Management of Obesity: A Challenge for the Family Physician
By Sherika Newman, DO; Pablo J. Calzada, DO, MPH
Defining the Obesity Epidemic
The prevalence of overweight obesity has increased sharply for both adults and children during the past 30 years. Since 1976–1980, the prevalence of obesity among U.S. adults has approximately doubled. In 2005–2006, more than 34 percent of adults age 20 years or older were obese. The prevalence of obesity among children age 2–5 years increased from 5.0 percent during 1976–1980 to 13.9 percent during 2003–2004. During the same period, the prevalence increased from 6.5 percent to 18.8 percent among young people age 6–11 years, and 5.0 percent to 17.4 percent among those age 12–19 years.1
The obesity epidemic has become a major disease of public health priority in the United States. The American population has experienced a significant increase in its obesity rate during the last three decades (Table 5). Today, it is estimated that over 60 percent of adults are either overweight or obese.2 This epidemic poses immediate and long-term health risks with potential for significant reduction in life expectancy to all Americans.
The National Health and Nutrition Examination Survey3 (NHANES) estimated that 66.3 percent of the U.S. population over 20 years old is overweight or obese (Tables 1 and 2), 17 percent of adolescents age 12-19 are overweight, and 19 percent of children age 6-11 are overweight.
There are several definitions for obesity. Percent of Body weight was previously the measuring criteria, which can be performed using a Dual Energy X-ray Absortiometry (DEXA) scan, a chamber using air displacement, or underwater weighing. These methods are not practical and have been replaced with BMI and waist circumference. BMI evaluates weight relative to height by calculating weight (kg)/height (m2). This correlates with total body fat and increased risk of morbidity and mortality, and therefore is the measurement most used in practice.4
Since body fat distribution around the abdomen is an independent risk factor for obesity and its cardiovascular disease repercussions, waist circumference is also used to define obesity and its health-related complications.1 A waist circumference >35 inches in women and >40 inches in men are the defining criteria for obesity.
Children and adolescents are measured using BMI–for-age. After calculating the BMI for children and teens the result is plotted on the Centers for Disease Control (CDC) BMI-for-age chart. This chart compares the BMIs of children of the same age and sex. Overweight is defined as a value greater than the 95th percentile, and being at-risk for overweight is a value that falls between the 85th and 95th percentiles. The CDC and American Academy of Pediatrics recommend screening begin at age two.1 Further work-up is needed if a child is found to be overweight or at risk for being overweight.
Etiology
Although not the only important factor, the consumption of more calories than needed without the corresponding energy expenditure is a major cause of the development of obesity. This increased consumption causes long-term positive energy balance which is stored as fat. Obesity has risen over the years partly because our portion sizes have increased with time.5 It is estimated that caloric intake has increased by 12 percent per person per day from 1985-2000.4
Other etiologies of significance include body habitus, hereditary and familial determinants, environmental conditions, behavioral and mental health influences, the presence of low rate of fat oxidation and low sympathetic activity, low levels of plasma leptin, multiple psychological stressors, low socioeconomic status, low resting metabolic rate (RMR), and the use of medications.
