Management of Obesity
Authors: John P. Foreyt, PhD, Professor, Department of Medicine, Baylor College of Medicine, Houston, Texas; and Victor R. Pendleton, PhD, Primary Care Postdoctorate Fellow, Department of Medicine, Baylor College of Medicine, Houston, Texas.
Peer Reviewers: Judith Ashley, PhD, RD, Associate Director, The Nutrition Education and Research Program, University of Nevada School of Medicine; and Walker S. Carlos Poston, MPH, PhD, Assistant Professor, University of Missouri—Kansas City, Mid America Heart Institute.
Editor’s Note—We are witnessing an epidemic of overweight and obesity in our society. More than half the adult population of the United States is affected. This increase in prevalence is having a deleterious effect on the health of our population. Overweight and obesity are strongly associated with morbidity and mortality. Although genetic predisposition may play a minor role in the increasing prevalence, the environmental factors that affect food intake, eating behavior, and physical activity are the primary determinants. There is a strong need for a structured approach to obesity management. The basic principles include a comprehensive clinical assessment, achievable weight loss goals, and realistic lifestyle changes in dietary behavior and activity levels. Imparting the lifestyle strategies for achieving long-term eating and physical activity habits is essential for successful management. Self-monitoring is the most critical one for maximizing chances of success. Many primary care physicians (PCPs) are reluctant to prescribe drugs to treat obesity even though there are efficacious agents available to help patients manage their diet. Antiobesity drugs can serve as important adjuncts for patients who struggle with dietary change. Surgical approaches can also be effective treatments for obesity and help some severely obese patients achieve medically significant sustained weight losses. The recognition that obesity is a chronic disease for which there is no cure has increased concerns about future generations. More effective methods of prevention are needed if we are ever to stem this major public health problem.
Obesity is among the most pervasive public health problems in the United States.1 It is a deceptively complex, multifactorial chronic disease of appetite regulation and energy metabolism involving the integration of metabolic, physiological, biochemical, genetic, behavioral, social, and cultural factors.2,3 While our understanding of how obesity develops is incomplete, there is agreement about the health risks of being obese. Obesity is associated with increased morbidity and mortality. It is related to type 2 diabetes, hypertension, dyslipidemia, coronary heart disease, stroke, gallbladder disease, osteoarthritis, sleep apnea, respiratory problems, and some cancers.4-6
Obesity is seen by many in the general public as the result of gluttony and sloth. It would disappear if only obese individuals would "eat less and exercise more." Unfortunately, obesity is a striking disease with respect to the amount of effort needed and the vigilance required for its management.7 Published studies suggest that although individuals who complete weight loss programs lose about 10% of their weight, virtually all of them gain it back within five years.
The purpose of this article is to briefly review for the PCP what is known about the disease of obesity and to describe currently used strategies for its management.
Obesity is an excess of body fat. It has been defined as the point at which health risks are believed to accelerate. This point is defined as more than 25% body fat in men and more than 33% in women.8 Assessment strategies for estimating body fat include hydrodensitometry (underwater weighing), air displacement plethysmography, dual x-ray absorptiometry (DXA), isotope dilution, total body potassium, skinfold measurements, bioelectrical impedance, ultrasound, total body conductivity (TOBEC), computed tomography (CT), magnetic resonance imaging (MRI), and neutron activation.
In hydrodensitometry, the person is weighed using a specialized scale while completely submerged under water. The principle behind the technique is that fat floats and nonfat components sink. This technique was the gold standard until the advent of DXA. The DXA method requires the person to lie on a table while low-energy x-rays are beamed through the body. Estimates of lean body mass, body fat, and bone content are possible. The cost of the DXA equipment ranges from $40,000-$100,000. People weighing in excess of 300 lbs may not be testable because of the structural limitations of the equipment. The skinfold technique involves the measurement of subcutaneous fat at predefined points on the body using a special pincher-type device known as a skin caliper.
The skinfold technique is a common method of estimating body fat because it involves the use of inexpensive equipment and is easy to administer. The technique may be less reliable than previously mentioned methods because of variation in measurement instrumentation and problems with inter-rater reliability. Because the jaws of the caliper open only so far, extremely large fat deposits may preclude the use of this technique. In bioelectrical impedance, a weak electric current is passed through the body. The principle behind this technique is that current flow is facilitated through hydrated, fatfree tissue and is impeded by dense adipose tissue. Therefore, the more body fat, the higher the impedance. Though this technique is modern in its use of technology, it may be less accurate than previously mentioned methods due to its sensitivity to the person’s level of hydration. For example, women who are menstruating or individuals who have recently consumed alcoholic beverages may produce inaccurate results.
