Study: Weight-loss surgery cuts cancer risk in women

Weight-loss surgery can sometimes reverse type 2 diabetes and ease other obesity-related conditions. Now, new research suggests that obese women who undergo bariatric surgery experience a 42 percent drop in their cancer risk.

Exactly why this occurs and whether it's also true for obese men is not yet clear. Obesity is a known risk factor for colon, breast, endometrial, kidney and esophageal cancers. However, the researchers found that the surgery-related weight loss and drop in caloric intake did not seem to be solely responsible for the decline in the women's cancer risk, according to the report in the July issue of Lancet Oncology.

"Evidently, one or several risk factors for cancer are favorably influenced by bariatric surgery in women," said lead study author Dr. Lars Sjöström, a professor of medicine at Sahlgrenska University Hospital, in Gothenburg, Sweden.

In the study, researchers followed two groups for an average of 10.9 years -- 2,010 men and women who had weight-loss surgery and 2,037 obese people who did not undergo surgery. Those who had the surgery lost roughly 44 pounds, compared to just 3 pounds in those who did not. During the 10-year period, 117 people who had surgery developed cancer, as did 169 of their counterparts who tried to lose weight nonsurgically. Health.com: 20 little ways to drop pounds and keep them off

There were 79 cancers diagnosed in women who had surgery, compared with 130 cancers in the other women; a wide variety of cancer types were lower in women who had bariatric surgery. Still, the researchers did not find a statistical link specifically between weight loss or caloric intake after surgery and the reduction in cancer risk. They also found no cancer risk reduction for men who had surgery.

However, there were more women than men in the study. A larger study might detect an effect in men, too, the researchers note. Still, this is not the first study to suggest that weight-loss surgery does not reduce cancer risk in men, and it's possible that hormonal differences between the sexes may play a role.

For example, higher levels of the female sex hormone estrogen can stimulate the growth of breast and endometrial cancers, and fat cells are known to produce estrogen.

"Women are more sensitive to estrogen, so you might expect to see a major difference in estrogen-related cancers after surgical weight loss," said Dr. Neil Hutcher, the director of bariatric surgery at St. Mary's Bon Secours Hospital, in Richmond, Virginia.

It's also possible that obesity-related cancers that are more common in men -- such as colon, rectal, and kidney cancers -- may simply take longer to manifest than weight-related cancers in women, according to an editorial by Dr. Andrew G. Renehan of the University of Manchester, in the United Kingdom. Therefore, a longer study may show an advantage for men.

"I think the message here is that obesity increases the risk of cancer, [so] more aggressive screening for those cancers in obese people is indicated, especially breast, uterine, and colon cancers," said Dr. Gregg H. Jossart, of Laparoscopic Associates of San Francisco, who was not involved in the study. "Finally, sustained weight loss through obesity surgery probably does decrease the risk of death from colon cancer-- men are most at risk for this-- but the study population is simply not large enough to determine this." Health.com: Easy weight-loss recipes

The weight-loss surgery techniques used in the study may also partly explain the findings. The majority of participants had vertical banded gastroplasty (commonly known as stomach stapling), in which the upper stomach is stapled to create a smaller pouch; some had adjustable gastric banding, in which a silicone band is placed around the top of the upper part of the stomach to restrict food intake. Health.com: Raising the salad bar: How to keep greens diet-friendly and delicious

Fewer than 300 people in the study had gastric bypass surgery, a more dramatic technique in which the surgeon creates a golf-ball-shaped pouch to curb food intake. Although a reduction in cancer risk was seen with all three techniques, some experts believe that gastric bypass surgery may one day be shown to be more effective than the other two.

In gastric bypass surgery, a portion of the stomach is stapled to create the pouch and the intestines are rerouted to the new, smaller stomach. Surgeons rearrange the anatomy and that may change the hormonal milieu and affect cancer risk, Hutcher explained.

