The low-carb diet is 'out' and portions are getting bigger. Can the obesity epidemic be fixed?
By Jeanie Lerche Davis
WebMD Weight Loss Clinic - Feature
Reviewed By Michael Smith, MD
Open wide, America, for the Monster Burger. It's a near-mountain of beef, bacon, and cheese -- fully loaded with 1,420-calories and 107 grams fat. In our diet-dizzy, low-carb world, it's almost comic relief. But nutritionists are not amused.
Putting this megaburger on the fast-food market "is social irresponsibility," says Kathleen Zelman, MPH, RD, director of nutrition for the WebMD Weight Loss Clinic. "Unless you're feeding your entire family that one burger, it's utter insanity."
This year, America turned a corner. Low carb and low fat became the dieter's Holy Grail.
Many fast-food outlets halted supersizing. Many began offering salads and fresh fruit. Kids' menus were retooled. Low-carb grilled chicken, carrots, celery, steamed broccoli, and applesauce are showing up on kids' menus -- not just the typical burgers, fried chicken fingers, and french fries.
Low-carb milk, pasta, and baked goodies popped up in grocery stores. Many products, however, had the same number of calories as the original versions. Plus, they were pricey.
Published reports now show:
- This fall, fewer people were following low-carb diets. In December 2003, nearly 12% were following either the Atkins or South Beach diet, compared with 8% by Oct. 2004.
- Low-carb products are gathering dust. Total low-carb sales made double- and triple-digit gains in the first half of 2004. But for the 13-week period ending Sept. 25, total low-carb product sales grew just 6%.
The low-carb craze, many say, is fading fast.
Lessons Learned From Low-Carb Craze
"The best thing about 'low-carb consciousness' is that people have learned about smart carbs," Zelman tells WebMD. "There's very little nutritional value in simple low-carb items like sodas, white breads, and pastas. In a healthy diet, those are the extras, not the essentials -- fruits and vegetables, which are loaded with vitamins, minerals, antioxidants, and disease-prevention substances.
"You can lose weight any number of ways -- taking drugs or [by trying] any bizarre fad diet," she says. "But true weight loss is about making behavior changes that caused you to gain weight in the first place. It's about sustainability. You can't stay with the Atkins, low-carb lifestyle forever."
Skimping on food just isn't the answer, research is showing. A moderate-fat diet -- plus getting an hour of exercise daily -- that's what works best. In fact, the amount of carbs doesn't even matter, according to a 10-year study involving 2,700 members of the National Weight Control Registry.
The registry includes only people who have shed 30 pounds or more and kept it off. This year, the USDA used this database to develop the 2005 food pyramid guide.
"No body of evidence is more compelling than those in the National Weight Control Registry," Zelman tells WebMD. "It shows the magic bullet that's working for people who have lost weight and kept it off."
Exercise is that magic bullet, says registry director James O. Hill, PhD, director of the Center for Human Nutrition at the University of Colorado Health Science Center at Denver.
In his study, Hill analyzed eating patterns and lifestyle habits for registry members in 1995 and in 2003. He found striking differences:
- In 1995, those joining the registry had a calorie intake of roughly 1,400 per day; 24% calories from fat, and 56% from carbs.
- In 2003, calorie intake was the same, 1,400 -- but 30% fat and 49% carb calories, a significant shift. However, only a small percentage of these kept the weight off, he adds.
What works for successful, long-term weight loss? Based on data in Hill's registry, this pattern emerges:
- Moderate-fat diet. That means 25% of daily calories from fat. "It's low, but it's not Dean Ornish low. You can do that in real life," says Hill.
- Lots of carbs. Carbs fill in the bulk of remaining calories, then protein. The number of carb calories isn't really important if you eat a moderate-fat diet -- and if you exercise, he adds.
- 60 minutes of exercise daily. Set up a "core" 30-minute activity, such as a noontime walk. Another 30 minutes gets worked in during the day.
With the low-carb South Beach and Atkins diets, physical activity doesn't get mentioned, Hill notes. "But without exercise, it's harder to keep weight off."