Body fat can be estimated using a portable ultrasound meter. This device measures subcutaneous fat using sound reflectance. This technique has good reliability and does not limit the size of the person to be evaluated. TOBEC is a technique that relies on the changes in electromagnetic characteristics as a function of fat and water. Like the DXA, the equipment is expensive but may be useful in specialized research settings.
Though accurate, the imaging techniques, CT and MRI, are also expensive. In a clinical setting for the treatment of obesity, the cost/benefit ratio of this high-end equipment may be prohibitive. Less expensive techniques, such as skinfold measurement and ultrasound, performed according to established protocols, can produce results with 95-97% accuracy.9 This level of accuracy is probably enough for the PCP. However, even these techniques require time and equipment.
In order to reduce the time and effort necessary to capture a useful measure of body composition, quicker ways are used to define obesity. Body mass index (BMI), expressed as weight in kilograms divided by height in meters squared (kg/m2), has emerged as the favored measure among researchers and is increasingly being used clinically by PCPs. The BMI is significantly correlated with total body fat. (See Table 1.) The cutoffs defining adult underweight, normal weight, and obesity in terms of BMI are given in Table 2. The advantages of using the BMI for PCPs are its ease of use and its accuracy in measuring both weight and height. It allows the same criteria to be applied independent of gender. It is a good estimation of excess body fat in BMIs greater than 25, and works especially well in BMIs greater than 30. The BMI does not work well with highly muscled athletes who have abnormally high levels of lean muscle mass. At this time, the BMI categories are restricted to men and women who are past puberty. Categorizing growing children by BMI could result in erroneous estimates of body composition.9 BMI categories for use with children are not presently available. The BMI also can be determined using inches and pounds: (weight in pounds divided by height in inches squared × 703 [i.e., lbs/in2 × 703]).
Currently, 55% of the adult U.S. population is overweight or obese.1,6 As indicated in Table 2, the definition of overweight is a BMI of 25 or greater, and obesity is a BMI of 30 or greater. A total of 32.6% of the adult population is overweight and 22.3% is obese. Table 3 illustrates the rise in the percentage of the U.S. population from 1960-19946 that is obese. The highest prevalence of obesity is in the minority population, with 36.5% of black women and 33.3% of Mexican-American women having BMIs greater than 30. The lowest prevalences of obesity are white men (20.0%) and black men (20.6%). Obesity increases with age through age 59 then declines. Men in their 50s have an obesity prevalence of 28.9%; women, 35.6%.
|Table 2. Adult Obesity Classification Using BMI||BMI|
|Severe Obesity||> 40|
|Table 3. Obesity Trends (%) in the United States (BMI > 30; ages 20-80+)6|
|Men (%)||Women (%)|
The prevalence of childhood obesity is also increasing, with estimates ranging from 20-30%.10,11Childhood obesity predicts adult obesity. One-third of all obese adults were obese as children.12The Bogalusa heart study suggests that there has been a 50% increase in obesity of 6- to 11-year-olds since 1973 and that the trend is continuing.13Another study reported an 80% increase in the incidence of obese children becoming obese adults.14Adults with the onset of obesity in childhood have more severe obesity and earlier onset of comorbidities. The likelihood of an obese child becoming an obese adult increases as children age and remain obese.
Etiology and Pathogenesis
The epidemic of obesity that we are currently experiencing is the result of an imbalance between energy expenditure and caloric intake. The causes of this imbalance are related to genetic predisposition and changes in the human environment and lifestyle.15,16 The ability to store fat during periods of ample food availability is an environmentally selected trait that increases the individual’s chances of survival during periods of famine.16,17 Researchers have theorized that the human genome is characterized by susceptibilities that interact with environmental factors to produce obese phenotypes.17 Ironically, the major environmental factors that interact to produce the harmful and ever-increasing levels of adiposity in modern society are the high availability of calorie-dense foods and the absence of a physically demanding environment.18-20
Assessment is useful in the design and optimization of treatment approaches. Assessment helps the provider target specific problem areas for change. Typical areas of assessment are degree of obesity, diet/eating patterns, physical activity patterns, emotional state, and readiness to change. Degree of obesity can be useful in selecting the most appropriate treatment modality. For example, cognitive-behavioral strategies have been used most often with individuals who are overweight to moderately obese (BMI from 25-40).6 Other approaches, such as surgery, may be indicated for patients with severe obesity (BMI > 40).6
Dietary Assessment. Considering the major role of diet in the pathogenesis of obesity, evaluation of dietary patterns is often an important component of treatment planning. On the other hand, the labor-intensive nature of traditional assessment methods, such as 24-hour recall and food-frequency questionnaires, challenges the primary care provider’s ability to deliver quality service in a time-efficient manner. In response to this dilemma, brief dietary assessment questionnaires have been developed. Some of these questionnaires are targeted to the dietary management of specific medical conditions. Examples of such instruments are the MEDFICTS Dietary Assessment Questionnaire21 and the Rate Your Plate22 dietary assessment questionnaire, which target management of cholesterol, and the Eating Pattern Assessment Tool,23 which is aimed at patients interested in maintaining a heart-healthy diet. These tools assess the frequency at which certain food groups are eaten per week, as well as typical serving sizes. These results, though targeted for the management of specific medical conditions, are generalizable to obesity management because they provide a description of the patient’s daily eating patterns. One advantage of these brief assessment tools is that the primary care provider is able to capture reliable data about the general eating patterns of the patient with a minimum of time expended. Another advantage is that the patient gains self-awareness of eating behavior. Many of these instruments are self-scored and guide the patient through a process of goal setting to achieve a healthier diet. If more detailed records of eating behavior are desired, it is best acquired with the assistance of, or referral to, a registered dietitian.