Rearranging the anatomy is thought to have an unknown effect on the body; some people with type 2 diabetes who undergo this type of surgery experience a drop in insulin resistance and other diabetes-related problems before they even lose weight. (However, this is not true for everyone; many people who undergo weight-loss surgery still have type 2 diabetes even after they lose weight.) Health.com: How two women with type 2 diabetes fared after weight-loss surgery

Weight-loss surgery safe, but sleep apnea increases risk

Weight-loss surgery isn't risk-free, but a new study suggests that in the hands of a skilled surgeon, it may be safer than previously thought. However, some people -- including those with sleep apnea or a history of blood clots -- are more likely to have problems with surgery than others, according to a study published this week in the New England Journal of Medicine.

"The overall conclusion that we reached is that bariatric-surgery safety is actually quite good," said Dr. Bruce Wolfe, a professor of surgery at the Oregon Health and Science University.

In the past, bariatric procedures have been associated with death rates of 2 to 3 percent and complication rates of up to 24 percent. However, the obesity epidemic is fueling a rise in such surgeries, prompting concerns about their safety. In 2005, 171,000 people underwent bariatric surgery, more than 10 times the number that had the procedure in 1994.

To assess the safety of such operations, Wolfe and his colleagues looked at 4,776 patients in the first month after having a bariatric procedure. They found that 4.3 percent of patients had a serious problem, such as a blood clot or needing another operation, and 0.3 percent, or 15 patients, died within a month after surgery -- a complication rate similar to other types of surgery.

Four main factors seemed to increase the risk of complications, including sleep apnea, severe obesity, a history of blood clots, and an inability to walk at least 200 feet prior to surgery. Health.com: 10 easy food swaps cut cholesterol, not Taste

Sleep apnea is a common disorder in the obese (about half of the patients in the study had the condition). Excess weight in the neck region can contribute to sleep apnea, which is characterized by snoring and the collapse of the upper airway during sleep, sometimes hundreds of times a night.

Is the fat acceptance movement bad for our health?

Deb Lemire has always been "short and square," a figure she inherited from her grandmother and passed on to her child. So when Lemire took her daughter in for a wellness visit and the well-meaning pediatrician pulled her aside to talk about her daughter's weight, the 47-year-old burst into tears "because I was the 10-year-old being told I was overweight."

She took her daughter to a nutritionist, who said her dietary habits were good. So Lemire decided not to push the issue. "I have spent my whole entire life dieting and feeling like my worth was attached to my weight," says Lemire. "I wasn't going to tell her she has to change who she is. But we're going to encourage healthy behaviors [and] not worry about translating that into a size that's 'OK.' That message is not going to come from me -- she'll get that enough from other people."

Lemire also happens to be president of the Association for Size Diversity and Health, a group that advocates that people can be healthy at any size. Her group is just one of several in a growing trend sometimes called the fat acceptance movement.

From the Dove Campaign for Real Beauty, which portrays underwear-clad women who tend to be larger than the average model, to the National Association to Advance Fat Acceptance, which fights size discrimination, many organizations and businesses are championing a new definition of beauty -- one that is not dictated by waist size.

Although most people agree that promoting super-skinny models as the feminine (or masculine) ideal isn't healthy, will the opposite -- accepting that being overweight or obese is fine -- undermine the progress being made toward heart health?

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In fact, experts have recently found that the decades-long efforts to limit one serious heart risk -- smoking -- is expected to pay off with longer life spans. Unfortunately, the rise in obesity will likely undercut that progress.

Can you be fat and fit?

Expert opinion is pretty much unanimous: Being overweight is bad for your health, particularly for your heart.

"Obesity is probably the only risk factor that has such a global negative impact on so many risk factors for the heart," says Barry Franklin, Ph.D., the director of the Cardiac Rehab Program and Exercise Laboratories at William Beaumont Hospital in Royal Oak, Michigan.

Obesity's heart disease risk factors include high blood pressure, inflammation, metabolic syndrome, and trouble with blood-fat levels, such as higher triglycerides, low HDL (good cholesterol), and high LDL (bad cholesterol). Obesity is also associated with sleep apnea.

