MANAGING OBESITY
From the 39th Annual Advances and Controversies in Clinical Pediatrics, presented by the Department of
Pediatrics, University of California, San Francisco, School of Medicine
| FAD DIETS: THE MYTHS AND REALITIES—Andrea K. Garber, PhD, RD, Assistant Adjunct Professor of Pediatrics,
University of California, San Francisco, School of Medicine
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 | “Holy Grail” of diets: endorsed by—American Heart Association (AHA); National Cholesterol Education Program
(NCEP)
|
| Women’s Health Initiative (WHI): almost 50,000 women 50 to 79 yr of age; findings—after almost 8 yr, women lost only
1.9 kg; no significant reduction in cancer risk or incidence of cardiovascular disease; problems with study—group
never achieved <24% of calories from fat; difficult to achieve very low-fat diet without excluding animal products; consider
plant-based low-fat diet (eg, Ornish diet); women postmenopausal (effect possibly better if diet started earlier in life);
disappointing results suggest that low-fat diets not panacea
|
| Heart-healthy fats: poly- and monounsaturated fats (olive and canola oils, nuts, seeds, peanut butter, avocado); long-
chain fats (fish, flaxseed); unhealthy fats—bacon and butter; trans fats in almost all processed foods; choose lean
meats and plant proteins
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| Low-carbohydrate, high-fat diet: goal <20 g of carbohydrate/day (<3% of total calories; primarily from salad and vegetables)
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| Low carbohydrate vs low fat (clinical trial): low-carbohydrate diet significantly more effective for weight loss at 3 and 6
mo (by 12 mo, groups equal); high-density lipoprotein (HDL) improved and triglycerides lowered on low-carbohydrate
diet; blood pressure (BP) and insulin resistance improved on both diets
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| Advice: explain why diet works short term and concerns long term; describe benefit of limiting sugars, starches, sodas,
chips, candy; high-fat diet inconsistent with long-term cardiovascular health; encourage fruits, vegetables, and low-fat
or soy milk
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| Low glycemic index (GI) diets (South Beach diet; Sugar Busters; Zone diet)
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| Low starch and low sugar (not low carbohydrate): menu least objectionable compared to other fad diets; GI—classifies
foods according to carbohydrate availability; high-GI foods (high in sugar and starch; eg, bagel, watermelon, pineapple);
low-GI foods (legumes, whole grains, vegetables, some fruits); fiber decreases GI (slows glucose absorption;
wheat bran protects starchy endosperm from digestion); white bread vs lentils—lower rise in blood glucose with
lentils (mostly due to fiber content); glycemic load—more useful concept; takes into account serving size
|
| Study by Ludwig: adolescent subjects consumed low-, medium-, and high-GI breakfast, then ad libitum lunch; glucose
and insulin response as well as glucagon and counterregulatory hormones measured; feeding response—with high-
GI breakfast, rise in glucose and insulin much higher by comparison, then falls below baseline at 4 to 5 hr (subclinical
hypoglycemia may contribute to hunger); fasting response—glucagon fasting hormone (fuels body between meals;
suppressed with high-GI meal); fatty acids important fuel between meals (suppressed at 4 hr); counterregulatory
hormones—huge surge in plasma epinephrine and growth hormone with high-GI meal; findings—at lunch, high-
GI group consumed 81% more calories than low-GI group
|
| Advice: low-GI diet better option among fad diets; lowers body mass index (BMI; weight (kg)/[height (m)]2 ) and fat
mass and improves insulin resistance; may be helpful for patients displaying metabolic syndrome with impaired glucose
tolerance
|
| Adolescents who diet: at greater risk of developing eating disorder; more likely to engage in other risky behaviors (eg,
smoking, alcohol use, sexual activity); more likely to be overweight in future
|
| Best nutrition advice (Willett): eat more—heart-healthy fats, fruits, vegetables, and whole grains; eat less—
saturated fat and trans fat from processed snack foods; refined starches and added sugars; do not drink—soda or juice
(more calories than soda)