Physical Activity Assessment. The issues related to the assessment of physical activity are similar to those of eating behavior. Treatment planning can be enhanced by knowledge of physical activity patterns but the cost in time of traditional assessment methods is often prohibitive. General patterns of physical activity may be efficiently determined using the Self-Administered 7-Day Physical Activity Recall Questionnaire.24 This simple, two-question instrument provides a means of capturing general information regarding the patient’s level of moderate to vigorous physical activity during the most recent seven-day period. Although this instrument does not provide detailed information at the kcal level, it may provide enough data to guide the provider in treatment planning and recommendations.
Emotional Assessment. A 24% prevalence of depression was reported in a recent study of outpatients in a primary care setting.25 The prevalence among obese patients who also binge eat is high.26 Assessment of emotional status is important in the treatment of obesity.27 Many patients suffering from depression will have difficulty adhering to a weight management program. Depressed patients may ultimately experience more success if the depression is treated before a weight loss program is begun.28,29 A number of well-documented instruments helpful in identifying depression are available, including the Beck Depression Inventory for Primary Care (BDI-PC) and the Center for Epidemiologic Studies Depression Scale (CES-D).30 The BDI-PC is a self-administered seven-item questionnaire that reliably identifies depression in a primary care setting.25 The CES-D is a 20-item self-administered scale that has good psychometric properties, is brief, easy to use, and is a public document.
Stage of Change Assessment. Obese patients will present at different levels of readiness to change. Understanding where the patient is in this regard may help the therapeutic process by guiding the selection of treatments that are congruent with the patient’s desire to change. The Stages of Change model was proposed to facilitate this process.31 It categorizes people with problem conditions into one of five stages: precontemplation, contemplation, preparation, action, and maintenance. Precontemplators may not be at all concerned with their condition. Contemplators may be concerned but not yet decided on taking action. If the patient is not ready to begin a weight management program, suggestions to take action will probably fall on deaf ears. A different approach, involving education and personalization of risk factors, may be the most appropriate intervention for these individuals. Patients in the preparation stage may have decided to do something about their condition but have not yet begun. Such patients may need encouragement to take action and to make a commitment to their health and well-being. Patients who are ready to take action, or who have recently begun taking action, would benefit most from behavioral interventions such as goal setting and self-monitoring. They may use information describing community resources and group activities available to help them meet their goals. People in the maintenance stage would benefit from moral support and recognition of the good things they are doing for themselves. Table 4 describes some diagnostic questions that are useful in determining the patient’s current stage of change.
|Table 4. Sample Questions for Determining Exercise Behavior Stage of Change|
|Which statement most accurately describes you?|
|Precontemplation—I do not exercise and have no plans to start.|
|Contemplation—I plan to begin exercising in the next six months.|
|Preparation—I plan to begin exercising in the next month.|
|Action—I have begun exercising on a consistent basis during the past six months.*|
|Maintenance—I have been exercising on a consistent basis for more than six months.|
|* Consistent exercise = 3 or more times per week for 20 minutes or more.|
Lifestyle Change Strategies
In the management of obesity, the primary focus should be to increase physical activity, normalize caloric consumption, and create realistic expectations of success. There are seven basic lifestyle change strategies to help patients make the necessary adjustments in eating and physical activity to lose and maintain body weight.
