Home / Cover Story / Redefining the war on obesity

Redefining the war on obesity

Obesity Researcher Gary Foster, Ph.D.
Obesity Researcher Gary Foster, Ph.D.

By Christopher Guadagnino, Ph.D.

Curbing the rise of obesity rates among Americans has overtaken smoking as the putative public health priority, with government and non-profit health agencies promoting frequent anti-obesity warnings. One of the latest reports, titled F as in Fat: How Obesity Policies Are Failing In America 2008, released last month by the Robert Wood Johnson Foundation and the Trust for America’s Health, declares obesity to be one of the most serious health problems in the U.S. The report notes that adult obesity rates have doubled since 1980 – from 15 percent to 30 percent, that two-thirds of adults are now either overweight or obese, that childhood obesity rates have nearly tripled since 1980 – from 6.5 percent to 16.3 percent, and that the obesity epidemic adds billions of dollars in health care costs. The report castigates federal, state and local governments for failing to address the obesity epidemic in proportion to the threat that it poses.

Counterposing the prevailing “war on obesity” is a body of literature – including some recent studies that have been widely reported in the press – that complicates the issue by casting doubt on some of the most basic assumptions about the dangers of being overweight and what to do about it, namely, that being overweight is unhealthy, and that people can lose significant amounts of weight and keep it off if sufficient interventions are put into place.

Many physicians express a lack of confidence in treating obesity, indicating in surveys that they expect patients to be unmotivated and non-compliant with treatment, that those who do stay in treatment won’t lose much weight, and those who do lose weight will likely regain it, according to a research report released late last year by the George Washington University School of Public Health and Health Services. The report, Re-Visioning Success: How Stigma, Perceptions of Treatment, and Definitions of Success Impact Obesity and Weight Management in America, notes that there is no consensus today among patients, providers and researchers on what constitutes successful weight loss, as overweight and obese people and their health care providers often have unrealistic weight loss goals and very few succeed in achieving them. A major barrier in preventing and treating obesity, the report indicates, is a sense of futility and pessimism – the perception or assumption that nothing works, and that treatments produce only modest amounts of weight loss and seem hardly worth the effort.

Obese individuals themselves are often unrealistic about weight loss, defining success as losing a large amount of weight and hoping for unachievable results from obesity treatments, according to Gary Foster, Ph.D., director of the Temple University Center for Obesity Research and Education, and professor of medicine and public health at Temple University School of Medicine. In surveys, obese patients seeking weight loss treatments indicate a 38 percent loss in body weight as their ideal, a 25 percent loss as something they would be happy with, and a 17 percent loss as disappointing, Foster notes.

Treatment programs traditionally counsel individuals to temper their expectations, says Foster. Obesity is a chronic refractory condition, he says, and patients can realistically expect to lose, on average, seven to nine percent of their body weight over the first six months at an academic weight loss center, less than a third of which is typically regained at 18 months, but as much as 80 percent of which is regained in five years.

While bariatric surgery has been successful in assisting obese persons lose and maintain significant amounts of weight loss, the George Washington University report notes that those procedures are typically only available to people who are morbidly obese or who are already suffering from related medical comorbidities such as hypertension and diabetes. For the majority of overweight and obese Americans, clinically effective weight loss interventions are scarce.

Those mixed messages from anti-obesity advocates and from research questioning the efficacy of medically-backed weight loss treatments raise questions about what role physicians and medical institutions can or should play in combating obesity and how they can best help their patients, a sizable percentage of whom will be overweight and obese, and who may express frustration with conflicting weight loss information they hear.

A consensus among experts interviewed for this article is that physicians play a central role: helping the patient redefine success. Encouraging overweight and obese patients to sustain a modest, but realistic weight loss of only a few pounds, they say, can bring significant health improvement even in the absence of much cosmetic change.

A consistent and meaningful definition of success is lacking in research and public health arenas, notes the George Washington University report, and society has yet to embrace a modest, but achievable goal for obesity intervention that focuses on improved health outcomes rather than weight reduction to some pre-set number, like optimal body mass index (BMI). “The paralysis resulting from a sense of futility and the perceived lack of ‘effective’ treatments may actually be a mismatch between the goals of people trying to lose weight and those whose goal it is to improve health and the lack of a cohesive system that integrates both views,” the report concludes.