Also, people have trouble sticking with a too-restrictive low-carb/low-fat diet, he tells WebMD. "These fad diets? people who are regimented can do them for a long time. But most people get back to real life after awhile."
This year's diet research backs up Hill's finding:
Thumbs Up: Thin People Worldwide Eat 'Good' Carbs
A four-continent study showed the same pattern: The thinnest people in the world eat the most carbs. This comes from a survey of 4,000 men and women living in the U.S., U.K., Japan, and China.
"Without exception, a high-complex-carbohydrate, high-vegetable-protein diet is associated with low body mass," reports researcher Linda Van Horn, PhD, of Northwestern University in Evanston, Ill. She presented her findings at the 44th American Heart Association Annual Conference on Cardiovascular Disease Epidemiology and Prevention this year.
This high-carb diet is full of high-fiber vegetables, fruits, beans, and whole grains -- not french fries, not white rice, and certainly not doughnuts. Also, those who exercised more tended to be lighter -- even though they ate more calories, Van Horn reports. High-protein diets were associated with higher body weight, she says.
Thumbs Up: Low Fat for Slow Weight Loss
This year, two studies pitted a low-carb diet against a low-fat diet. The upshot: Low-carb is good for a quick, six-month weight-loss program. But over one year's time, both diet groups lost similar amounts of weight -- 11 to 19 pounds on the low-carb diet and 7 to 19 pounds on the low-fat diet.
One big difference: The low-fat group simply lost weight more slowly, reports study researcher Frederick F. Samaha, MD, with the Philadelphia Veterans Affairs Medical Center. Both groups of dieters had difficulty, however, sticking with their diets.
Thumbs Up: Choose Carbs, Fats Wisely
This year, many of us also learned -- the hard way -- that many low-carb diets don't have staying power. Therefore, it's difficult sticking with them long term, reports Arne Astrup, MD, PhD, head of the Institute of Human Nutrition at the Centre for Advanced Food Research of the Royal Veterinary and Agricultural University in Copenhagen, Denmark.
Astrup reviewed the scientific literature on low-carb diets like Atkins. For up to one year, a low-carb diet is more effective for weight loss than a low-fat diet. However, after one year, low-carb dieters begin regaining weight, he notes. Also, there were side effects: headache, muscle weakness, cramps, and diarrhea.
Thumbs Down: High-Fat Diet Never Good
When is a high-fat diet ever a good thing? Never, nutritionists say. There's big evidence that, when cutting carbs, beefing up fat just won't work. A poll involving 1,200 Minnesota residents found that, from 1999 to 2000, people's diets got better in terms of eating fewer high-fat foods and in daily cholesterol intake. But in 2001 and 2002, those diets got worse and worse.
The culprit? Likely it was the low-carb, high-fat diets that became increasingly popular during those years, says Mayo Clinic researcher Randal J. Thomas, MD. Any plan that increases the amount of saturated fat in your diet is "a problem," he writes. Saturated fat, which comes mostly from animal products, has been strongly linked to heart disease as well as weight gain.
But cut back too much on carbs, and your body -- including your brain -- "is probably suffering from the lack of glucose to burn, and that is disturbing the normal function of tissues," says Astrup.
"Everyone's writing the death certificate on low-carb," Hill tells WebMD. "People who have tried it say they just got tired of if. Eating a 25%-fat diet is something you can do in real life. But you also need one hour of exercise a day. That's the reality, if you want big weight loss. It's the price you pay for obesity. One hour a day keeps off 70 pounds a year."
SOURCES: Kathleen Zelman MPH, RD, director, nutrition, WebMD Weight Loss Clinic. James O. Hill, PhD, director, Center for Human Nutrition at the University of Colorado Health Science Center at Denver. North American Association for the Study of Obesity Annual Scientific Meeting, Las Vegas, Nov. 14-18, 2004. USA Today, Dec. 15, 2004. The New York Times, Dec. 5, 2004. WebMD Medical News: "Low-Carb Diets Work, but Safety Still an Issue." WebMD Medical News: "More Carbs, More Exercise = More Weight Loss." "Low-Carb Diet War: High-Protein vs. High-Fat." Low-Carb, Low-Fat Diets Get Similar Results."
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