Set Realistic Goals. Goals for losing weight frequently differ between patient and physician. Unrealistic goals need to be addressed early. The average weight a patient will lose in a treatment program is about 8-10%;6 many patients want to lose much more than that. One strategy is to help the patient set moderate short-term goals and focus on the health benefits of even modest amounts of weight loss. The patient is encouraged to re-evaluate periodically and to reset goals if necessary. This method has the dual benefit of providing the patient with feelings of success for having met short-term goals, while approaching the long-term goal at a moderate pace that is conducive to long-term maintenance. Patients may benefit from being reminded that setting unrealistic goals is setting oneself up for failure.
Self-Monitoring. The most important lifestyle change strategy is self-monitoring. Self-monitoring involves the observation and recording of specific personal behaviors, related feelings, and environmental cues.32 For the patient working to manage obesity, the purpose of self-monitoring is to raise the awareness of eating and physical activity behavior and the factors contributing to it. The patient is asked to record foods eaten and aspects of the environmental situation in which the eating occurred. Feedback—in the form of calories, food groups, or fat grams—can help the patient see what changes need to be made. Also, consistent recording symbolizes compliance, which may be reinforcing in and of itself.
Although it is desirable for patients to be accurate in the records they keep, absolute accuracy is not necessary. Less accurate recording may still lead to improvement because of the patient’s increased awareness of diet and activity patterns, and the factors that influence them.33,34 Self-awareness enables the patient to target areas for change that will have the greatest effect. Studies have shown self-monitoring to be consistently related to improved treatment outcomes, and patients report that it is one of their most helpful tools.
We find that physicians often do not like to ask their patients to keep food diaries, and patients do not like to fill them out. Yet, diaries are the single most useful tool for raising patients’ awareness of their eating and physical activity patterns. The food diary is the most helpful behavioral strategy we have. Encourage patients to keep one.
Stimulus Control. Stimulus control involves the identification and modification of the environmental factors contributing to overeating or underexercising.33 After environmental factors to overeating and/or sedentary behavior have been identified using a diary, stimulus control techniques may be used to weaken or eliminate the influence of the cues. For example, if food availability is found to be a cue for overeating, then eliminating tempting foods from the house might result in reduced caloric consumption. Another example is when patients identify a lack of motivation as the reason for missing scheduled exercise sessions. In such cases, telephone reminders or participation in an exercise group may be useful in motivating patients to stay on track. Laying out exercise clothes and walking shoes before going to bed may make it easier for patients to exercise when waking up the next morning.
Cognitive Restructuring. Cognitive restructuring involves changing inaccurate beliefs.35 This procedure encourages patients to examine their inner dialogues (i.e., their thoughts and feelings about themselves and their obesity). It challenges them to change those who are determined to be inaccurate or counterproductive. For example, some patients believe that losing weight will result in happiness in many other aspects of their lives. If such patients lose weight but do not achieve happiness in the other areas, they may become discouraged and return to old behavior patterns. Patients who have endured a lifetime of obesity may have problems seeing themselves as new leaner persons. Failure or relapse may be expected because of these distorted self-images. The purpose of cognitive restructuring is to identify self-defeating cognitions and to help patients replace them with more productive ones. Having patients write down and repeat positive self-affirmations, such as "I will walk at least 30 minutes today," can often serve as helpful reminders for behavior change.
Stress Management and Inoculation Training. Stress is a strong predictor of overeating and relapse.36 Therefore, it is not surprising that stress management and inoculation training are useful in the management of obesity because they teach the patient techniques for identifying, handling, and reducing stress. Some of these techniques include diaphragmatic breathing, progressive muscle relaxation, and meditation. Inoculation seeks to develop in the patient the ability to resist environmental stimuli that might ordinarily lead to relapse. Inoculation is done by exposing the patient to the stimulus and practicing successful negotiation of it.37 Exposure may be done in vivo or through guided imagery. For example, the stimulus may be the offer of a piece of cake at a birthday party or the feelings of anger toward a coworker. Successful negotiation may be practiced by selecting from options such as walking away, declining the offer, or taking a time-out to reduce the state of arousal.
Relapse Prevention Training. Relapse prevention training normalizes relapse as part of the weight-loss process.33,37 It teaches patients to accept relapse as a possible eventuality and prepares them to manage the relapse by minimizing the damage and getting back on track as soon as possible. By anticipating relapse and having coping strategies in place, a full relapse may be avoided.
Social Support. Studies consistently show the value of support systems in improving compliance with obesity management programs.33,38,39 Incorporating social support consists of including others in the patient’s management program. This may be done by encouraging the participation of family members and friends, or by referring the patient to a group of like-minded people with similar goals. Social support may also be achieved by encouraging the patient to seek out group exercise and recreation programs. Social support facilitates the obesity management process and benefits the patient by providing positive social influence to adopt new behaviors, by developing self-acceptance, and by providing an outlet for the frustrations often experienced by obese people trying to make lifestyle changes.
