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The Honolulu Advertiser
Posted on: Thursday, July 6, 2006

Forget fad diets for long-term weight loss

By Amy Tousman

A study comparing four fad diets found that weight loss among participants was similar between all diet plans, although dropout rates were high on all plans.

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Q. Will I lose more weight on a low-carbohydrate diet or a low-fat diet?

A. In the short run, you can lose weight on many types of diets. The more important question to ask is which plan keeps the weight off permanently. Since many fad diets come and go, it is important to study several approaches.

Last January, the Journal of the American Medical Association published a study comparing four popular diets. Outcome measures included effectiveness of the diets for weight loss and cardiac risk factor reduction over a one-year period.

The study looked at 160 overweight or obese adults known to have high blood pressure, abnormal cholesterol levels or elevated blood sugar levels. They were randomly assigned to one of four diets:

  • Atkins (low carbohydrate): 20 grams daily carbohydrate initially, gradually increasing to 50 daily carbohydrate grams.

  • Zone (moderate carbohydrate): 40 percent carbohydrate, 30 percent fat, 30 percent protein at all meals.

  • Weight Watchers: restriction of portion sizes and calories to 1,200 to 1,600 calories daily.

  • Ornish (very low fat): 10 percent fat, vegetarian diet.

    Dietary advice was given for the first two months. After this time, participants chose their own level of adherence to the recommended diet.

    Dropout rates were high on all plans. Only 53 percent of those on the Atkins plan and 50 percent of those on the Ornish plan completed the study. Completion rates were somewhat better for Zone and Weight Watchers with 65 percent staying on each of those plans. The higher dropout rates for Atkins and Ornish groups suggest many individuals found these diets to be too extreme.

    For those who completed the study, weight loss also was similar between all diet plans. After one year, average weight loss for those on Atkins was 5 pounds, while the average for each of the other plans was 7 pounds. In each diet group, approximately 25 percent of the initial participants kept off more than 5 percent of their initial body weight after one year.

    None of the diets reduced blood pressure or blood sugar significantly; however the ratio between bad and good cholesterol improved on all four plans.

    This study demonstrates that different approaches work for different people. It is important to choose an eating plan that you can stick with over the long haul. Sometimes making a few small changes works best. Forget the latest diet fad and make changes you can live with permanently.

    Amy Tousman is a registered dietitian with the Health Education Center of Straub Clinic and Hospital. Hawai'i experts in traditional medicine, naturopathic medicine and diet take turns writing the Prescriptions column. Send your questions to: Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; fax 535-8170; e-mail islandlife@honoluluadvertiser.com. This column is not intended to provide medical advice.