Low-fat Diet May Not be Best Choice
July 30, 2008
Medical Research, Press Releases
NEW YORK, July 16, 2008 – A two-year study led by researchers from Ben-Gurion University of the Negev (BGU) reveals that low-carbohydrate and Mediterranean diets may be safer and more effective in achieving weight loss than the standard, medically prescribed low-fat diet, according to a new study published in the prestigious New England Journal of Medicine.
The study was conducted by BGU at the Nuclear Research Center in Dimona, Israel, in collaboration with Harvard University, The University of Leipzig, Germany and the University of Western Ontario, Canada.
In the two-year study, 322 moderately obese people were intensively monitored and were randomly assigned one of three diets: a low-fat, calorie-restricted diet; a Mediterranean calorie-restricted diet with the highest level of dietary fiber and monounsaturated/saturated fat; or a low-carbohydrate diet with the least amount of carbohydrates, highest fat, protein, and dietary cholesterol. The low-carb dieters had no caloric intake restrictions.
Although participants actually decreased their total daily calories consumed by a similar amount, net weight loss from the low-fat diet after one year was only 6.5 lbs. (2.9 kg) compared to 10 lbs. (4.4 kg) on the Mediterranean diet, and 10.3 lbs. (4.7 kg) on the low-carbohydrate diet.
“These weight reduction rates are comparable to results from physician-prescribed weight loss medications,” explains Dr. Iris Shai, the lead researcher.
The low-fat diet reduced the total cholesterol to HDL ratio by only 12 percent, while the low-carbohydrate diet improved the same ratio by 20 percent. Lipids improved the most in the low-carbohydrate, with a 20 percent increase in the HDL (“good”) cholesterol and, 14 percent decrease in triglycerides.
In all three diets, inflammatory and liver function biomarkers was equally improved. However, among diabetic participants, the standard low-fat diet actually increased the fasting glucose levels by 12mg/dL, while the Mediterranean diet induced a decrease in fasting glucose levels by 33mg/dL.
In addition to the findings, this two-year study is also important because of the relatively large number of participants coupled with a low drop-out rate – 95 percent were in the study after one year and 85 percent were still participating after the second.
Dr. Iris Shai is a researcher at the S. Daniel Abraham International Center for Health and Nutrition in the Department of Epidemiology at Ben-Gurion University of the Negev. She conceived the study with Dr. Stampfer, the senior author, while she was a Fulbright fellow at Harvard School of Public Health and Channing Laboratory in Boston, Massachusetts.
The trial conducted at the Nuclear Research Center in Israel involved unparalleled and significant cooperation between staff, participants and their spouses. The cafeterias in the workplace went through a “health revolution,” integrating the workplace cafeteria managers with clinical support and a nutritional advisor, in order to provide healthy food dishes that would fit each one of the dietary arms, as labeled with specific colors every day.
Along with careful workplace nutritional counseling, spouses of the trial participants were educated on how to keep the specific assigned diet strategy at home. The participants also completed electronic questionnaires, developed specifically for the study.
“The Nuclear Research Center Dimona highly values health promotion within the workplace,” said Dr. Dan Schwarzfuchs, director of the clinical department at the facility. “This is why it supported performance of such a nutritional study and enabled the outstanding adherence rate of the participants.”
“Clearly, there is not one diet that is ideal for everyone,” Shai states.
“We believe that this study will open clinical medicine to considering low-carb and Mediterranean diets as safe effective alternatives for patients, based on personal preference and the medical goals set for such intervention.
Furthermore, the improvement in levels of some biomarkers continued until the 24-month point, although maximum weight loss was achieved by 6 months. This suggests that healthy diet has beneficial effects beyond weight loss,” concludes Shai.
ABOUT AMERICANS FOR BEN-GURION UNIVERSITY
By supporting a world-class academic institution that not only nurtures the Negev, but also shares its expertise locally and globally, Americans for Ben-Gurion University engages a community of Americans who are committed to improving the world. David Ben-Gurion envisioned that Israel’s future would be forged in the Negev. The cutting-edge research carried out at Ben-Gurion University drives that vision by sustaining a desert Silicon Valley, with the “Stanford of the Negev” at its center. The Americans for Ben-Gurion University movement supports a 21st century unifying vision for Israel by rallying around BGU’s remarkable work and role as an apolitical beacon of light in the Negev desert.
About Ben-Gurion University of the Negev
Ben-Gurion University of the Negev embraces the endless potential we have as individuals and as a commonality to adapt and to thrive in changing environments. Inspired by our location in the desert, we aim to discover, to create, and to develop solutions to dynamic challenges, to pose questions that have yet to be asked, and to push beyond the boundaries of the commonly accepted and possible.
We are proud to be a central force for inclusion, diversity and innovation in Israel, and we strive to extend the Negev’s potential and our entrepreneurial spirit throughout the world. For example, the multi-disciplinary School for Sustainability and Climate Change at BGU leverages over 50 years of expertise on living and thriving in the desert into scalable solutions for people everywhere.
BGU at a glance:
20,000 students | 800 senior faculty | 3 campuses | 6 faculties: humanities & social sciences, health sciences, engineering sciences, natural sciences, business & management, and desert research.
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