According to the recommendations of the NIH/NHLBI clinical guidelines, drugs may be a useful adjunct to modifications in behavior, including diet and physical activity. The recommendation of the guidelines is that "weight loss drugs may only be used as part of a comprehensive weight loss program including diet and physical activity for patients with a BMI of 30 or greater with no concomitant obesity-related risk factors or diseases, or for patients with a BMI of 27 or greater with concomitant obesity-related risk factors or disease."6,40 Currently, there are two drugs for obesity that are approved by the Food and Drug Administration (FDA) for long-term use: sibutramine (Meridia) and orlistat (Xenical).
Sibutramine. Sibutramine was initially developed as an antidepressant. Weight loss was noticed in depressed patients who took the drug who were not actively attempting to lose weight. Sibutramine is a serotonin and noradreneline reuptake inhibitor.41 It has been studied in randomized, double-blind, placebo-controlled trials lasting 6-12 months. More than 20 trials involving obese subjects have been reported. Subjects have included those with uncomplicated obesity and those with dyslipidemia and type 2 diabetes. Dose-response relationships were observed. Weight losses were significantly greater in the sibutramine-treated subjects than in those receiving placebo. Sibutramine-treated subjects typically lost about 6-10% of body weight over 6-12 months.
Adverse events are predictable based on its pharmacology. There is a mean increase in blood pressure of 1-2 mm Hg and a mean increase in heart rate of four beats per minute. In some patients, sibutramine may substantially increase blood pressure. Potentially clinically significant increases in blood pressure have been reported with an incidence of 2% relative to placebo in uncomplicated obesity. Sibutramine should be used with caution in patients with a history of hypertension and should not be given to patients with uncontrolled or poorly controlled hypertension. The physician should monitor blood pressure in all patients.
There has been no reported increase in ischemic coronary events, arrhythmias, or cerebrovascular events with use of sibutramine. There have been no cases of primary pulmonary hypertension attributable to sibutramine reported and no increase in valvular heart disease compared with placebo subjects. No neurotoxicity has been seen. Drug interactions include monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), erythromycin, and ketoconazole.
Orlistat. Orlistat is a lipase inhibitor that works by reducing the body’s absorption of dietary fat.42,43 It is a nonsystemic drug that blocks 30% of dietary fat. It works in the gastrointestinal tract. To date, there have been seven one- and two-year randomized, double-blind, placebo-controlled trials involving more than 4000 patients. In all studies, patients who took orlistat lost significantly more weight than those receiving a placebo. Almost three times as many patients taking orlistat achieved weight loss of more than 10% compared to placebo. Twice as many lost at least 5%. Orlistat-treated patients showed improvements in total and low-density lipoprotein (LDL) cholesterol, blood pressure, and fasting insulin and glucose.
Orlistat is contraindicated in patients with chronic malabsorption syndrome or cholestasis, and in patients taking cyclosporine or with a known sensitivity to any component of orlistat. Orlistat treatment effects include changes in bowel habits such as oily or loose stools, the need to have a bowel movement quickly, bloating, or oily spotting. They tend to occur when patients consume more than 30% of calories from fat. These effects may be minimized once the patient lowers the fat in the diet to less than 30%. Because orlistat blocks dietary fat, it reduces absorption of fat-soluble vitamins A, D, E, and K, and beta carotine. Patients on orlistat require a multivitamin supplement containing fat-soluble vitamins.
The NIH/NHLBI clinical guidelines recommend that "surgical intervention is an option for carefully selected patients with clinically severe obesity (a BMI of ³ 40 or ³ 35 with comorbid conditions) when less intensive methods of weight loss have failed and the patient is at high risk for obesity-associated morbidity and mortality."6
Severely obese patients are often not helped by more conservative weight loss approaches, including lifestyle change strategies. The NIH consensus conference on surgical approaches for weight loss concluded that this aggressive approach is reasonable for severely obese persons who are at increased risk for premature death and that the potential benefits are greater than the risks.44 Weight losses following surgery may be as much as 100 lbs or more over 12 months. The ongoing Swedish Obesity Study (SOS) reported that gastric bypass resulted in greater weight losses than gastroplasty at 12 months (93 lbs vs 67 lbs, respectively).45 Comorbidities also show significant improvements following surgery.