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However, research conducted by Steven N. Blair, a professor at the Arnold School of Public Health at the University of South Carolina, suggests that some people can be overweight and healthy. In a 2007 study, he and colleagues found that unfit people over age 60 who were of normal weight had higher mortality rates during the 12-year study than people the same age with higher body-mass indexes (BMIs) who were fit (as measured by a treadmill test).

And a 2008 study found that the location of fat deposits on the body is a big factor in the health risks associated with being overweight. (Belly fat and fat deposits in the liver are bad news.)

Franklin says that studies have indeed shown that fit overweight or obese people have cardiovascular mortality rates that are lower than thin, unfit people.

Michelle May, M.D., the author of "Eat What You Love; Love What You Eat: How To Break Your Eat-Repent-Repeat Cycle," says, "We use obesity as a marker of whether someone is practicing a healthy lifestyle, but that is not a way of determining if they are making healthy eating choices, are physically active, or have economic, emotional, and social stability, which is important to longevity."

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May, who is a member of the Association for Size Diversity and Health, says, "It is easy to use a BMI and place everyone in the same box, but it is too simplistic and is not always an accurate description of someone's health."

But are such studies just an excuse for overweight people -- most of whom aren't fit -- to remain complacent about excess weight? There remains concern on the part of physicians that the rise in fat acceptance is an unhealthy trend.

Franklin says that people who are overweight or obese already have one strike against them in terms of heart health, and need to compensate by monitoring other factors like exercise, blood pressure, and blood sugar.

"I don't want to take on any specific organization...but a social movement that would suggest healthy at any size in many respects can be misleading," Franklin says. "We can't say that every overweight person is healthy."

Is body image as important as health?

But for Lemire and others, it is important to balance a healthy body image with a healthy body.

"Health at any size is helping people be as healthy as they choose to be, want to be, need to be -- as healthy as they are," Lemire says. "Everyone at any size can take care of the body they have and support their well-being."

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May says she is concerned about contributing to fear and shame within a group for which the medical community has few available solutions.

"Where else in medicine do we offer a solution -- dieting -- that is going to fail and then point to the end user and say, 'You are weak-willed; you don't have enough willpower'?" she asks. "I know many thin people who don't exercise and follow unhealthy diets."

Part of the problem is that even when people -- or their kids -- are overweight or obese, they don't think they are. In fact, 8 percent of obese people think they are healthy and don't need to lose weight (even though 35 percent of those people have high blood pressure, 15 percent high cholesterol, and 14 percent diabetes), according to a study of nearly 6,000 people presented in November 2009 at the American Heart Association meeting.

It's not clear why there's a disconnect. But with the rise in obesity, people may have a skewed perception of a "normal" weight. Right now, more than 60 percent of American adults are obese or overweight. (This map shows the states with the highest percentage of overweight people.)

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Lemire and May believe that the focus should be placed on an individual's health as much as his or her weight, and that people can make great strides just by taking small steps toward improvement.

"I think it's a given that we understand physical activity is good for your body," Lemire says. "Most people find that when they are more physically active, it makes us feel better and makes the machine run better. But we shouldn't be promoting it just on the backs of fat people."

However, people who don't think they have a health problem may be less likely to exercise, visit a physician, or talk about dietary changes with their doctor.

Stephen Nicholls, M.D., the clinical director of the Cleveland Clinic Center for Cardiovascular Diagnostics and Prevention, says it's never too late to improve your health by eating better, becoming physically active, quitting smoking, and seeing a doctor for checkups.

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However, Nicholls is still concerned that fat acceptance may send the message that being overweight isn't a health issue.

"As a population, we have moved the yardstick ourselves as what we consider to be a problem and what we don't consider to be a problem," Nicholls says. "We consume processed, high-fat, easily available food and reduce the amount of exercise and activity we perform on a daily basis. There is complacency about developing obesity, and it could suggest that we underestimate what its implications might be."

