A new randomized study comparing 1) a low-carbohydrate diet with 2) combination of weight-loss drug, orlistat (Xenical), and a low-fat diet has found that both strategies produced similar weight loss over a one-year period. The low-carb diet, however, also produced a significant improvement in blood pressure.

The study, published in the January 25, 2010 issue of the Archives of Internal Medicine, randomized 146 obese outpatients to either 1) a low-carbohydrate, ketogenic diet or 2) to orlistat (120 mg, three times daily) and a low-fat diet for over 48 weeks. At the end of the study period, both strategies resulted in similar weight loss (10% or 20 to 25 pounds).

HDL and triglycerides improvements were seen in both groups, LDL levels improvement was seen in the orlistat/low-fat diet group only while glucose, insulin, and HbA1c levels improvements were seen only in the low-carb group, although none of the differences were statistically meaningful.

By contrast, patients in the low-carb group experienced a significant decrease in both systolic and diastolic blood-pressure levels when compared with the orlistat/low-fat diet group.

Implications: This study did not suggest one diet is better than the other one. It only provides another option, low-carb option, for those who want to lower their weight as well as their blood pressure.

* Orlistat is not associated with increases in blood pressure, but other diet drug such as sibutramine (Meridia), has recently released an updated warning on its contraindication in patients with cardiovascular disease.