There are numerous randomized controlled trials that demonstrate the efficacy of adhering to a balanced, reduced calorie diet.6,46 Reduced calorie diets based on USDA guidelines, which create a deficit of 500-1000 calories per day, are indicated for any program aimed at achieving weight loss of 1-2 pounds per week.6 The USDA guidelines describe food choices that promote good health. These are presented in the form of recommended numbers of servings from the five major food groups (see Figure 1).
Reduced Caloric Consumption. The USDA standard serving for meat is 3 oz. Serving sizes in restaurants today frequently exceed 8 oz. The standard serving size for popped popcorn is 3 cups. At the movies, 16-cup servings are common. In fast-food lines, the offer of "super-sizing" is standard. These trends make reduced caloric consumption difficult. Many patients do not understand standard portion sizes. Descriptions of typical serving sizes are useful in helping patients conceptualize the amount of food that makes up a recommended serving. The USDA provides useful pamphlets to assist in patient education.47
Normalized eating refers to eating in accordance with a person’s daily caloric requirements. Daily caloric requirements represent the intake necessary to maintain current body weight. Patients need to know their requirements. Daily caloric requirements can be estimated using the following age- and gender-specific formulas48:
18-30 y: RMR = 15.4 × weight (kg)-27 × height (m) + 717 30-60 y: RMR = 11.3 × weight (kg) + 16 × height (m) + 901
> 60 y: RMR = 8.8 × weight (kg) + 1128 × height (m)-1071
18-30 y: RMR = 13.3 × weight (kg) + 334 × height (m)-35
30-60 y: RMR = 8.7 × weight (kg-25 × height (m) + 865
> 60 y: RMR = 9.2 × weight (kg) + 637 × height (m)-302
Estimates of daily caloric requirements can be calculated by multiplying the RMR by an activity factor of 1.3 for women and men. This factor assumes a predominantly sedentary lifestyle, which is common for obese patients. For example, a 49-year-old man who is 6 feet tall and weighs 230 lbs:
RMR = 11.3 × 104.3 + 16 × 1.84 + 901 = 2109
Daily caloric requirement = 2109 × 1.3 = 2742
A daily deficit of 500 calories will result in a weight reduction of 1 lb per week, which is in accordance with current obesity management guidelines. The caloric content of many foods is given on the packaging. Pocket handbooks are also available that contain the energy value of unpackaged foods such as fruits and vegetables. Applying the self-monitoring techniques mentioned above, patients could use this information to select meals based on caloric content and thereby achieve better control toward maintaining their intake goals. The self-awareness produced by the self-monitoring effort keeps patients focused on intake and interested in the caloric content of the food they plan to eat.
In practice, it is not always possible to determine the caloric content of food choices. This is especially true when eating in restaurants and with friends. In such cases, self-monitoring is still helpful and should be continued, but the focus should shift from calories to portion sizes and fat content. It is helpful to conceptualize servings in three sizes: small, medium, and large. By selecting food in small portion sizes, especially foods that are high in percentage of calories from fat, patients can eat out with a minimum of deviation from their weight-loss trajectory.
The evidence is strong that balanced, reduced-calorie diets, with choices made according to the USDA guidelines, are effective in facilitating weight loss. Balance, variety, and moderation are still the secrets of a diet conducive to successful weight management.
When designing the physical activity component of an intervention, the type, frequency, intensity, and duration of the activities should be considered. Moderate aerobic activity is well suited for weight reduction. The types of activities selected should be matched to the patient’s physical and psychological attributes and limitations. For example, many obese people do not like bicycle riding because of the discomfort caused by narrow seats. Others avoid swimming because of the embarrassment they experience when their bodies are exposed. Compliance may be facilitated if patients can identify modes of physical activity that they find suitable.49,50
Physical activity should be worked into the patient’s lifestyle to ensure consistency. Accepted guidelines suggest that physical activity be performed at least five days per week.49,50 A gradual approach that builds up to this recommended level of activity will allow time for physical and psychological adaptations to occur and will lower the chance of injury. For obese patients beginning a program of increased physical activity, moderate intensity is indicated. During aerobic exercise, a simple test known as the "Talk Test" can be useful in assessing activity intensity. Patients are at the appropriate level of intensity if they are just barely breathing hard and are still able to carry on a conversation. This level also corresponds to a perceived level of exertion equal to 7, on a scale from 1 to 10. Duration of exercise should begin slowly, perhaps at about 10 minutes, and gradually increase to 30 minutes or more per day.49,50
Patients should keep in mind that the focus of physical activity is weight loss. Maximum physical exertion is not required. Moderate intensity can be as effective as higher intensity exertion in achieving caloric expenditure. For example, the number of calories expended to walk a mile in 15 minutes is roughly the same as required to walk a mile in 20 minutes. No doubt that walking at the more rapid pace burns calories at a faster rate per minute, but the slower walker will eventually make up the difference by walking for a longer time. Explaining the benefit of moderate intensity exercise in this way may lead the patient to value modest efforts and contribute to overall program adherence. General increases in physical activity should also be encouraged. Simple modifications, such as taking the stairs and parking a bit further out in the parking lot, can add up over the course of weeks and months.
