Archive for Wednesday, June 6, 2007

Studies dish the skinny on diets

June 6, 2007


Americans don't give up easily. Those hoping to lose weight have put a whole new crop of diet books on the best-seller list. The science-laden "You on a Diet," the wine lover's "Sonoma Diet," the manly "Abs Diet," and the kinder, gentler Oprah Winfrey-endorsed "Best Life Diet" are just some of the recent diets.

Consumer Reports recently rated those four as well as other popular diet books and plans, based on nutritional analysis from the U.S. Dietary Guidelines for Americans and the critiques of a panel of diet experts. None of the seven books has been put to the acid test of a large clinical trial.

Backed by research, nutritionists have come to a rough agreement on what a truly healthful diet looks like: Eat plenty of fruits and vegetables, and some lean meat and fish, healthy fats and whole grains. And minimize refined grains, potatoes, full-fat dairy products and added sweeteners - especially in the form of soft drinks. Studies of large populations the world over have shown that this diet reduces the risk of heart disease, diabetes and certain cancers.

Diet books: lean evidence

With some minor variations, all the diet plans CR evaluated recommended some version of this eating plan.

CR's top-rated plan was "The Best Life Diet" by Bob Greene (Simon & Schuster, $26). The diet's first phase involves exercise and a recommended eating schedule. Calorie reduction starts in phase two. Reviewers liked the personalized advice and section on exercise, but cautioned that dieters might be discouraged when they don't lose weight in phase one.

Other very good books included "Eat, Drink, & Weigh Less," by Mollie Katzen and Walter Willett, M.D. (Hyperion, $14.95), "You On A Diet," by Mehmet C. Oz, M.D., and Michael F. Roizen, M.D. (Simon & Schuster, $25), and "The Abs Diet," by David Zinczenko with Ted Spiker (Rodale, $15.95). Reviewers liked the scientific accuracy in "Eat, Drink, & Weigh Less," but thought the book's 1,910-calories-a-day sample diet was excessive. "You On A Diet" advocates a two-week "rebooting program" that bans sugar, saturated fat and refined flour. Some reviewers were skeptical that habits can change for good in just 14 days. And while "The Abs Diet" promises "a six-pack in six weeks" by eating six power-packed meals a day, reviewers were dubious and disliked the diet's emphasis on whey supplements.

Reviewers gave lower marks to "UltraMetabolism," by Mark Hyman, M.D. (Scribner, $25). The author's theory that people get fat because their systems become toxic, inflamed, stressed and imbalanced goes beyond scientific evidence, experts said, and the diet was overly restrictive and complicated.

Diet plans: tested efficacy

There's plenty of scientific evidence, meanwhile, to back up the efficacy of "The Volumetrics Eating Plan" (Harper, $15.95) by Barbara Rolls, a professor in the department of nutritional sciences at Pennsylvania State University. Recent clinical trials show that Volumetrics produced the best overall weight loss of the eight diet plans that CR evaluated. The diet aims to maximize the amount of food available per calorie, mainly by using reduced-fat products, liberal addition of vegetables and low-fat cooking techniques. Other plans that rated high in CR's diet plan ratings were the venerable Weight Watchers program (it uses weekly meetings and weigh-ins for motivation and behavioral support), Jenny Craig (which features individual counseling and meal plans) and Slim-Fast (widely available in drug stores and supermarkets).

Lowest-scoring of the eight plans was the once-skyrocketing Atkins Diet. There's growing evidence that dieters aren't as hungry on Atkins as on some other plans.

But many find this granddaddy of low-carb diets too restrictive, so long-term adherence is below average and long-term weight loss is average. And the diet's nutritional profile is far outside dietary guidelines.

Visit the Consumer Reports Web site at


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