He adds, "Obesity is the single greatest public health problem we face in the U.S. today and is now spreading beyond the developed world into developing countries."

Can neck measure indicate body fat better than BMI?

Flawed, limited and inaccurate. The complaints against the body mass index are many.

Among them: The BMI, which measures weight relative to height, doesn't accurately calculate body fat. It deems athletes or muscular people to be obese and underestimates body fat in older people.

But it's inexpensive and simple, so the BMI continues to be the public health agencies' standard for assessing for obesity.

A study published Monday in the journal Pediatrics suggests another simple, straightforward measurement could be used to supplement the BMI: neck circumference.

A wide neck circumference is associated with obesity-related conditions such as sleep apnea, diabetes and hypertension, according to research. Neck circumference has been explored in studies for potential obesity and heart problems in adults.

Lead author Dr. Olubukola Nafiu and his colleagues examined 1,102 children and recorded their heights, weights and neck circumferences to determine whether this measurement could be another way to assess obesity in children.

They measured necks using a flexible tape at the most prominent part of the neck. For older males, that area was the Adam's apple.

The authors found that a 6-year-old boy with a neck circumference greater than 11.2 inches was 3.6 times more likely to be overweight or obese than a peer below that level. Using the data, they devised neck measurements at which children could be at higher association with overweight and obesity.

Taking such a measurement is inexpensive, easy and could be predictive of health problems such as sleep apnea, Nafiu wrote in the article. He's an assistant professor of pediatric anesthesia at the University of Michigan School of Medicine Health, Ann Arbor.

One of BMI's shortcomings is that it "does not accurately define central body fatness," Nafiu said. Neck circumference could give better clues to body fat composition, he said.

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Studies have shown that regional adiposity, which is fat collected around the midsection, is often a good indicator for obesity-related complications, including hypertension, diabetes and heart disease. The correlation between regional adiposity and a high neck circumference is strong, said Nafiu. This could give doctors more information than BMI alone.

"We've been using BMI to advise parents and patients for making healthy choices," he said. "Unfortunately, often we tell someone their BMI is 27 or 30, most of the time it doesn't mean much. To tell you that your neck is wide, these are some of the risks associated to it -- that we feel people would be able to relate to it better than BMI."

The idea of using circumferences of various body parts has been around for awhile, said Jim Pivarnik, director of the Center for Physical Activity and Health at Michigan State University.

"It's not widely used," he said. "It doesn't mean it's not correct, but it's not widely used."

One of the challenges is the difficulty of accurate measurements. Waist circumference "is harder to measure than you might think," said Dr. Cora Lewis, a professor of medicine and public health at the University of Alabama at Birmingham.

"There's the issue of figuring out where you measure," she said. "If someone is obese, should the waist measurement come under or over the fold?"

Despite its flaws, Lewis said the BMI still gives information.

"It's a good place to start," she said. "Lots of people bash it, but what else are we going to use?"

The alternatives, such as air chambers that measure a person's mass and volume to calculate the composition of muscle and fat and underwater scales, are expensive and impractical, Pivarnik said.

The neck circumference could an initial screening tool someday, Nafiu said. But he wrote additional studies are needed to evaluate how useful it is in detecting abdominal fat.

"If a neck circumference is above what you regularly see, that raises a red flag," he said. "You want to ask further questions, then see other indices of body fat -- BMI, abdominal circumference and other parameters."

Is it baby fat -- or obesity?

Desani Marshall was never really overweight, but she was always a little big for her age. During a checkup at age 4, her doctor pointed out to her mother that Desani was gaining weight more rapidly than he thought was normal. Six months later, she was still putting on pounds at a rapid pace -- a strong predictor of future obesity.

"I didn't take it seriously; I didn't think it was that bad," says Desani's mother, Caryl Marshall, of New York City. "But then he showed me the growth chart. At the rate she was gaining, what really made me take it more seriously was what the future could be."