Weight loss will be directly related to frequency, intensity, type, and duration of physical activity, as well as to caloric intake. Table 5 illustrates the amount of exercise necessary to burn off the calories from several different types of foods while walking at a normal pace (approximately 3 mph). Relating information in this way may help the patient put that extra piece of candy into perspective.
|Table 5. Minutes of Walking to Burn Calories in Some Foods|
|Minutes to Burn Calories Walking at Normal Pace|
|Calories||Individual Body Weight|
|123 lb||150 lbs||203 lbs|
|Beer (12 oz)||
|32 min||27 min||20 min|
|Cola beverage (12 oz)||
|32 min||27 min||20 min|
|34 min||28 min||22 min|
|Dairy Queen Reg Shake||
|1 h 33 min||1 h 17 min||56 min|
|McDonald's Big Mac||
|2 h 7 min||1 h 46 min||1 h 17 min|
Problems Frequently Encountered by Primary Care Providers
Successful management of patient obesity is not a simple process. This section discusses some of the specific problems often faced by the primary care provider working with obese patients.
Side Effects of Medications. Some medications have weight gain as a side effect. These medications are obviously counterproductive to any weight loss effort. Some medications bring about feelings of drowsiness and lethargy. Patients taking these medications may find increased levels of physical activity exceedingly hard to maintain. Some of these medications are given in Table 6. Physicians should consider the tradeoffs of these medications when treating obese patients.
|Table 6. Medications with Weight Gain Side Effects|
|Class of Drugs||Drug Examples|
|Antidiabetics||Insulin and sulfonylureas (e.g., chlorpropamide, glipizide, and glyburide)|
|Antipsychotics||Atypical neuroleptic agents (e.g., clozapine, olanzapine, risperidone)|
|Antidepressants||Amitriptyline, imipramine, doxepin, phenelzine, amoxapine, desipramine, trazodone, tranylcypromine, lithium|
|Hormones||Estrogen and progestins|
|Adrenergic antagonists||Alpha-1 and beta-2 antagonists|
|Serotonin and histamine antagonists||Cyproheptadine|
Lack of Patient Motivation.Patients present at different levels of motivation. Meeting patients where they are and moving them through the change continuum can increase motivation. Patients should be screened for readiness to change before beginning an obesity management program, and treatment modalities should be selected accordingly. For example, the questions in Table 4 may be used to assess the patient’s readiness to change exercise behavior. If patients are in the precontemplation stage, efforts to raise their consciousness may be most helpful. Precontemplators may be defending against embarrassment, shame, or feelings of hopelessness. Providers may help precontemplators to become aware of their defenses. Providers may also help precontemplators by normalizing their feelings and expanding their options. Providers may solicit the aid of family members in this effort.
When working with patients in the contemplation stage, a provider may seek to arouse them emotionally by encouraging them to take a good hard look at themselves and asking if they are really satisfied with themselves, or if they have enough self-love to try to help themselves. If patients are in the preparation stage, the provider could encourage them to make a commitment. A written and signed agreement between the provider and the patient is a powerful technique because it personalizes the commitment and fortifies the provider-patient alliance. If patients are in the action or maintenance stage, the provider can provide kudos and suggestions regarding specific problems they may be having with the program. Using this screening technique and meeting patients where they are is an effective way of increasing motivation in patients who lack it.31
Risk of Injury During Exercise. Sedentary individuals are vulnerable to injury when activity levels are increased. These types of injuries may be dermatologic, orthopedic overuse, or the result of falls. The provider should warn patients about these potential problems and encourage them to take the necessary precautions. In general, sedentary patients should begin the program slowly to allow time for gradual physical adaptations to occur. The benefits of consistent moderate physical activity should be emphasized.
Patient Discomfort. Obese patients are likely to experience discomfort during physical activity that may negatively affect exercise adherence. For example, a recent study reported that severely obese women who were tested using walking and cycle ergometry experienced more distress than normal controls.51 These results suggest that walking, which is generally considered to be a moderate-intensity activity, may be more intense for obese individuals. Patients should be advised to select activities in a manner that anticipates and minimizes discomfort.