Several studies have shown that obese people have increased serum leptin secondary to resistance from excess signaling or increased adipose tissue.8 Leptin is released by adipose tissue to signal satiety, which causes the hypothalamus to decrease the appetite and increase metabolism. The leptin receptors are down regulated in obese patients who overeat, therefore causing increased circulating leptin levels. The interaction of all these etiological factors may be contributing synergistically to the significant increase in the current obesity epidemic.5
Risk Factors of Obesity Associated with Morbidity and Mortality
Obesity contributes negatively to virtually every medical circumstance. However, there are three major high risk diagnoses associated with obesity. Coronary Artery Disease (CAD), Type 2 diabetes mellitus, and sleep apnea are significantly linked to increased morbidity and mortality in obese individuals. Obesity increases the deleterious effect other important risk factors have on the overall health status, including age (>45 years old in men, >55 in post-menopausal women), hypertension (HTN), low-density lipoprotein (LDL) >160, high-density lipoprotein (HDL) <35, impaired fasting glucose, premature CAD, osteoarthritis, gallstones, and stress incontinence. Patients with three or more of the above listed risk factors have a higher risk of morbidity and mortality from obesity. Patients with two or more risk factors with a BMI of 27 to 29 should be evaluated for a weight loss program or therapy. Obese patients also are at a significantly increased risk for heart disease, high blood pressure, diabetes, arthritis-related disabilities, and cancer.6
Obesity affects every system in the body. In the pulmonary system it can cause obstructive sleep apnea and hypoventilation syndrome. Obesity can cause nonalcoholic fatty liver disease (steatosis, steatohepatitis and cirrhosis), and has been linked to increased incidence of cancer of the colon, the esophagus and the pancreas. Obesity increases the likelihood of developing severe pancreatitis and gallbladder disease. For women it contributes to the development of abnormal menses, infertility, and cancers of breast, uterus, and cervix. Obesity is also linked to higher rates of osteoarthritis, gout, and phlebitis.6
Economic Impact
The estimated total cost of obesity in the United States in 2000 was about $117 billion.1 Since then, these costs have been escalating dramatically. According to the 1998 Medical Expenditure Panel Survey (MEPS) and the 1996 and 1997 National Health Interview Surveys (NHIS), the total U.S medical expense for managing obesity was $78.5 billion accounting for 9.1 percent of total health expenditures. The Current Total Estimation is $122.9 billion. The Behavioral Risk Factor Surveillance System (BRFSS) used these surveys to estimate the cost each state spends medically on obesity. The majority of the expense is for the care of diabetic patients.7
Treatment and Management
Promoting regular physical activity and healthy eating, and creating an environment that supports these behaviors, are essential to addressing the obesity epidemic.
Patient education should be prioritized in the initial treatment approach, and should include management for sustained weight loss, intensive counseling, and behavior modification. Patients may not agree to participate in all the available options, but they should be made aware of what is available to them. The U.S. Preventive Service Task Force recommends screening by checking BMI, waist circumference, and evaluating for risk factors. This can be performed on every patient at every visit. It is important to educate patients on proper weight loss, which ideally should be about 1 pound per week in the first month and about 5 percent below baseline by 3-6 months.8 Men who are of similar weight and height to women will lose more weight comparatively, and older people will lose weight more slowly. Complete management includes behavior modification, diet modification, and exercise. In 2000, the Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults suggested treatment based on patient BMI and co-morbidities. (Table 4)
1. The Critical Role of Nutrition
Eating the correct foods for weight loss is critical. The food pyramid can serve as the cornerstone of a balanced diet. Today there are several meal modifications that have shown to cause weight loss. How to utilize low fat diets in approaching weight loss is controversial, as studies in countries where the fat intake has been stable still demonstrate an increasing prevalence of obesity. It is however, well documented that high fat diets have been linked to heart disease and cancer.11 In people trying to lose weight, total fat consumption should be limited to less than 30 percent of daily calories, with saturated fats comprising less than 7 percent and trans fats comprising less than 1 percent. Polyunsaturated and monounsaturated fat should be used instead. Low carbohydrate diets cause short term weight loss in about two weeks.11 This is due to fluid loss, as low carbohydrate intake eventually causes ketosis, which in turn leads to sodium loss, and finally fluids loss. The low carbohydrate approach should not be used long term for weight loss and healthy proteins and fats should be consumed with this diet.9
Use of high fiber diets, characteristic of countries outside the United States, seems to correlate with maintenance of desired lower weight.11 This is likely due to the gylcemic index. Foods with low glycemic index tend to be high in fiber. Large consumptions of alcoholic beverages, sugar-containing beverages, and high-concentrated sweets should be avoided as they have little nutritional value.