Now 7, Desani is gaining weight at a normal pace, thanks in part to dietary changes, such as cutting out soda, that Marshall has implemented. "Everybody would look at her and say, 'She's so skinny. Why?'" Marshall says of her daughter's regimen.

In some ways, Desani's success story is an exception. Across the country, childhood obesity has only gotten worse. More than 20 years after it was first described as an epidemic, 17 percent of American children and adolescents are obese, triple the rate in 1980, and nearly one-third are overweight, according to the latest government data.

Alarming statistics such as these have prompted government agencies, schools, and nonprofit organizations to launch a barrage of anti-obesity programs in recent years.

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Their sense of urgency is not shared by all parents, however. In fact, studies have consistently shown that parents tend to underestimate their child's weight and the health risks associated with being too heavy.

In a 2006 study that surveyed the parents of obese children, only one-half recognized that their child was overweight, and less than one-third said they were "worried" about their child's weight. In another survey, only 38 percent of parents had taken steps, or were planning to take them, to help their obese child lose weight.

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Several factors may be contributing to this indifference among parents, experts say. Some parents believe their child's excess weight is just "baby fat," for instance, and some may simply be in denial. Or it could be that parents have concluded their kid is normal after eyeballing his or her overweight peers.

"Because so many children are overweight and obese ... they don't stand out as much as they would have 20 or 30 years ago," says nutritionist Elisa Zied, a registered dietitian and spokesperson for the American Dietetic Association. "I almost see a lack of concern with some parents."

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Parents should be concerned. Although some overweight kids do outgrow their baby fat, roughly two out of three are likely to grow up to be obese adults, according to a 2009 study by the U.S. Centers for Disease Control and Prevention (CDC). Childhood obesity, moreover, is associated with a slew of serious health problems, including diabetes, asthma, heart disease, and depression.

How do you know if your child's chubbiness is baby fat or a serious health problem? You can't always tell just by looking, and you can't always count on pediatricians to broach the subject. But you can take matters into your own hands and adopt habits that will keep your child as healthy as possible.

You can't trust your eyes

Most parents probably feel pretty confident that they know whether their child is overweight or not. The research tells a different story: A large proportion of the parents of overweight children -- and especially mothers, who are surveyed more often -- do not perceive their children as overweight. In some studies, the percentage of parents who don't realize (or won't admit) that their child is overweight has been reported to be as high as 80 percent to 90 percent.

It's not entirely clear what accounts for this disconnect. For starters, many parents define obesity differently than health professionals do, and distrust the growth charts used by pediatricians.

In a focus group discussion that was excerpted in the journal Pediatrics in 2001, one mother of a preschooler defined an obese person as someone who "can barely walk." Other mothers denied that their children were fat or overweight, and instead used words like "big-boned," "chunky," and "solid" to describe them.

Susan Carnell, Ph.D., a research fellow and childhood obesity expert at the New York Obesity Research Center, attributes the failure of parents to accurately assess their child's weight to changing social norms. Not only are kids heavier than ever before, but roughly two-thirds of adults are also overweight, and parents who are overweight themselves are less likely to identify their children as overweight, Carnell notes.

"We gain many of our perceptions from comparison with peers," she says. "So if we compare a healthy-weight child with their overweight classmates, we may even think they are too skinny and try to feed them up."

Social values and beliefs may also distort a parent's perception. Parents are more likely to overestimate the weight of their daughters, for instance, perhaps because they feel it is less acceptable for girls to be heavy. Similarly, some studies suggest that parents of different ethnicities and cultural backgrounds have different conceptions of body type and overweight.

The doctor may not bring it up

If you're waiting for your child's pediatrician to tell you that your child is a bit heavy, don't hold your breath. In spite of the myriad health risks associated with childhood obesity, pediatricians often fail to screen for it during annual checkups and office visits.

In a recently published survey of its members conducted by the American Academy of Pediatrics (AAP), virtually every pediatrician said they measured height and weight during checkups.

