An unfortunate drawback to the popular high−protein, low−carbohydrate diet is that it may increase the LDL form of cholesterol – also known as “bad” cholesterol. Researchers at the University of Colorado found that while the diet is as effective for weight loss as a low−protein, high−carbohydrate diet, it does have the unwanted effect of increasing certain blood fats.
Participants on the low−carb diet showed increases in LDL cholesterol of 12 mg/dl, while the LDL cholesterol of those on the high−carb diet decreased by 7 mg/dl.
Teri L. Hernandez and her colleagues studied the effects of the two diets in 32 obese participants. They randomly assigned half of the subjects to the low−carb diet and half to a high−carb diet, for a period of six weeks. Those on the low−carb diet were instructed to consume 20 grams or fewer of carbohydrates per day, while participants on the high−carb diet took in 55% of their daily calories from carbs.
People in both groups lost about the same amount of weight – on average, about 13 pounds over the six−week period. But changes in their cholesterol levels were very different. Participants on the low−carb diet showed increases in LDL cholesterol of 12 mg/dl, while the LDL cholesterol of those on the high−carb diet decreased by 7 mg/dl. Another effect of the low−carb diet was that the blood levels of free fatty acids increased in this group of participants, whereas this was not true for the high−carb dieters.
The study was published in the January 27, 2010 online issue of the American Journal of Clinical Nutrition.