In choosing a low-calorie diet, daily caloric intake and the exact foods to meet these needs must be planned. Foods should contain enough protein, carbohydrates, and fiber to meet daily requirements. Convenient low-calorie meal plans can be prepackaged as meals or drinks. Meal substitution of one meal per day with packaged meals and possibly additional vegetables, have shown to cause early initial weight loss, which was also able to be maintained. A one-year randomized trial compared four diets11: Atkins, a very low-carbohydrate diet; Zone, a macronutrient balance controlling glycemic load diet; Weight Watchers, a calorie restricted diet; and Ornish, a very low fat diet (Table 3). All diets showed an approximate weight loss of 4-7kg without significant difference. The major predicting factor for the diet was compliance, rather than which diet was followed. Improved cardiovascular risk factors were dependent on the actual weight loss, and not the diet itself.9
Monitoring nutritional status is essential. Good nutrition begins in infancy. Children who were not breastfed are at increased risk for obesity, asthma, and some childhood infections. Of concern for both children and adults, particularly in underdeveloped countries, is micronutrient malnutrition, which can negatively affect survival and growth for children, health and pregnancy outcomes for women, and resistance to illness for both.
2. Behavior Modification
Help patients make long-term changes to modify food intake, modify physical activity, and control environmental stimuli. Some patients may have to change routines they have practiced for many years. Patients should have an active role in weight loss including self-monitoring with food journals and exercise journals. They should bring these journals to the office visit, and discuss their progress with the physician, nutritionist, or counselor. This will encourage patients to make modifications in behaviors early in treatment, which could last a lifetime. Patients should control stimuli or triggers that cause them to overeat or choose foods with poor nutritional value. Slowing down the eating process has been shown to cause satiety by allowing the brain time to receive the appropriate messaging. Social Support with anonymous groups can be an effective outlet for the patient.10
3. Physical Activity: How Much is Enough?
Physical activity is defined as any activity that involves one or more large muscle groups and increases heart rate. To improve health related outcomes 30 minutes of moderate activity most days of the week (150 minutes/week) is recommended by the CDC, American College of Sports Medicine, and Surgeon General.13
For maximize weight loss and preventing weight regain, 45-60 minutes/day is recommended by the Institutes of Medicine, 60-90 minutes/day is recommended by the International Association for the Study of Obesity, and 60 minutes/day (300 minutes/week) is recommended by the American College Sports Medicine.11
Exercise has been shown to improve glycemic control and insulin sensitivity and may prevent the development of type 2 diabetes.14 It decreases the risk of CAD, decreases abdominal obesity, and decreases systemic blood pressure. Exercise alone, without diet modification, causes very little weight loss. Exercise has been shown to decrease the risk of obesity regardless of genetic disposition. In a study using twin females in which one was overweight, regular exercise demonstrated a decrease in total body fat and abdominal fat, and was a major factor in body weight maintenance after weight reduction.12
Exercise programs should be tailored for the individual, accounting for body type, age, existing medical conditions, and exercise preference. The 2002 ACC/AHA guidelines recommend screening prior to beginning an exercise program for asymptomatic diabetics who plan on doing vigorous exercise.14
Estimated energy expenditure based on lifestyle can be calculated, which gives the patient a better estimate of their suggested caloric intake (Table 6).
Regular physical activity reduces risk and provides therapeutic benefits for people with heart disease, colon cancer, diabetes, and high blood pressure and may reduce their risk for stroke. Regular physical activity also helps to control weight, contributes to healthy bones, muscles, and joints, reduces falls among older adults, helps to relieve the pain of arthritis, reduces symptoms of anxiety and depression, and is associated with fewer hospitalizations, physician visits, and less medication use. Moreover, physical activity need not be strenuous to be beneficial. For example, adults of all ages benefit from moderate-intensity physical activity, such as 30 minutes of brisk walking most days of the week.12
Despite the proven benefits of physical activity, more than 50 percent of U.S. adults do not get enough physical activity to provide health benefits, and 25 percent are not active at all in their leisure time.1
Activity decreases with age, and sufficient activity is less common among women than men, and among those with lower incomes and less education. Approximately two-thirds of young people in grades 9–12 are not engaged in the recommended levels of physical activity. Daily participation in high school physical education classes dropped from 42 percent in 1991 to 33 percent in 2005.1
Evidence-based guidelines for physical activity for youth, adults, and older adults are being developed at the national level. Partners engaged with this project include CDC, the President’s Council on Physical Fitness and Sports, and the U.S. Department of Health and Human Services’ Office of Disease Prevention and Health Promotion. CDC is leading the literature review, which will provide the scientific basis for the development of these guidelines.1
4. Pharmacotherapy
Pharmacotherapy has become an important component of management in the overweight and obese patient. Medication should be considered for patients who fail to lose weight with lifestyle modification, have a BMI 25-29 with increased waist circumference, or a BMI 27-30 with risk factors. There are several medications available for weight reduction, however only two have been approved for long-term use by the FDA for the management of obesity.6 Patients should be aware that weight is usually regained after termination of medication and that there is not a cure for obesity.