|
| Weight Assessment for Teen and Child Health (WATCH) clinic healthy-plate pie chart: one quarter
whole grain; one quarter lean protein (fish, poultry, beans, nuts, eggs, seeds, tofu, peanut butter); one half fruits and vegetables
(2 or 3 servings at every meal); also—essential fats (canola or olive oil); glass of low-fat or soy milk with every
meal
|
| METABOLIC COMPLICATIONS OF OBESITY —Dennis M. Styne, Professor of Pediatrics and Rumsey Chair of Pediatric
Endocrinology, University of California, Davis, School of Medicine
|
| Risk factors for obesity in adulthood: if adolescent >13 yr of age and obese, risk >50% of being obese adult; if one or
both parents obese, much greater risk of becoming obese later in life (family history more predictive than weight of child)
|
| Early puberty: childhood obesity linked to early puberty, and some longitudinal studies show that early puberty associated
with obesity in adulthood; increased risk for breast cancer unequivocally linked to early menarche
|
| Hypertension: measure BP properly (frequently, results of automated systems fallaciously high); white-coat hypertension;
make sure cuff proper size; BP related to height, sex, and age; treatment—lifestyle modification; diuretics (particularly
thiazide diuretics) only medications not associated with some risk in pregnancy; most obese children do not have hypertension
|
| Lipid levels rising: values may be elevated within first 10 yr of life; histologic changes in coronary arteries visible in
childhood; fasting blood levels—total cholesterol should be <170 mg/dL (>200 mg/dL high); HDL should be >45
mg/dL (<35 mg/dL too low); triglycerides vary by age, but should be <75 mg/dL in children <10 yr of age (<90 mg/dL
later); lipid levels in obese children usually do not require treatment (perhaps standards will be lowered with longer-
term follow-up)
|
| First step: refer to dietitian; if child >10 yr of age (sometimes as young as 6 yr) and low-density lipoprotein (LDL) ≥190 mg/dL
or elevated sufficiently with risk factors (eg, early death in family, hypertension), consider medical therapy
|
| Medical therapy: lipid-binding resins (approved for children ≥6 yr of age); niacin (not approved for managing hyperlipidemia
in children); statins—no large or long-term studies in children; no proof of long-term effect on lipid levels in
children; teratogenic (sexually active girls must use contraception); in small studies, safe and helpful; not many obese
children need them
|
| Treatment goals (American Diabetes Association [ADA]): normal fasting blood glucose 100 mg/dL (>126 mg/dL evidence
of diabetes); normal 2-hr postprandial blood glucose <140 mg/dL (>200 mg/dL evidence of diabetes)
|
| Study: significantly obese adolescents and preadolescents; findings—24% of prepubertal group had impaired glucose tolerance;
of adolescents, 4% had silent diabetes; follow-up—children with normal glucose tolerance test (within 2 yr, 9.5% developed
impaired glucose tolerance); of those with impaired glucose tolerance, at 20 mo, 30% same (45% normalized, but
24% developed type 2 diabetes); impaired glucose tolerance may be marker for development of diabetes; progression within
2 yr (slower in adults); type 2 diabetes develops more quickly in children once they manifest likelihood to develop it
|
| Impaired glucose tolerance: can progress quickly to type 2 diabetes; severely obese children (BMI >95th percentile for
age) with parent who has type 2 diabetes or history of gestational diabetes should undergo glucose tolerance test; blood
glucose >140 mg/dL indication for most intensive intervention (most exercise and greatest change in diet); no medical
treatment available
|
| First-line treatment: diet and exercise (unless patient ketotic or diabetic ketoacidosis [DKA] present)
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| Medical treatment: insulin—used emergently if DKA present (patients weaned off if type 2 diabetes strongly suspected);
oral hypoglycemic agents—metformin best studied and most useful (does not cause hypoglycemia); adjunctive
therapy—other hypoglycemic agent; insulin
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| Physical activity: study—if children exercise (even those in worst shape), serum insulin decreases and insulin resistance
improves; even 20 min/day, few days weekly can affect insulin resistance; study by Nassis—exercise improves
