New diet winners We rate the diet books and plans. Plus: 8 strategies that work
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 titles.
We have rated those four and other popular diet books, based on our nutritional analysis and the critiques of a panel of diet experts. None of these books has yet been put to the acid test of a large clinical trial. Our analysis found that most provided good nutrition advice, but the panel perceived real differences in their quality of information. Some of the experts, for instance, thought that some nutritional theories in “UltraMetabolism” didn’t have solid science behind them.
We also have some new winners among diet plans that have been studied in clinical trials, reflecting data published since our 2005 diet Ratings. Our top-rated diet is “The Volumetrics Eating Plan” by Barbara Rolls, Ph.D., a professor in the department of nutritional sciences at The Pennsylvania State University.
Weight Watchers came in second, with Jenny Craig a very close third (see Diet plans, which is available to ConsumerReports.org subscribers).
We’ll also brief you on the real progress that scientists have made in identifying eating patterns and behavioral tricks that help at least some dieters cut calories without feeling too deprived. Most of those strategies appear in the diet books we evaluated. Whether those insights will translate into a widespread improvement in weight-loss success remains to be seen. But if you’re looking to shed pounds, there’s some solid science on which to base your choice of a diet plan or book, or create a do-it-yourself approach.
The basic formula for losing weight has not changed: Consume fewer calories than you burn--about 500 fewer every day, to lose about a pound a week. Not an easy task, however, or why would legions of people try, fail, and fail again in their weight-loss efforts?
But it’s not impossible. The Consumer Reports National Research Center’s survey of CR subscribers, published in June 2002, found that 25 percent of respondents who had ever tried to lose weight did shed at least 10 percent of their starting weight and kept it off for a year or more.
Successful dieters are finally getting a little attention from scientists, who are examining what those people do to control their weight. This is a welcome change from the many decades of weight-loss research that consisted of scientists coming up with low-calorie, low-fat diets and proving that they would work if people followed them strictly. That was the rub, of course. Most people could not follow them strictly for very long. Pioneering researchers are now seeking practical ways to help dieters feel full without consuming too many calories.
These efforts have begun to produce practical, evidence-based tips for do-it-yourself dieters who are attempting to lose weight on their own, without the help of any formal program or counseling. None of these will work for everyone, but you should be able to find some that will work for you.
While dieters might prefer to save calories by skipping breakfast, eating a substantial morning meal is recommended by every diet book we analyzed. Seventy-eight percent of the successful losers at the National Weight Control Registry say they eat breakfast, typically some cereal and fruit. The Registry, which enrolls people who can document that they have lost more than 30 pounds and kept it off for at least a year, has more than 5,000 members.
Many diet experts have backed away from avoiding fats, though this traditional approach is still used by very low-fat plans such as Dean Ornish’s “Eat More, Weigh Less” and the diet endorsed by the Pritikin Longevity Center. Some research shows that a very low-fat diet can slow the progression of heart disease and breast and prostate cancer. But the dropout rate from that type of diet is high.
Scientists now distinguish good fats from bad, based on copious evidence about their effect on blood cholesterol. Most of the popular diet books we analyzed warn against eating “bad” fat, including trans fats created when vegetable oil is hydrogenated, and the saturated fats from meat and dairy sources. Good fats include olive and other monounsaturated oils, nuts, avocados, and omega-3 oils from seafood and plant sources.
But good or bad, all fats have big calorie counts. They contain 9 calories per gram, compared with 4 per gram for carbohydrates and protein. The diet menu in “Eat, Drink, and Weigh Less” recommends liberally consuming healthy fats. But when we analyzed the meal plan, it totaled 1,910 calories per day, about 40 percent of them from fat, which would make weight loss unlikely for many people.
Backed by a growing body of research, nutritionists have come to a rough consensus 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.
With minor variations, all the diet books we evaluated recommended some version of this eating plan--and their uniformly high ratings for nutrition reflect that. But they didn’t seem “willing to emphasize calories, or tell people to ‘eat less,’” said Rena Wing, Ph.D., a professor in the department of psychiatry and human behavior at Brown University’s medical school and a founder of the National Weight Control Registry.