Obesity Impacts

The incidence of obesity in the U.S. is rising, stretching into earlier years in childhood, and producing serious comorbidities.

BMI, a ratio of weight to height, is a common measure of obesity and overweight: adults with a BMI of 25 to 29.9 are considered overweight, while individuals with a BMI of 30 or more are considered obese, notes the Trust for America’s Health’s F as in Fat report. Before June 1998, when the National Institutes of Health (NIH) adopted the current optimal weight threshold, the federal government defined overweight as a BMI of 28 for men and 27 for women. Many experts recommend assessing an individual’s health using factors in addition to BMI, such as waist size, waist-to-hip ratio, blood pressure, cholesterol level and blood sugar, the report notes.

The report lists multiple contributors to the rising incidence of obesity in the U.S., including food choices (adults consumed approximately 300 more calories daily in 2002 than they did in 1985); communities not designed for physical activity (e.g., lack of public transportation options, inconvenient or unsafe walking areas); greater marketing, advertising and affordability of less nutritious foods; more meals – many of them high in calories – eaten outside of the home; workplaces that limit or discourage physical activity; limited health insurance coverage for obesity-prevention services; “electronic culture” options for entertainment and free time; and increased risk factors for obesity and related diseases in children with obese parents.

The health impacts of obesity and overweight are well-documented, and the report cites a round-up of research to that effect. More than 80 percent of people with type 2 diabetes are overweight, while diabetes is the seventh leading cause of death in the U.S. and accounts for 11 percent of all U.S. health care costs. People who are overweight are more likely to suffer from high blood pressure, high levels of blood fats, and high LDL (“bad”) cholesterol – all risk factors for heart disease and stroke. Roughly 30 percent of cases of hypertension may be attributable to obesity, and in men under the age of 45, the figure may be as high as 60 percent. People who are overweight may increase the risk of developing several types of cancer, while approximately 20 percent of cancer in women and 15 percent of cancer in men are attributable to obesity. Obese adults are more likely to suffer from depression, anxiety and other mental health conditions than normal weight adults. Obese individuals (BMI=30) are 83 percent more likely to develop kidney disease than normal weight individuals (18.5<BMI<25), while overweight individuals (25< BMI=30) are 40 percent more likely to develop kidney disease. Obesity is a known risk factor for the development and progression of knee osteoarthritis and possibly osteoarthritis of other joints.

Questioning Assumptions About Obesity

While no one seriously questions that significant comorbidities are associated with obesity, recent studies add to a body of literature suggesting that the health impact of being overweight and moderately obese has been greatly exaggerated, that people’s weight is largely biologically determined within a fairly narrow range, and that changing diet and increasing exercise has little long-term influence on weight loss.

A study published last month in the Archives of Internal Medicine concluded that half of overweight adults may be heart-healthy. The analysis of nationally representative government surveys from 1999 to 2004 found that about 51 percent of overweight adults had mostly normal levels of blood pressure, cholesterol, triglycerides and blood sugar, while almost one-third of obese adults had abnormal levels on none or only one of those measures. The study also found that about a fourth of adults in the recommended-weight range had unhealthy levels of at least two of the measures.

A second study, appearing in the same issue of Archives, concluded that even in obesity there can be metabolically benign fat distribution not accompanied by insulin resistance and early artherosclerosis.

A study published in the Journal of the American Medical Association in 2005 highlighted what researchers termed an “obesity paradox.” Using statistical methods to factor out causes other than obesity that could lead to death – smoking, age, chronic diseases – and using reliable national data comprised of actual measured heights and weights, researchers were left with a “U-shaped” mortality curve in which there was less mortality risk from being overweight relative to normal weight, little mortality risk from being obese, and higher mortality risk from being extremely obese or underweight.

Critics have questioned society’s fixation on the anti-obesity movement. Gina Kolata, science reporter for the New York Times, in her book Rethinking Thin, cited research indicating that people’s weight is largely biologically determined, and that decades of studies consistently show that very few people lose substantial amounts of weight and most never achieve their goal of permanent and substantial weight loss. At best, dieters can sustain an average of five to ten percent weight loss.

