How accurate are your exercise estimates? (Eric Thayer for The New York Times)

When people with weight problems talk about their exercise and eating habits, many doctors and nutritionists don’t believe them. That’s because studies show that overweight people commonly underestimate the amount of food they’re eating.

But exercise habits appear to be a different story. New research shows that people with weight problems are far more tuned into how much they exercise than they are often given credit for.

In a study presented at the Obesity Society’s annual meeting, researchers from Temple University’s Center for Obesity Research and Education in Philadelphia found that obese women were more accurate in reporting their activity levels than overweight or normal weight women. Read more…

Obesity is widely viewed as the nation’s biggest health problem. But research last week showing that one-third of obese people are “metabolically” healthy suggests that health can’t be judged by fat alone.

Indeed, there’s a growing body of evidence suggesting that many of our attitudes about health and weight are misguided. While excess weight clearly is a risk factor for poor health, it doesn’t appear to be the most important issue. About half of overweight people and one-third of obese people have normal “good” cholesterol, blood pressure and other cardiovascular risk factors. And several studies show physical activity is a far more important predictor of health than body size is.

“We know that obesity by itself is a major coronary risk factor,” said Dr. Kenneth Cooper, the fitness expert who launched the aerobics movement. “But you can’t just rely on weight. You’re better off being fat and fit than skinny and unfit.”

To read more about weight, fitness and health, read my full Well column here and then post your comments below.

In the future, everyone will be fat — or so warns a new study published online last month in the medical journal Obesity. About 66 percent of American adults are now overweight or obese, according to government estimates, and the report makes the dire prediction that, based on current trends, by 2048 the figure will reach 100 percent.

But that projection, which presumes a linear increase in the number of people who are overweight, is logically impossible, say several top statisticians. The reasons are outlined in one of my favorite columns, “The Numbers Guy,” written by the Wall Street Journal’s Carl Bialik.

“Employing that same logic, 13 out of every 10 adult Americans by then won’t have landlines,” Mr. Bialik wrote. “The phone forecast is impossible, of course, but it’s arguably no less solidly grounded than the obesity forecast.” Mr. Bialik also interviewed top statistician Donald Berry, chairman of the department of biostatistics at the University of Texas M.D. Anderson Cancer Center.

“Extrapolations are dangerous,” Dr. Berry explained. “Especially dangerous is to assume that trends are linear. Otherwise we’d conclude that Olympic swimmers will one day have negative times, there will be more Internet users than people, and more people on Earth than molecules in the universe.”

To read Mr. Bialik’s column, click here.

Good health comes in a variety of shapes and sizes. (Josh Haner/The New York Times)

Many overweight and obese people are metabolically healthy, while large numbers of slim people have health problems typically associated with obesity, a new study shows.

The findings, based on national health data collected from 5,440 adults, shows that weight often is not a reliable barometer for health. In addition to looking at height and weight, the study, published this week in The Archives of Internal Medicine, tracked blood pressure, “good” cholesterol, triglycerides, blood sugar and an inflammatory marker called c-reactive protein, all of which are viewed as indicators of cardiovascular health.

Overall, thin people were still metabolically healthier than people who were overweight or obese. But being a normal weight was not a reliable indicator of health. In the study, about 24 percent of thin adults, or about 16 million people, posted unhealthy levels for at least two of the risk factors.

By comparison, among the overweight, Read more…

Few topics generate more heated discussion than diet and weight loss, and for the past week, readers have posted hundreds of comments reacting to the latest diet research.

The latest study, published in The New England Journal of Medicine, compared three diets. Some participants cut fat, others counted carbohydrates in a version of the Atkins diet, while others adopted Mediterranean-style eating habits. Some people declared the research a vindication for Atkins, others criticized my view of the study as more evidence that diets don’t really work.

For some needed perspective, I turned to Gina Kolata, a New York Times reporter and author of the wonderful book, “Rethinking Thin: The New Science of Weight Loss — and the Myths and Realities of Dieting.” Not only is Gina well versed in the science of weight loss, but she has an unusually compassionate take on the efforts of the dieters in this recent study and all people who struggle with their weight. Read more…

High-fructose corn syrup is a sweetener used in many processed foods ranging from sodas to baked goods. While the ingredient is cheaper and sweeter than regular sugar, new research suggests that it can also make you fatter.