insulin sensitivity
|
| Metabolic syndrome (syndrome X; insulin resistance syndrome) in adolescents: components—
hyperlipidemia; hypertension; renal impairment; prevalence in 12- to 19-yr-olds (National Health and Nutrition
Examination Survey [NHANES] III; Cook et al)—up to 7% of white and Hispanic boys already have metabolic
syndrome during early teenage years; Bogalusa Heart Study—children with highest BMI at greatest risk of developing
metabolic syndrome (patients with highest insulin secretion rate also at risk); some patients in lowest quartile of insulin secretion
and BMI still developed metabolic syndrome
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| Polycystic ovary syndrome (PCOS)
|
| Treatment: weight loss and dietary changes primary intervention; oral contraceptives; metformin—insulin resistance medication;
in several studies, can decrease insulin resistance, decrease weight, reduce androgen secretion, and allow menstruation;
may be useful adjunct for weight loss (studies ongoing); lifestyle modification (longitudinal study)—
20 young women exercised and consumed optimal diet; changes led to ovulation; subjects highly motivated to exercise
and eat right (they wanted children)
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| Laboratory examination: if BMI in 85th to 90th percentile for age but no risk factors, get fasting lipid profile; if BMI >95th
percentile, liver function test and lipid profile; ADA—at 10 yr of age (or onset of puberty) and every 2 yr thereafter, with
family history of diabetes, obtain fasting blood glucose
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| TIPPING THE SCALES: SPECIAL CONSIDERATIONS IN ATHLETIC ACTIVITY FOR THE OBESE CHILD —
Anthony C. Luke, MD, Assistant Professor of Orthopedic Surgery and Family and Community Medicine, University of
California, San Francisco, School of Medicine
|
| Musculoskeletal considerations in overweight child athlete: slipped femoral capital epiphysis—
associated with increased BMI (especially bilateral condition); malalignment—Blount’s disease (severe tibia varum;
sometimes requires surgery); patellofemoral pain overuse problem; tendinopathy (in, eg, Achilles tendon); osteochondritis
dissecans (no evidence of increased incidence in overweight children); altered biomechanics—walking and riding
exercise cycle require more energy expenditure and effort because of mechanical inefficiency
|
| Cardiorespiratory fitness (CRF): assessment—see how far patient can run or walk for 12 min; in recent study,
overweight population able to walk only two-thirds distance controls could walk (reflects peak maximum O2 consumption);
exercise tolerance—increased cardiorespiratory demands due to increased mass; study by Nassis—children
with high CRF have lower body fat percentage and smaller skin-fold thickness; study by Falkner—higher BMI associated
with higher systolic and diastolic BPs in children 2 to 19 yr of age
|
| Heat illness: obese children thermoregulate more poorly than leaner subjects; football—athletes (who may be deconditioned)
start practicing in summer heat wearing equipment which traps heat; heavy lineman particularly at risk for fatal
event
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| What we can do: sports selection; good nutrition; weight loss activities; ask patient, “what do you like to do?”; high percentage
of teenage girls inactive
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| Activities to recommend: for heavier child, size often advantage in football, basketball, or baseball; track and field
(throwing sports require power); wrestling and martial arts; for girls, dance groups, hip hop dancing, low-impact aerobics;
cheerleading and dance squads; individual sports—swimming good cardiovascular exercise (easy on joints);
weight training—safe in children, especially with proper supervision and education on proper techniques; increases
lean body mass (helps caloric expenditure)
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| Amount of exercise: common recommendation 30 to 60 min of moderate-to-high intensity exercise daily (not based on
hard science); in recent analysis, 180 min/wk of moderate-to-high intensity exercise effective for weight loss (long-term
effect not known); Surgeon General recommends 60 min of physical activity almost every day for young people; best