Sibutramine (Meridia) inhibits norepinephrine and serotonin and causes decreased food intake. It has shown dose-related weight loss for 6 months with weight maintenance demonstrated over two years.6 The weight loss produces benefits in the patient’s lipid profile, body composition, and is associated with a decrease in mean blood pressure. Trials in diabetics showed an improvement in body weight and hemoglobin A1c, a decrease in triglycerides and an increase in HDL.6
Patients on sibutramine should have their blood pressure monitored regularly, especially during the first four weeks of therapy, when sibutramine may have central sympathetic effects on blood pressure. An unacceptable rise in blood pressure occurs in less then 5 percent of patients. The dose of sibutramine should be decreased if this increase in blood pressure is noted. These effects can be counteracted by beta blockers and a regular exercise program. Physicians should prescribe a sensible diet similar to meal replacements for two meals and two snacks, plus one sensible meal per day, or a portion controlled diet with at least three meals per day.6
Orlistat (Xenical & Alli) demonstrated weight loss in the first six months and maintenance over four years.6 Weight loss was associated with benefits in glycemic control, lipids, waist circumference, and blood pressure.6 Orlistast has also shown independent action on lowering LDL cholesterol. Patients choosing orlistat should be advised of potential bowel effects, especially with high fat meals, and be given vitamin supplementation if using the medication long term. Metamucil can help decrease the untoward bowel effects.6
Other pharmacotherapy has been approved for short-term use in weight loss. Sympathomimetics such as phentermine decrease food intake by causing early satiety. The medication is rapidly absorbed and peaks in one to two hours. Patients should be warned of abuse potential and forewarned of short duration utilization.
Some medications have special use in specific patient populations. Bupropion (Wellbutrin) and venlafaxine (Effexor) can be used in the depressed, obese patient. Wellbutrin has demonstrated weight reduction in a six month trial verses placebo. In type two diabetics, metformin, pramlintide (Symlin), and exendin-4 (Exenatide) have been shown to cause weight loss.6
None of these medications proved significant weight loss (over 5 percent of body weight), although even a small amount of weight loss in the diabetic patient is beneficial. Trials have shown a 2.5 percent weight reduction with metformin, 0.4kg reduction with Pramlintide, and 4.5kg reduction with Exenatide. Epileptic drugs topiramate (Topamax) and zonisamide (Zonegran) have also shown weight reduction. Neither drug, however, is currently recommended as weight reduction therapy.13
Rimonabant (Acomplia) is a cannabanoid receptor antagonist that has been approved in Europe for weight reduction. The FDA is currently investigating the risk of seizures and suicide with this medication.6
5. Surgery
Bariatric Surgery is a recommendation for patients between ages 18 and 50 years old, with a stable preoperative weight for 3-5 years, and smoking cessation for at least 6 weeks. NIH recommends surgery for patients with BMI ≥ 40 or BMI ≥ 35 with co-morbid conditions. The operation dramatically restricts gastric size, therefore reducing nutritional intake. Some side effects and complications are iron deficiency, vitamin B12 deficiency, folic acid deficiency, dehydration, vitamin A deficiency, electrolyte deficiency, and protein deficiency.14
Government Support and interventions
The Centers for Disease Control and Prevention are committed to ensuring that all people, especially those at greater risk for health disparities, will achieve their optimal lifespan with the best possible quality of health in every stage of life.15 Specific goals are established to support healthy behaviors in the population and to provide healthy places to all Americans.