In a small study, Texas researchers showed that the body converts fructose to body fat with “surprising speed,” said Elizabeth Parks, associate professor of clinical nutrition at the University of Texas Southwestern Medical Center in Dallas, in a press release. The study, which appears in The Journal of Nutrition, shows how glucose and fructose, which are forms of sugar, are metabolized differently. Read more…

Overweight people already know they are overweight. So should doctors keep nagging them to lose pounds?

No surprises here. (PictureNet/Corbis)

That’s the issue tackled recently by one of my favorite medical blogs, called “Musings of a Distractible Mind.” The author, who goes by “Dr. Rob,” is Dr. Robert Lamberts, an Augusta, Ga., physician who is board certified in internal medicine and pediatrics. On his blog, Dr. Rob muses about a variety of topics like llamas, twinkies and favorite patients. But I was particularly moved by a recent post, which was written after Dr. Rob’s encounter with an overweight patient who was clearly accustomed to being lectured about obesity. As Dr. Rob was about to discuss whether the man needed surgery for sciatica and back pain, the patient interrupted him, hanging his head in shame and blaming his weight for the problem. Read more…

Young, fit and feeling fat? (Janet Hostetter for The New York Times)

At a time when much of the Western world is focusing on obesity problems, even teens who are at a healthy weight may develop a distorted body image.

That’s what German researchers found after surveying nearly 7,000 11- to 17-year-olds, asking them to describe their bodies. Options included far too thin, a bit too thin, just the right weight, a bit too fat and far too fat.

About 75 percent of the kids fell into the normal-weight category. However, half the normal-weight girls and a quarter of the normal-weight boys still described themselves as being too fat.

When those teens were given quality-of-life and self-esteem tests, normal-weight children who believed they were fat scored as poorly as children who really were obese. And normal-weight children who felt fat actually scored worse on family relationship questions than obese children. The findings were published in the current issue of Deutsches Ärzteblatt International, a German medical journal.

Although the data come from Germany, studies in the United States also suggest body image concerns are prevalent among American teens and adolescents. A 1999 study from the American Dietetic Association found that 55 percent of 7- to 12-year-old girls said they wanted to be thinner.

The data suggest that efforts to address unhealthy weight gain and obesity among young people have the the potential for “collateral” damage in normal-weight kids, who may develop self-esteem problems. An accompanying editorial noted that adolescents are exposed to considerable social pressure to be thin.

Your waistline may be the best barometer of your health. (Susan Farley for The New York Times)

Imagine if your employer started measuring your waist as a measure of your health.

That’s what’s happening in Japan. As my colleague Norimitsu Onishi explains in today’s Times, a Japanese law that came into effect two months ago requires companies and local governments to measure the waistlines of Japanese adults. The government limits are 33.5 inches for men and 35.4 inches for women. Those who exceed the standard and also have another weight-related health concern are given “dieting guidance” to drop weight. (To read the full story, click here.)

While the Japanese plan seems onerous, it’s not without scientific basis. Studies clearly show a person’s health risks increase as waist size grows. Read more…

A 5-year-old leaving an exercise program for overweight children. A new study suggests that the epidemic of childhood obesity finally may be leveling off. (Matt Slocum/Associated Press)

The above photo appeared with a recent post I wrote about childhood obesity. Readers were critical of me not only for showing the picture, but for my later comment that I found the picture to be “sad.” I see a child who likely is teased by peers and is at risk for a lifetime of health problems. But readers disagreed.

“It’s also very unfortunate, TPP, that you felt the need to say a photo of a little girl having her hands held lovingly by two adults is ’sad,’” wrote reader Cathy W. “Yes, her weight is unfortunate and unhealthy, but you don’t know anything else about this little girl, so please refrain from judgments. I know it’s shocking to believe, but an overweight child can still be happy and loved!”

“I was an overweight child 40 years ago,” wrote reader Janet V. “But I was never sad, so I really am offended by your characterization of the child’s picture as such.”

I asked Dr. David Ludwig, director of the childhood obesity program at Children’s Hospital Boston, to talk about overweight kids and the controversial picture. To hear our conversation, click the link below. To read the original post and comments, click here.

Listen to the Podcast (mp3)

A new study suggests that the epidemic of childhood obesity finally may be leveling off. (Matt Slocum/Associated Press)

A glimmer of hope has emerged in the battle against childhood obesity. As I wrote about in today’s Times, the Centers for Disease Control and Prevention is reporting that childhood obesity rates appear to have hit a plateau.

