A two-year long comparison of three diets was done in Israel (N Engl J Med 2008; 359:229-241. Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet. Iris Shai, R.D., Ph.D., Dan Schwarzfuchs, M.D., Yaakov Henkin, M.D., Danit R. Shahar, R.D., Ph.D., Shula Witkow, R.D., M.P.H., Ilana Greenberg, R.D., M.P.H., Rachel Golan, R.D., M.P.H., Drora Fraser, Ph.D., Arkady Bolotin, Ph.D., Hilel Vardi, M.Sc., Osnat Tangi-Rozental, B.A., Rachel Zuk-Ramot, R.N., et al., for the Dietary Intervention Randomized Controlled Trial (DIRECT) Group). Although the focus was on weight loss they looked at other lipids, etc. The participants were:
We conducted the trial between July 2005 and June 2007 in Dimona, Israel, in a workplace at a research center with an on-site medical clinic. Recruitment began in December 2004. The criteria for eligibility were an age of 40 to 65 years and a body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) of at least 27, or the presence of type 2 diabetes (according to the American Diabetes Association criteria) or coronary heart disease, regardless of age and BMI.
the mean age was 52 years and the mean BMI was 31. Most participants (86%) were men.
Patients were assigned one of three diets, Low-Carb, Mediterranean, and Low-Fat.
So, what happened to their weight?
The overall weight changes among the 322 participants at 24 months were −2.9±4.2 kg for the low-fat group, −4.4±6.0 kg for the Mediterranean-diet group, and −4.7±6.5 kg for the low-carbohydrate group.
Other measurements were
The waist circumference decreased by a mean of 2.8±4.3 cm in the low-fat group, 3.5±5.1 cm in the Mediterranean-diet group, and 3.8±5.2 cm in the low-carbohydrate group (P=0.33 for the comparison among groups).
Didn’t eating all that fat, meat and cheese cause them a cholesterol ratio problem? Not so much. Again LC came out on top since their HDL (good) number went up.
HDL cholesterol (Figure 3A) increased during the weight-loss and maintenance phases in all groups, with the greatest increase in the low-carbohydrate group (8.4 mg per deciliter [0.22 mmol per liter], P<0.01 for the interaction between diet group and time), as compared with the low-fat group (6.3 mg per deciliter [0.16 mmol per liter]).
Overall, the ratio of total cholesterol to HDL cholesterol (Figure 3D) decreased during both the weight-loss and the maintenance phases. The low-carbohydrate group had the greatest improvement, with a relative decrease of 20% (P=0.01 for the interaction between diet group and time), as compared with a decrease of 12% in the low-fat group.
The conclusions followed:
In this 2-year dietary-intervention study, we found that the Mediterranean and low-carbohydrate diets are effective alternatives to the low-fat diet for weight loss and appear to be just as safe as the low-fat diet. In addition to producing weight loss in this moderately obese group of participants, the low-carbohydrate and Mediterranean diets had some beneficial metabolic effects, a result suggesting that these dietary strategies might be considered in clinical practice and that diets might be individualized according to personal preferences and metabolic needs.
The similar caloric deficit achieved in all diet groups suggests that a low-carbohydrate, non–restricted-calorie diet may be optimal for those who will not follow a restricted-calorie dietary regimen. The increasing improvement in levels of some biomarkers over time up to the 24-month point, despite the achievement of maximum weight loss by 6 months, suggests that a diet with a healthful composition has benefits beyond weight reduction.
As a note:
Labeling the “low-carbohydrate” diet as such is questionable, since 40 to 42% of calories were from carbohydrates from month 6 to month 24, and data regarding ketosis support this view.
Here is another great study on the same subject (N Engl J Med 2003; 348:2074-2081. A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity. Frederick F. Samaha, M.D., Nayyar Iqbal, M.D., Prakash Seshadri, M.D., Kathryn L. Chicano, C.R.N.P., Denise A. Daily, R.D., Joyce McGrory, C.R.N.P., Terrence Williams, B.S., Monica Williams, B.S., Edward J. Gracely, Ph.D., and Linda Stern, M.D.).