Evaluation and Management of Obesity
All children with a BMI greater than the 85th percentile and severely obese children younger than 2 years and those of any age rapidly gaining excessive weight need evaluation. The history focuses on family weight tendencies, obesity-related complications (see Table 24-46), and exclusion of other diseases or syndromes that may be associated with obesity.
A history of headaches or neurologic symptoms, evidence of polyuria and polydipsia, or evidence of a psychopathologic condition may indicate a central nervous system tumor. Constipation, cold intolerance, and dry skin may suggest hypothyroidism. Linear growth failure is uncommon among obese children, who usually are tall for age. Cushing syndrome, pseudohypoparathyroidism, and hypothalamic lesions must be considered if the child is short and obese.
Developmental delay should lead to consideration of the many syndromes associated with obesity (see Table 24-47). The child’s activity level, television watching, and dietary history are reviewed. The physical examination is focused on blood pressure, BMI, distribution of fat, optic disc contour, and the presence of acanthosis nigricans. Laboratory evaluation may be needed to exclude the causes of obesity discussed earlier. If none of these causes is suspected, the appropriate laboratory evaluation is directed at screening for complications of obesity. For a child with a BMI in the 85th to 94th percentile, only a fasting lipid profile is recommended unless the risk factors include cigarette smoking, the presence of diabetes mellitus, low physical activity, high blood pressure, a family history of early cardiovascular disease, or a family history that suggests diabetes or hyperlipidemia. In such cases, and for all children with a BMI greater than 95th percentile, laboratory evaluation includes a fasting lipid profile; fasting insulin and glucose; measurement of liver transaminases, calcium, and phosphorus; and an electrocardiogram. Depending on the history and physical findings, a Holter monitor study, extremity radiographs for orthopedic complications, thyroid function tests (free T4 and TSH), morning cortisol or dexamethasone suppression test, or a sleep study to assess respiratory complications may be indicated.
Obese children and their families need counseling regarding the risks of obesity. It is important that the health-care professional candidly discuss the effects of being overweight on the child’s self-image and social interactions. It is useful to discuss the genetic predisposition to obesity and to recognize the challenges of a weight loss regimen. The following discussion is directed specifically at management of obesity. Therapy for comorbid conditions are not addressed.
Mild, uncomplicated cases of obesity usually can be approached in the primary physician’s office. Severe or complicated cases necessitate a comprehensive approach, which is available in relatively few centers. The goals of a weight management program are improvement of medical and psychological health and prevention of comorbidities of obesity. Modification of diet and activity and behavior therapy are the essential components of a program aimed at a lasting effect. Weight management programs are less successful if there are delayed recognition of the weight problem, unrealistic expectations, lack of specific recommendations, lack of follow-up and maintenance programs, negative counseling techniques, and lack of readiness of the child and family. Adult weight control programs are not appropriate for children. A group program, such as the Shapedown Pediatric Obesity Program (http://www.shapedown.com), a structured weight loss and weight management program for children between the ages of 6 and 20 years, is aimed at children and adolescents. Obesity is best considered a chronic disease requiring constant awareness of food choices and activity levels. Treatment is aimed at acquiring healthful daily habits. A practitioner who is frustrated by the problem or prejudiced against obese persons and family or who has inadequate time to attend to the problem should not attempt treatment.
NUTRITION EDUCATION: A change in diet that maintains weight stability or promotes slow weight loss is the most reasonable approach for most children. Weight loss goals should be obtainable and should allow for normal growth. Goals initially are small, so that the child does not become overwhelmed or discouraged. Two kilograms to 4 kg is a reasonable first goal; if preferred, a rate of 0.5 to 2 kg a month can be established. Lessons on healthful eating, portion control, choosing appropriate foods, label reading, and modification of recipes are essential to help the family and child achieve successful weight management. Limitation of fat intake is beneficial above and beyond the effect on calories. Keeping a dietary log helps the person concentrate on desired changes. It is necessary to provide parents with a specific calorie-per-day recommendation that follows guidelines for percentages of fat, protein, and carbohydrates. Tobacco use must be discouraged; some teenagers smoke in a misguided attempt to control weight.