Nobody is celebrating just yet. Now health officials and families need to focus on helping the one out of three children in the United States who are already overweight or obese. Fortunately, the problem is potentially easier to battle in children than adults.

“Childhood is the ideal time to address this problem for a lot of reasons,” said Dr. David Ludwig, director of the child obesity program at Children’s Hospital in Boston. “The lifestyle habits that cause the problem haven’t been entrenched as long with children as they have with adults. And all but the most heavy children can basically outgrow their problem by holding their weight constant as their height increases or at least slow their rate of weight gain.”

Because kids are constantly growing, it can be tough to figure out how much your child should be eating. They key is to provide a ready supply of healthful foods and limit so-called “energy dense” foods — things like fried chicken nuggets or pastries that pack a lot of calories in each bite.

A number of Web-based tools can also help. The Children’s Nutrition Research Center at the Baylor College of Medicine provides an energy calculator that can help you determine how many calories your child should be eating each day. To use the calculator, click here.

To find out whether your child is at a healthy weight or at risk of being overweight, you should use a childhood body mass index calculator. The C.D.C. provides one here. And click here to learn more from the C.D.C. about using B.M.I. calculations in childhood health.

Women’s weight discrimination. (Jodi Hilton/The New York Times)

It only takes a modest weight gain for a woman to experience weight discrimination, but men can gain far more weight before experiencing similar bias, a new study shows.

The notion that society is less tolerant of weight gain in women than men is just one of the findings suggested by a new report from the Rudd Center for Food Policy & Obesity at Yale University, published this month in the International Journal of Obesity. Read more…

Dieters are more likely to lose weight and keep it off if they have contact with a weight-loss counselor, a new study shows.

The report, led by researchers at Duke University Medical Center and published today in The Journal of the American Medical Association, shows just how difficult it is for dieters to maintain their weight loss. The study began with 1,685 overweight or obese adults who weighed on average 213 pounds. The group was successful at losing weight, with an average weight loss after six months of 18.7 pounds.

About 1,000 people who lost 9 pounds or more took part in the second phase of the study. Some used an Internet-based weight counseling tool, while others had regular personal contact with a weight-loss counselor. A third group received basic instruction on maintaining weight loss, and those dieters attempted to keep the weight off on their own.

Monthly personal contact meant the participants had telephone contact with a counselor for 5 to 15 minutes each month, except for every fourth month, when they had a 45- to 60-minute individual face-to-face session. The Web-based program gave participants unlimited access to a Web site designed to support weight loss maintenance, with interactive features allowing participants to set personal goals and action plans for the next week and to graph personal data over time.

More than two years later, most everyone had gained back some of their weight. The people who tried to maintain their weight on their own fared the worst, gaining back an average of 12.1 pounds. People who used the Web-based tool gained back 11.5 pounds. However, those people who took part in the personal contact group gained back the least — regaining 8.8 pounds.

Although personal contact only resulted in a 3.3 pound additional benefit, the study authors noted that even small losses can improve health. Every kilogram (2.2 pounds) of weight loss is associated with an average decrease in systolic blood pressure of 1.0 to 2.4 mm Hg and a 16 percent reduction in diabetes risk, the authors said. At the end of the study, more than 45 percent of those who had received counseling were still maintaining at least 9 pounds of weight loss, an amount with clear clinical benefits, they noted.

Among teen girls, notions of popularity may influence weight gain. (Nicole Bengiveno for The New York Times)

Girls who think they aren’t popular are at higher risk for weight gain, according to a new study.

It’s long been known that being overweight can lead to social exclusion for teens, but in a study published this week in the Archives of Pediatrics & Adolescent Medicine, researchers at Harvard University took on a slightly different question: whether a student’s perceptions of her social status played a role in her weight.

To find out, the researchers recorded the body mass index of nearly 4,500 girls ages 12 to 18. The teens were also asked to rank themselves from one to 10 in the social hierarchy at their school, based on the following question:

At the top of the ladder are the people in your school with the most respect and the highest standing. At the bottom are people who no one respects and no one wants to hang around with. Where would you place yourself on the ladder?

Two years later, the researchers found, all of the girls had gained weight — no surprise, since they were all growing. But teens who had rated themselves at four or lower had gained more. Read more…