For example, wrote Kolata, an eight-year, $20 million project sponsored by the National Institute of Health’s National Heart, Lung, and Blood Institute, published in the American Journal of Clinical Nutrition in 2003, followed third graders in 41 elementary schools in the Southwest, mostly Native Americans at great risk of obesity. The two-year intervention included healthy and low fat breakfast and lunch (representing one-half of their total calories each day), regular instruction to children and families on how to choose healthy foods, exercise breaks every day and an hour of real exertion at least three times a week. The study found no change in body weight of children compared to the control group.

A study published in Archives of Pediatrics in 1999, also sponsored by NIH, which Kolata described as the largest school-based randomized trial ever conducted, involved third graders from 96 schools in CA, LA, MI and TX who were given healthy food, nutrition instruction and extra physical activity until fifth grade. Children in the schools with special programs learned their lessons, ate less fat, exercised more, retained their knowledge for years afterward, wrote Kolata, but their weights after three years were no different from the control group.

A study in the New England Journal of Medicine this July highlighted the difficulty of weight loss even among the most dedicated dieters. A tightly-controlled, two-year randomized trial study (with an unusually high proportion of subjects – 85 percent – adhering to the study’s diets throughout the entire two years) found that moderately obese subjects who adhered to low-carbohydrate, Mediterranean, and low-fat diets for two entire years lost only six to ten pounds. But even that modest weight loss led to improvements in cholesterol and diabetes biomarkers, and the researchers suggested that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions.

Some researchers believe that genetic predisposition may play a major role in obesity, and is a large obstacle to treatment. If true, then those with such genes “catalyze the possibility” of becoming obese with easy access in today’s society to plenty of calories for their genes to direct them to become fat, according to Jules Hirsch, M.D., professor emeritus of The Rockefeller University and physician-in-chief emeritus of The Rockefeller University Hospital in New York City. “If you have a gene for obesity, you now have the maximum possibility of becoming obese,” given our society’s wealth, abundance of foods, fast foods, sedentary lifestyles and other factors, says Hirsch. A life-long obesity researcher, Hirsch is currently investigating the genetic obesity hypothesis by studying infantile obesity effects in mice.

“People who eat and exercise the same don’t weigh the same,” says Foster, noting that it is harder for biologically predisposed people to lose weight. “It is not a fair game. For some, it is unrealistic to try to lose even five percent of their body weight,” he adds.

Inherited hormonal mechanisms may account for diet-resistant obesity. For example, diet-induced weight loss in humans results in a decrease in the body’s concentration of leptin, an appetite-suppressing hormone discovered in 1994 by Jeffrey M. Friedman, M.D., Ph.D., professor at the Rockefeller University and Director of the university’s Starr Center for Human Genetics. Because it is secreted by adipose tissue, increased fat mass increases leptin levels, which in turn reduces appetite and body weight; while decreased fat mass leads to a decrease in leptin levels and an increase in appetite and, ultimately, body weight. By this mechanism, weight is maintained within a relatively narrow range, and genetic defects in the leptin gene or its receptors are associated with severe obesity in animals and in humans, according to Friedman’s research abstract on the Howard Hughes Medical Institute website. Reduction in leptin concentration – which is beyond the behavioral control of individuals – may explain the high failure rate of dieting, Friedman believes, as low leptin is a potent stimulus to increased appetite and weight in animals and humans.

“People have underestimated the biological back-up mechanisms that make it extremely difficult to lose more than seven to ten percent of body weight. If you induce weight loss, you turn on these counter-regulatory systems in the gut and central nervous system that govern appetite and energy expenditure, and control body weight,” says Stephen Schneider, M.D., an endocrinologist, and professor of medicine, UMDNJ- Robert Wood Johnson Medical School.

Obesity researchers therefore believe that the anti-obesity movement tends to place too much emphasis on overall body weight, ignoring a more complicated relationship between body fat and its metabolic impacts. “It’s not how fat you are,” says Schneider, “but rather, what the obesity is doing to you.”