But just 52 percent use those figures to calculate body mass index (BMI), a simple ratio of height-to-weight that provides a rough yet useful snapshot of whether a child is overweight for his or her age. (The CDC defines overweight as a BMI in the 85th percentile or above, and obesity as the 95th percentile or above.)

Even if they do feel that a child is overweight, many pediatricians are hesitant to say so, perhaps because they think it's a touchy subject. In the AAP survey, only 59 percent of pediatricians said they believe that families want to discuss weight.

"I think some doctors are reluctant to bring up weight because they are not trained to deal with it sensitively," says Carnell. Discussing a child's weight with parents in the wrong way -- by implying that they are to blame, for instance -- can make parents "feel guilty and defensive," she adds.

Doctors may also adopt a hands-off approach to weight because they feel there's little they can do. Less than one-quarter of the pediatricians in the AAP survey believed that there are effective treatment strategies for overweight and obesity.

"We all have strategies we use that can make a difference with a certain proportion of kids," says Eugene Dinkevich, MD, the division chief of general pediatrics at SUNY Downstate Medical School, in Brooklyn. "But it's not like an ear infection where you can give someone an antibiotic and they're better."

Pediatricians only set aside about 15 minutes for a regular checkup, Dr. Dinkevich says, and they have to pick and choose which topics to discuss with parents in that time. Doctors must ask themselves, "What am I competent to talk about, and if I talk about it, will it make a difference?" he says. For far too many doctors, he adds, obesity treatment and prevention don't fall into that category.

New guidelines for childhood obesity screening might help reassure pediatricians. In January, the U.S. Preventive Services Task Force, an independent panel of experts that advises the federal government on preventive care, released new guidelines that urge doctors to routinely calculate the BMI of children between the ages of 6 and 18. The guidelines also say that children who qualify as obese should be referred to various interventions, such as nutritional counseling or physical activity programs.

"In 2005, we said you can screen kids, but we had insufficient evidence of any effective therapy for weight loss," says task force chairman Ned Calonge, MD, referring to the previous guidelines. "Now we have evidence that shows you can get modest weight loss through these intensive programs."

Too few docs tell patients they're overweight

Many people who are overweight and obese either don't realize it or are in denial -- and too few doctors are setting them straight, according to a new study in the Archives of Internal Medicine.

Researchers analyzed data on roughly 5,500 people who took part in government health surveys between 2005 and 2008. One-third of the obese participants and 55% of overweight participants had never been told by a doctor that they were overweight, the study found.

If a doctor did comment on a patient's weight, it seemed to make an impression. Nearly 20% of obese people whose doctors hadn't brought up their weight described themselves as "not overweight," compared with just 3% of those whose doctors had addressed their weight. Obese and overweight patients who discussed the issue with doctors were also more than twice as likely to have tried to lose weight in the previous year.

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"If people are told by their doctor that they are overweight, it corrects their perception," says the lead author of the study, Robert Post, M.D., research director of the Virtua Family Medicine Residency in Voorhees, New Jersey.

Overweight is defined as having a body mass index between 25 and 29, and obesity is defined as a BMI of 30 and up. (BMI is a rough estimate of body fat based on the ratio of a person's height and weight.)

Doctors may be reluctant to broach the subject of weight for a number of reasons, Post says. For instance, busy physicians might not want to fall behind schedule by adding another topic to their list of things to discuss during an appointment. And many doctors have negative attitudes toward their heavier patients, whom they see as unlikely to stick to a diet and exercise program, he adds.

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The researchers weren't surprised by the high percentage of overweight people who thought their weight was normal, as several studies in recent years have found comparable -- or higher -- rates. A study published last year that used similar data from government surveys showed that 23% of overweight women and 48% of overweight men considered their weight to be just right.

Post and his colleagues chalk this up to what they call the "'norming up' of society." Roughly two-thirds of U.S. adults are now overweight or obese, and as Americans have grown heavier, the perception of what constitutes a normal weight has changed as well, Post says.

