A recent clinical trial compared a low-carb diet with a low-fat diet and supports other research that has found that these two diet approaches result in similar weight loss after two years. In this trial, 307 overweight and obese participants were randomly assigned to one of the two diets: the low fat diet restricted calories to 1200-1500 and 1500 to 1800 calories for women and men respectively. The diet included about 55% carbohydrate, 30% fat and 15% protein. The low carbohydrate diet restricted carbohydrates to 20 grams a day for 12 weeks, then increased to a more reasonable level during the duration of the diet interventions. They were allowed to eat as much fat and protein as they wanted.
The participants weighed at the start an average of 227 pounds with a mean body mass index of 36. At one year the average weight loss was 24 pounds, but after two years decreased to 15 pounds due to participants gaining back some of the lost weight.
But wait, diets should not be just about weight loss. There were differences in health benefits between these two weight loss approaches. First of all, the low-carb diet lowered blood pressure, triglycerides and VLDL cholesterol early in the study, which evened out with both diets after two years. However, the big payoff was that HDL cholesterol (healthy) increased considerably in the low carb diet versus the low fat. After two years, the increase was 23% in the low-carb group compared to 12% in the low-fat group. Also after two years, total cholesterol was reduced slightly in the low-carb group. Other recent research suggests to further boost the heart benefits is to substitute some of the meat protein in a lower-carb diet with some vegetable protein.
On a personal note: When I began a carbohydrate-restricted diet a couple of years ago, my “good” HDL cholesterol increased from a respectable level in the low 60 mg/dl range to an astounding 90 mg/dl range after 6 months and remains there. In addition, my triglycerides were cut in half. I was impressed as well as my doctor.
Please consult your doctor before trying any new dietary approach – one diet does not fit all. Your diagnoses, and entire lipid profile should be assessed carefully before any drastic diet changes are undertaken.