The bottom line is that no matter how “healthy” your diet is, you still have to restrict quantities to lose weight. “The Best Life Diet,” which got top marks from our reviewers, provides detailed instructions on proper serving sizes for many different types of foods.
To control weight from exercise alone requires a devotion that few nonathletes can summon: 60 to 90 minutes a day of moderate to vigorous exercise. But increasing the time you spend out of your chair--in formal exercise and activities such as housework and yard work--helps you burn at least some calories. And an active lifestyle will help you maintain your weight loss. National Weight Control Registry participants report doing about an hour a day of moderate-intensity exercise, like brisk walking. Of the books we evaluated, “You on a Diet,” “The Best Life Diet,” and “The Abs Diet” got high marks for their clear and detailed sections on exercise.
Virtually all diets restrict or eliminate “bad” highly refined carbs such as white bread, cookies, chips, and soft drinks. But a wholesale cutback on grains, fruits, and the sweeter vegetables, such as beets and carrots, was first popularized by the Atkins diet. Recent research has found that for up to a year, some people can indeed safely lose weight on Atkins. In the most recent study, published in the March 7, 2007, Journal of the American Medical Association, 311 overweight women were randomly assigned to one of four diets: Atkins, Zone, Ornish, and a control group on a traditional low-fat menu plus various behavioral strategies. On some measures, Atkins dieters came out ahead. “They had better triglyceride lowering than Zone dieters, better HDL raising than Ornish, and better blood-pressure lowering than all three,” said Christopher Gardner, Ph.D., assistant professor of medicine at Stanford University, director of the study. But while Atkins dieters lost modestly more weight than Zone dieters, at 12 months their weight loss was similar to those on the Ornish or control diet.
Very low-carb diets are not for everyone. As Gardner points out, at least some participants lost 30 pounds and kept it off for a year on all the diets in the study. Successful losers in the National Weight Control Registry overwhelmingly report that they consume plenty of carbs while restricting fat and portions.
One way to spare calories and still eat a satisfying amount of food is to focus your diet on foods that have fewer calories per bite, or low “energy density.”
Starting your meals with a low-calorie soup or salad and eating main dishes that are full of vegetables and fruits are the main tactics of the low-density diet.
Using government food consumption surveys, researcher Barbara Rolls has shown that people who eat a low-energy-density diet consume hundreds fewer calories per day than those with a high-density diet, yet eat a greater amount of food. And in research on volunteers in her Penn State lab, Rolls has found that consuming a low-density diet helps people lose weight and keeps them thinner. “Volumetrics,” based on this research, has now been studied in clinical trials and finished at the top of our diet Ratings.
Whether they say so explicitly or not, many of the other diets and books we evaluated recommend strategies to reduce the energy density of food. People on the Weight Watchers point system, for instance, soon learn that if they spend too many of their daily point allotment on calorie-dense foods, they’ll go to bed hungry. “The Sonoma Diet” sternly limits dieters to no more than 3 teaspoons of olive or canola oil per day but permits unlimited quantities of low-calorie-density vegetables such as broccoli, spinach, and tomatoes. The Ornish diet, which bans fats almost completely, had the lowest energy density of any that we studied.
Many of the books we reviewed discourage the practice of daily, or even weekly, weigh-ins, at least in the initial stages of a weight-loss diet. But 75 percent of National Weight Control Registry members weigh themselves at least weekly. “They remain vigilant about their weight loss,” Wing said. “It seems likely that if they gain a pound or two, they take steps to lose it before it can accumulate.”
Though many books promise readers they’ll be eating a huge variety of foods, in practice they limit variety of high-calorie foods. “The South Beach Diet,” “The Sonoma Diet,” and “UltraMetabolism” were especially restrictive in their severe initial phases.
Since variety stimulates the appetite, the more monotonous your diet, the less you’ll eat. So steer clear of buffet tables, which can be the dieter’s worst enemy.
Consumer Reports has no relationship with any sponsor or advertiser of CTV.
Copyright © 2004-2008 Consumers Union of U.S., Inc.