In fact, most of the overweight study participants accurately estimated their BMI. But many didn't see their weight as unhealthy or recognize the need to shed some pounds.

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Although it might seem obvious that excess weight is unhealthy, being reminded of this by a doctor can be an effective wake-up call, says Robert B. Baron, M.D., director of the weight management program at the University of California San Francisco.

In an editorial accompanying the study, Baron notes that studies have shown that smokers whose doctors remind them of how unhealthy the habit is and encourage them to quit are more likely to do so successfully than those whose doctors stay mum. Simple reminders and encouragement to lose weight could have a similar effect on overweight and obese patients, he says.

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Baron proposes calculating BMI and entering it on a patient's chart at every doctor's office visit, as is done with blood pressure and other vital signs. "This is very, very easy to do," Baron says. "If it were required or strongly suggested, it would not be very onerous.... We need to be as aggressive as we were with smoking cessation."

Study: Most obese moms, kids underestimate their weight

Roughly two-thirds of adults and one-third of children in the U.S. are now overweight or obese. Aside from contributing to rising rates of diabetes and other chronic illnesses, this widespread weight problem also appears to be changing our perception of what's considered heavy.

As overweight and obesity have become more common, those who are carrying unhealthy extra pounds are increasingly likely to see their weight as normal, and are therefore unlikely to feel the need to shed some of those pounds.

The latest evidence for this trend was presented Wednesday at an American Heart Association conference in Atlanta, where Columbia University researchers reported the preliminary results of a study that found that overweight mothers and children tend to underestimate their own -- and each other's -- weight.

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"A lot of their misperception has to do with the fact that overweight and obesity is becoming the norm," says the lead author of the study, Nicole E. Dumas, M.D., an internal medicine resident at Columbia University Medical Center, in New York.

The study included 222 mostly Latino mothers and children who were recruited at a children's health clinic in an urban setting. The research team interviewed the participants about their medical history and social background, and also measured their height, weight, and body mass index.

Just under two-thirds of the mothers were overweight or obese, as were nearly 40% of the children, who ranged in age from 7 to 13. The vast majority of the overweight people weighed more than they thought they did -- and the heavier they were, the more likely they were to underestimate their weight.

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Eighty-two percent of the obese women underestimated their weight, compared with 43% of overweight and 13% of normal-weight women. Likewise, 86% of overweight or obese children failed to correctly estimate their weight, compared with just 15% of normal-weight children.

"There was a trend that showed that as women became more and more overweight, and then obese, the larger the misperception of true body weight was," says Dumas. "Unfortunately, we found this was the case with the children as well."

The participants' misperceptions were not limited to how they viewed themselves: Nearly half of the mothers who had an overweight child believed their child's weight to be normal. And even though more than 80% of the women were overweight, only 41% of the children thought their moms needed to lose weight.

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Moreover, when the children were presented with a series of cards bearing silhouette images of body types and were asked to select the "ideal" or "healthy" size for their mother, they tended to pick body types that were, in fact, unhealthily large.

Robert Eckel, M.D., a cardiologist and professor of medicine at the University of Colorado Denver, says the study was too small and too ethnically homogenous to support any firm conclusions. "With this fairly small sample, it's hard to weed out any information that is generalizable," says Eckel, who was not involved in the research. "However, it's clear that perception was skewed."

Dumas acknowledges that her findings may not apply to the U.S. population as a whole, although she points out that other studies have found similar trends among African Americans and Caucasians. The study does, however, shed much-needed light on how weight perception functions across generations, she says.

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"In order to target the obesity epidemic, we need to improve perceptions of body weight and create healthy image goals," Dumas says. "But how do we change perceptions? That's the big question."

Dumas presented her findings at the American Heart Association's annual conference on nutrition, physical activity, and metabolism. Unlike the studies published in medical journals, the research presented at the meeting has not been thoroughly vetted by other experts.