Patient Feelings of Hopelessness. Some patients may feel powerless to lose weight because of previous failures and/or a belief in their genetic destiny to be obese. Effective treatment planning includes resources to identify and restructure these types of distorted and counterproductive cognitions. Continuous provider reinforcement is useful as well as patient participation in supportive group activities with members that model the desired behavior and results.
Provider Bias. Patient-provider alliance building is an effective method of improving program compliance.41 Provider preconceptions and bias regarding obese people may prevent the development of a strong alliance.52 There is considerable research showing that discrimination against the obese exists in our society. Providers should be aware of the possibility that they may carry negative feelings toward obese patients that might come out during patient visits. Obese patients may be more sensitive to interpersonal cues because of the discrimination they experience.
Strategies to Promote Adherence
Table 7 lists some important strategies that help patients adhere to obesity management programs. These strategies include suitable selection of treatment modalities, self-awareness, frequent follow-up, access to a support system, access to information and education, realistic goals, anticipation, and commitment.
|Table 7. Strategies to Promote Adherence|
|• Selection of suitable treatment modalities|
|• Frequent clinical and weigh-in visits|
|• Social support|
|• Education about obesity|
|• Develop collaborative provider/patient relationship|
|• Model the behaviors|
Selection of suitable treatment modalities should be done in conjunction with the patient. Screening for depression and readiness to begin a change program are appropriate first steps. Understanding the patient’s likes, dislikes, motivations, and time and resource constraints can facilitate constructive problem-solving and lead to feasible program plans. If the patient has chosen unrealistic goals, the provider might try changing the terminology to remove the emotion from the situation. For example, if an obese person is ashamed of the amount of weight gained and is adamant about losing 100 lbs in six months, the provider might try changing the terminology from pounds to BMI units. Focusing on the reduction of BMI units might eliminate some of the shame-based pressure felt by the patient to "lose weight."
Obesity is notoriously refractory, so it is likely that some form of continuous or intermittent long-term care model will be needed for most obese patients. Patients will benefit from frequent clinical and weigh-in visits. The more weigh-in visits, the better the results. Organizing weight management groups that meet weekly and are facilitated by members of the primary care team is an effective way of getting patients in for frequent weigh-ins.
Social support can motivate patients to persevere when they might otherwise falter. Frequent exposure to like-minded individuals may encourage the patient to want to emulate the behavior of dedicated people in the group. When patients have a support group, they have somewhere to go with their problems, where people care and will listen to them and offer suggestions and comfort. Peer support is useful in promoting adherence. Providers can help patients reach their goals by encouraging them to create a plan that involves social support and by organizing weight management groups facilitated by members of the primary care team.
Primary care providers can help patients stay on track by providing education about obesity and strategies to deal with barriers to adherence. Education might consist of pamphlets describing healthy eating or exercise guidelines. Even information about the illnesses associated with obesity might be helpful in motivating some patients to stay the course. Strategies to address exercise boredom or eating out are useful to patients adhering to a weight loss program. For example, if patients are bored with their exercise program, the provider might help them identify options or emphasize decreasing sedentary activity (e.g., cut down on the time watching television), rather than increasing physical activity. If patients are having difficulty sticking to the dietary guidelines because they eat out frequently, the provider might suggest that they focus on portion sizes when the options are limited.
Providers should focus on developing collaborative relationships with patients and seek their full support for the success of the program. This can be facilitated by contracting with patients in writing to formalize their agreement to participate fully in the obesity management effort.
Finally, providers would do well to model the behaviors that they request of their patients. Patients are more likely to accept advice from providers whom they feel are practicing what they preach.
Obesity is a chronic disease for which there is no cure. Its management requires eternal vigilance. Currently available management strategies can help obese patients improve their health and well-being. We need to increasingly turn our attention to general preventive approaches to reduce continued weight gain in our patients and to target intervention approaches in a manner that will result in the greatest benefit.
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Physician CME Questions
9. The Body Mass Index (BMI) is defined in metric terms as:
10. Overweight is defined as a BMI of:
11. Obesity is defined as a BMI of:
12. What percent of the adult U.S. population is overweight or obese?
13. What is a realistic weight loss from baseline for most patients over six months?
14. What is the most helpful lifestyle change strategy?
b. Stimulus control
c. Cognitive restructuring
d. Social support
15. Orlistat is contraindicated in patients with what condition?
a. Chronic malabsorption syndrome
c. Type 2 diabetes
16. Sibutramine is contraindicated in patients with what condition?
a. Chronic malabsorption syndrome
b. Uncontrolled hypertension
c. Type 2 diabetes
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