the low-carbohydrate diet. Following Dr. Atkins’s death, however, the popularity of the diet subsided and his company filed for Chapter 11 bankruptcy in 2005.
Despite its controversial nature, the low-carbohydrate diet may still have health benefits. A group at the Center for Health Services Research in Primary Care, Department of Veterans Affairs Medical Center (Durham, North Carolina), recently published their findings in the Archives of Internal Medicine, where they compared the low-carbohydrate, ketogenic diet (LCKD) with a low-fat diet (combined with the weight-loss medication orlistat) regarding their effects on several health parameters: weight loss, blood pressure, cholesterol levels, and glycemic parameters.
The study recruited 146 overweight or obese patients and randomized them to either the LCKD or low-fat diet. The LCKD consisted of a daily carbohydrate limit of 20 g. The participants could also eat unlimited meat and eggs, 112 g of hard cheese, 0.48 L of low-carbohydrate vegetables, and 0.24 L of moderate-carbohydrate vegetables everyday. The low-fat diet included consumption of <30% of energy from fat with a 500-1000 kilocalorie/day deficit (calculated from the intake necessary to maintain weight). The latter group also took 120 mg of orlistat before meals 3 times daily throughout the study duration of 48 weeks.
The study revealed that weight loss was similar for the LCKD and orlistat/low-fat diet groups. The mean weight change was -11.4 kg (-9.5%) and -9.6 kg (-8.5%), respectively. Over the first 36 weeks, changes in lipid profile were different among the two diets: the LCKD had better high-density lipoprotein (HDL) cholesterol and triglyceride levels, while the orlistat/low-fat diet had better low-density lipoprotein (LDL) cholesterol levels. But by the 48 weeks, there were no differences in improvement among the diets. For glycemic parameters, the LCKD participants experienced significant decreases in fasting glucose levels (-9.7 mg/dL), fasting insulin level (-7.3 microIU/mL), and hemoglobin A1c (-0.3%). The LCKD group also had better improvements in systolic (-5.9 mmHg) and diastolic (-4.5 mmHg) blood pressures.
Adverse effects from the diets were recorded. Compared to the orlistat/low-fat diet group, the LCKD group reported more constipation, increased urinary frequency, halitosis, and leg muscle cramps. The orlistat and low-fat diet group reported more flatus, bowel incontinence, and diarrhea.
The authors conclude that “the LCKD and the [oristat and low-fat diet] were equally effective for weight loss and severe cardiovascular disease risk factors, although the low-carbohydrate diet was more effective for lowering blood pressure.” While the study does not measure long-term adverse effects of either diet, it shows that the low-carbohydrate diet is a suitable non-pharmacologic method for weight loss. And unlike the low-fat diet, it does not have a daily calorie restriction, so one can eat to the heart’s — or stomach’s — content.
- Source
- Yancy WS Jr, Westman EC, McDuffie JR, Grambow SC, Jeffreys AS, Bolton J, Chalecki A, Oddone EZ. A randomized trial of a low-carbohydrate diet vs orlistat plus a low-fat diet for weight loss. Arch Intern Med 2010;170:136-45.