In the most severe cases (usually among adolescents with apparent comorbidities such as sleep apnea and pseudotumor cerebri) weight loss with a protein-sparing modified fast may be invoked. The protein-sparing modified fast is a severely caloric restricted diet of, for example, 600 to 900 kcal/d containing 1.5 to 2 g of high-biological-quality protein per kilogram per day with vitamin and mineral supplementation and considerable water (>1.5 L/d). Regular observation by a physician is essential to avoid severe complications. Carbohydrate is eliminated, so ketosis develops, which helps decrease appetite and fosters adherence to the diet. Arrhythmias are documented, so rhythm recording with a Holter monitor is performed before the fast. This program usually is limited to less than 5 months and aims for rapid weight loss, which should be maintained thereafter. Protein-sparing modified fasting rarely is indicated.
PHYSICAL ACTIVITY: A child cannot exercise enough to burn off a high-calorie diet. A children’s meal of cheeseburger, french fries, and a milk shake in a fast-food restaurants exceeds 750 calories; large-size children’s meals that exceed 1000 calories have appeared. It would take more than 1.5 to 2 hours on a ski machine or stationary bicycle to work off such a single meal. The goal is to avoid such high-calorie loads and to reduce sedentary activity rather than to encourage a regimen of exercise to which no one can adhere. Fostering activities that can be carried through life is best. Some centers suggest the use of hip-hop or other popular dances as exercise. Self-monitoring with an activity log (or inactivity log) is helpful for child and parent to understand the behaviors and make changes. Setting weekly activity goals assists a gradual increase in activity. A benefit of increased activity is limitation of the loss of fat-free mass during decreased caloric intake. The most important change a family can make is to turn off the television or electronic games or limit these activities to no more than 1 hour per day.
BEHAVIOR MODIFICATION: The essence of behavioral therapy is (1) functional analysis of the association between eating and activity behaviors and environmental events and (2) systematic modification of eating, activity, or other behaviors thought to contribute to or maintain obesity. Cognitive behavioral strategies for weight management should provide concrete skills for children and families to change the behavior and achieve a healthier lifestyle. Behavioral therapy sessions usually are conducted in small groups. A team approach to weight management is optimal; various combinations of a social worker, psychologist, dietitian, nurse, and physician participate.
The programs focus on a variety of skills that aid in altering eating and activity patterns. Enhancement of parenting skills is important so that parents do not tell children they are “bad” but rather praise healthy food choices, set consistent limits, and provide appropriate meal times without television. Using food as a reward is discouraged, and instruction on provision of healthy foods rather than junk foods is provided. The child or family keeps a diary to monitor activity and patterns of food intake. Children are taught to identify environmental cues associated with overeating and underactivity. These issues are addressed. Children are encouraged to become aware of their negative thoughts and beliefs about themselves and their weight. Stress management skills (other than eating) are taught and the child and family are taught to problem solve to facilitate healthful eating.
Family participation is essential for the program to succeed among children younger than 10 years. For teenagers, the degree of parental involvement needs to be individually assessed. In some instances, it may be counterproductive. It is also important that the treating health-care professionals be empathetic and compassionate. Physicians and others often communicate their own prejudice and poor understanding of obesity by oversimplifying the problem. Many physicians continue to believe that obesity is caused solely by gluttony or slothlike behavior that can be easily remedied if willpower is adequate.
SURGERY: Gastric bypass or banding has benefits among morbidly obese adults with sustained weight loss. Monitoring for nutritional complications of protein deficiency, malnutrition, vitamins A, D, and B12, and folic acid is important. Other complications include dumping syndrome and surgical adhesion. There is a little experience with this therapy in childhood and young adolescence. This approach therefore cannot be recommended.
MEDICATIONS: No medications have been approved as therapy for obesity among persons younger than 16 years. They are being tested on children 12 to 16 years of age. Sibutramine, a serotonin reuptake inhibitor, can be used by older adolescents to increase the feeling of satiety and decrease intake. A side effect is a slight increase in blood pressure. Orlistat is an intestinal lipase inhibitor that decreases absorption of fat. Side effects such as bloating, flatulence, and diarrhea occur if fat intake is not reduced. As the biological mechanism of appetite control and obesity is elucidated, it is expected that better targeted, safer agents will become available.
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By Dennis M. Styne, Nancy Schoenfeld-Warden
Revision date: July 9, 2011
Last revised: by Janet A. Staessen, MD, PhD