The study, published last week as a peer-reviewed letter in the prestigious New England Journal of Medicine, updates the landmark diet study carried out on 322 moderately obese personnel in the workplace over a period of two years, and followed up four years after the end of the intervention. The original study was called DIRECT, for Dietary Intervention Randomized Controlled Trial.
Dr. Dan Schwarzfuchs of the Dimona center, where employees were put on diets and the results observed, said: “Our follow- up subsequent data shows lasting, positive effects of Mediterranean and low-carbohydrate diets six years later.”
BGU researchers Dr. Iris Shai and Rachel Golan added: “Data from trials comparing the effectiveness of weight-loss diets are frequently limited to the intervention period. The results after four years suggests that the lipid profile (lower cholesterol, triglycerides and arteriosclerosis) improved over the long term, regardless of partial regain.”
The Mediterranean diet of low meat intake and high consumption of vegetables, fruits, whole grains, pulses and olive oil, as well as the low-carb diet, had a beneficial effect even though the participants regained some weight. But people on a low-fat diet did not have the same consistent and beneficial results.
Four years after the trial was concluded, participants had regained an average of almost 2.7 kg. Since the beginning of the trial, participants who followed the Mediterranean diet lost an average of 3.1 kg., while those on the low-carb diet lost 1.7 kg. Thus the Mediterranean diet was significantly more effective.
After four years post-intervention, more than two-thirds (67 percent) of the DIRECT participants had continued with their original assigned diet, 11% switched to another diet and 22% were not dieting at all.
The researchers also found that after six years, the highdensity lipoprotein (HDL or “good cholesterol”)/low-density lipoprotein (LDL or “bad cholesterol”) ratio remained significantly lower only in the low-carbohydrate diet. Triglyceride (another potential harmful blood fat) levels remained significantly lower in the Mediterranean and low-carbohydrate diets.
The researchers are now performing a new long-term dietary intervention trial that targets weight-loss mechanisms relating to other different dietary strategies, including novel techniques.