Redefining Success

Even though most overweight or moderately obese patients rarely sustain more than a five to ten percent weight loss through non-surgical clinical treatments, experts believe that is an important achievement, and continue to study the metabolic changes that it brings. Interventions, they say, should be targeted according to how fat is distributed in the body, and physicians should help patients reach modest – but achievable – goals for weight loss, which can greatly improve health even in the absence of much cosmetic slimming or an “optimal” BMI.

Even anti-obesity advocates have begun to acknowledge the importance of redefining success as modest, incremental intervention. The Trust for America’s Health declares in its F as in Fat report that “too many Americans, including health practitioners, have an unrealistic expectation about how much weight loss is enough to achieve meaningful change. The research community should redefine successful weight loss as it pertains to ‘controlling or reducing health risks and costs,’ instead of meeting some unrealistic standard set by society.” For individuals, the report notes, “there is increasing evidence that substantial weight loss is not needed to change health outcomes for obese individuals; in fact, as little as a 5 to 10 percent weight loss can reduce the risk factors for some diseases, including diabetes and some cardiovascular diseases.”

“Being overweight, for most people, is not unhealthy. The acceptable BMI used to be 27, then epidemiologists lowered it to 25. I see that as arbitrary,” says Madelyn Fernstrom, Ph.D., founding director of University of Pittsburgh Medical Center’s Weight Management Center. A reasonable goal for physicians is to encourage healthy overweight people to be weight-stable, she says: for a patient with a BMI of 29 and normal blood work, the best advice might simply be not to gain any weight. “The opening dialogue should be whether patients should lose weight or be weight-stable,” says Fernstrom.

Physicians can refine their targeting of obesity interventions by explaining to overweight and obese patients that “obesity comes in different flavors” – belly versus hips and buttocks – and some obese persons do better than others. Patients with excess abdominal fat do more poorly and have more medical complications, including diabetes – the chief menacing complication of obesity, says Hirsch. Determining whether a patient is insulin resistant, or has excess liver fat, represents further important clinical refinement to defining obesity in a physician’s patient population and requires frequent and vigilant monitoring of overweight or obese patients’ glucose metabolism and other screenings, Hirsch notes.

Large waist circumference indicates the more visceral and metabolically active fat, and its measurement is critical for stratifying the risk of diabetes, fatty liver, cardiovascular disease and sleep apnea, says Christopher Still, D.O., director of Geisinger Health System’s Obesity Institute, and director of its Center for Nutrition and Weight Management. Weight loss interventions may be especially warranted for men with a waist measurement over 40 inches, and women over 35 inches, he notes. The gynoid, or pear-shaped fat distribution around the hips and buttocks may even be cardio-protective, notes Still, producing higher concentrations of high-density lipoprotein (“good”) cholesterol which enables lipids like cholesterol and triglycerides to move through the blood stream back to the liver for excretion or re-utilization. That said, it is bad to be obese for other medical reasons, including degenerative arthritis, he adds.

A clinical paradox is that women seek the services of weight loss clinics at a ratio of four-to-one over men, even though men have by far the more adverse abdominal fat distribution, says Foster, and he suggests that a greater focus on overweight and obesity in men with greater than 40-inch waist size may be warranted.

“Treatment stinks,” Hirsch declares, noting that medication or diets – even those administered at academic-based weight loss centers, which promote different types of diets, behavior modification therapy and other treatments – make no lasting improvement 80 to 90 percent of the time. The type of diet doesn’t make much difference in outcomes, either, he believes. Even long-term outcomes of bariatric surgery are questionable beyond five or six years, as data are poor and a great number of research subjects are lost to follow-up studies, says Hirsch.

“There is good evidence that what matters most for long-term weight control is a change in physical activity and moderate reduction of caloric intake – by any dietary means a person wants – to lose five to ten pounds. Those lifestyle changes are key diabetes interventions, and even a surprisingly small loss of weight can lower insulin resistance,” says Hirsch.