To achieve these goals, the Division of Nutrition, Physical Activity and Obesity (DNPAO) was created. DNPAO has the mission of leading strategic public health efforts to prevent and control obesity, chronic disease, and other health conditions through regular physical activity and good nutrition. The Division’s goals focus on increasing health-related physical activity through population-based approaches, improving aspects of dietary quality most related to population burden of chronic disease and unhealthy child development, and decreasing the prevalence of obesity through prevention of excess weight gain and maintenance of healthy weight loss.
In 2007, the Nutrition and Physical Activity Program to Prevent Obesity and Other Chronic Diseases (NPAO) funded obesity prevention and control activities in 28 states.16 New funding announcements are due for the next fiscal year. Funded states will address increasing physical activity, breastfeeding, consumption of fruits and vegetables, decreasing consumption of sugar-sweetened beverages, high energy-dense foods, and limiting television viewing. State efforts will include making policy and environmental changes to encourage access to healthy foods and places to be active, strengthening obesity prevention, and controlling programs in preschools, child care centers, work sites, and other community settings.
Evaluating interventions to determine effectiveness is an important part of the process. Physicians should become more engaged in the process of identifying outcomes and determining future efforts. It is essential for the osteopathic family physician to be cognizant of this growing knowledge base, and to appreciate how to utilize these readily available resources.
Progress in Obesity Research
Obesity has been recognized as a national public health concern. National and international efforts have focused on increasing recognition of this epidemic. During 2000–2006, the number of articles on obesity published in the national press increased from 2,000 to 6,000 (International Food Information Council).20
At the national level, CDC is involved in the creation, evaluation, and modification of programs, policies, and practices to prevent and control obesity. The CDC has created the infrastructure to promote physical activity and good nutrition in multiple settings. An integral part of this campaign is teaching communities innovative strategies to promote physical activity and good nutrition.
An essential aspect of the management of obesity is the integration of knowledge and interventions into daily clinical practice. Emerging strategies in the study of nutrition and physical activity are of great importance in confronting obesity. Occupational medicine specialists should contribute to the management of this epidemic by identifying strategies to prevent and control obesity among their employees at their site of employment.
Obesity should be viewed as an emerging pandemic. National and international agencies, both governmental and private, must unite forces to battle this disease process. CDC’s World Health Organization Collaborating Center for Physical Activity and Health Promotion is well positioned to provide global and regional leadership in developing evidence-based research protocols and public health practice guidelines related to physical activity and health as interventions in the management of obesity.
Concluding Remarks
Obesity has strong and complex associations with gender, age, ethnicity, and socioeconomic status.21 Population-centered approaches are needed to target this epidemic, and it cannot be accomplished at the physician’s office alone. The development of partnerships between physicians, patients, health delivery systems, insurers, and governmental and non-governmental agencies is paramount for the successful implementation of effective strategies.
Physicians should become more integrated in communities where a higher incidence of obesity is seen, particularly in low-income and minority areas. Children living in lower-income households typically have easier access to fast-food restaurants and fewer vendors of healthful foods, than do those in more affluent neighborhoods. The safety of communities is of extreme importance, as many obstacles to physical activity originate from unsafe streets, abandoned parks, and lack of healthy city infrastructures.
Physicians have a great opportunity to influence the health of children attending schools in neighborhoods in lower socio-economic locales. In addition, family physicians should be aware of the condition of the home environment, disposition to breast-feeding, television over-viewing, and parental behaviors which may contribute to childhood obesity. Developing systematic interventions that target these behaviors may greatly reduce the obesity rate in these vulnerable populations.17
Dr. Newman is a 2005 graduate of the Nova Southeastern University College of Osteopathic Medicine (NSUCOM). She completed a Family Practice Residency at the NSU/Broward General Medical Center in 2008. She is currently a Fellow in Palliative Medicine. Dr. Calzada is a 1993 graduate of NSUCOM. He serves as Assistant Dean of Clinical Operations and Associate Professor of Family Medicine and Public Health at NSUCOM.
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