Patients at the cusp of being at risk of type 2 diabetes can reduce by 60 percent their chance of getting the disease with as little as an 8.8-pound weight loss, notes Foster, who says further research is underway to determine whether certain types of diets are best suited to certain metabolic improvements – such as lipid, blood pressure or glycemic control. “The data are not there yet, but the more important clinical implication is that the best diet is the one the patient can adhere to. If we can get weight loss reliably and predictably, then we can fine-tune them. Until then, it is splitting hairs,” to endorse one diet over another, Foster believes.

Some experts believe that targeting insulin resistance with medication, such as glitazones, can be effective at redistributing body fat away from the liver and muscles – resulting in little weight loss, but significant metabolic improvement, according to Schneider, who also says it is not yet known whether there are certain diets that will target that kind of fat more effectively. “We still need to find out why and how certain types of fat distribution cause insulin resistance. Then, we can target drugs more effectively,” adds Schneider.

Physicians can adopt simple and effective interventions for overweight and obese patients seen in their office. “Ask three to four minutes worth of questions, then negotiate a change with the patient – something he or she can sustain on a life-long basis,” says John Buse, M.D., president, medicine and science, of the American Diabetes Association (ADA). Questions can include: “Do you snack? What do you eat? How much walking do you do? Do you exercise?” Buse notes that many health insurance plans don’t cover dietitian services for patients without a diagnosis. A major barrier, says Buse, is taking a monolithic approach to diabetes management, like “don’t eat any white food,” instead of individualizing lifestyle choices for patients. “Positive reinforcement is key,” notes Buse, “then ‘seducing’ people into more favorable lifestyles during serial office visits.” Ideally, the ADA recommends 30 to 60 minutes most days of moderate physical activity, together with trained counseling, adds Buse.

For a 250-pound person, a 500-calorie deficit per day can lead to a one-pound-per-week weight loss, says Still. A simple prescription can be offered to everybody, irrespective of body shape, he says: avoid all caloric beverages – including fruit juices –which can add 1,000 calories per day, and increase exercise activity.

Moderate exercise, combined with moderate caloric reduction, can achieve some cardiovascular improvement even without significant long-term weight loss, says Howard Kramer, M.D., a private cardiologist with Cardiovascular Associates of Southeastern Pennsylvania. He promotes the “Ten Thousand Steps to Better Fitness” program and advises his overweight patients to buy an inexpensive pedometer to count 10,000 steps – about three miles of walking – per day, while he also recommends programs such as Weight Watchers, which uses a convenient point system to make caloric tracking easy.

Even though the ability to lose weight and keep it off is very difficult, Foster says it would be “therapeutic nihilism” not to try, that a five to ten percent loss of weight is a therapeutic success, and that patients must be encouraged to set small but attainable goals – five, six or seven pounds at a time.

Directions for future obesity research include studying the effects of various coaching and counseling behavior approaches to manage obesity as a long-term condition, rather focusing on short-term fixes, says Foster. Increased frequency of contact with health care practitioners appears to be important, as obese patients don’t do well when left unmonitored, he notes. What works best appears to be self-monitoring – of what you eat, how you move, and what you weigh; accountability – getting weighed on a regular basis; and structured approaches to portion control that makes caloric adherence convenient and uncomplicated, adds Foster.

Obesity researchers are currently investigating the biological processes of obesity, including the hypothalamus and central nervous system mechanisms of fat storage, using molecular genetic techniques, says Hirsch, while he believes future research must study obesity’s developmental sequence – tracking the genetic, environmental and behavioral contributors to the fat sequestration mechanism during infancy and childhood. By adulthood, says Hirsch, that mechanism appears to be set to maintain a person’s weight within 10 to 15 percent body weight range, and any weight loss treatment is attempting “to buck a very fundamental and complicated body control mechanism.”

Obesity researchers are also investigating the hormonal changes in the gut and brain that follow bariatric surgery and lead to significant resolution of diabetes, high blood pressure, fatty liver, sleep apnea and other obesity-related comorbidities, with the hope of being able to mimic those changes without surgery, using pharmaceutical or endoscopic procedures, says Still.

“If you have a ‘war on obesity,’ you have to know who the enemy is,” says Hirsch. “Is it fat people? Schools? Parents? The enemy is ignorance – we don’t know yet how and why obesity comes about.”

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.