way to find time for physical activity—lower amount of television watching and computer use
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| Counseling: help patient think of physical activity in positive way; understand patient’s activities; discuss sports selection;
assess maturity (amount of activity must be appropriate to maturity level; some children doing too much for age);
follow-up—monitor risks; make sure patient enjoying activities and not having problems; education—important for
athletes, parents, and coaches
|
| Ankle sprain (study): overweight risk factor for poorer outcome; overweight children more likely to complain of persistent
symptoms after 6 mo
|
| Role of primary care physician: barriers to care (survey by Story)—lack of patient motivation; lack of parent
involvement; lack of clinician time; study by Luke—counseling variable; need more research on effective interventions
and counseling techniques; improving patient compliance—written handout with instructions; focused visit
for physical activity counseling; exercise with another person; know resources available in community; weight loss more
successful when parent actively involved; monitoring success—use activity diary (provides something tangible to
discuss to encourage and reinforce positive behaviors); counting steps instead of calories—in recent study, girls
walk 12,000 steps/day (boys, 15,000 steps/day); use pedometer to get average of child’s daily number of steps (average
from 4 days); 1000 steps equals 10 min of brisk walking; challenge patient to increase average scores weekly
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Educational Objectives
| The goal of this program is to educate the listener about managing childhood obesity. After hearing and assimilating this
program, the clinician will be better able to:
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| 1. Weigh the advantages and disadvantages of fad dieting.
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| 2. Describe healthy nutritional approaches to weight loss.
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| 3. Recognize metabolic complications of obesity.
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| 4. Choose appropriate therapy for metabolic complications of obesity.
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| 5. Identify special medical considerations in the obese athlete.
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Discussed on This Program
Insulin injection, concentrated [Humulin R Regular U-500 (concentrated)]
Insulin injection, regular [Humulin R, Novolin R, Novolin R PenFill, Novolin R Prefilled, Iletin II Regular, Velosulin BR]
Insulin lispro, human (rDNA) [Humalog, Humalog Mix 75/25]
Insulin suspension, isophane (NPH) [Humulin N, Novolin N, Novolin N PenFill, Novolin N Prefilled, NPH Iletin II]
Insulin suspension, isophane (NPH) and insulin injection, regular [Humulin 50/50, Humulin 70/30, Novolin 70/30, Novolin
70/30 PenFill, Novolin 70/30 Prefilled]
Metformin HCl [Fortamet, Glucophage, Glucophage XR, Riomet]
Niacin (B3 ; nicotinic acid) [Niacor, Niaspan, Slo-Niacin]
Suggested Reading
Adelman RD et al: Proteinuria and focal segmental glomerulosclerosis in severely obese adolescents. J Pediatr
138:481, 2001; Atlantis E et al: Efficacy of exercise for treating overweight in children and adolescents: a systematic review.
Int J Obes (London) 30:1027, 2006; Bravata DM et al: Efficacy and safety of low-carbohydrate diets: a systematic
review. JAMA 289:1837, 2003; Chan CB et al: Health benefits of a pedometer-based physical activity
intervention in sedentary workers. Prev Med 39:1215, 2004; Council on Sports Medicine and Fitness; Council
on School Health: Active healthy living: prevention of childhood obesity through increased physical activity. Pediatrics
117:1834, 2006; Drinkard B et al: Relationships between walk/run performance and cardiorespiratory fitness in
adolescents who are overweight. Phys Ther 81:1889, 2001; Ebbeling CB et al: A reduced-glycemic load diet in the
treatment of adolescent obesity. Arch Pediatr Adolesc Med 157:773, 2003; Falkner B et al: The relationship of
body mass index and blood pressure in primary care pediatric patients. J Pediatr 148:195, 2006; Hedley AA et al:
Prevalence of overweight and obesity among US children, adolescents, and adults, 1992-2002. JAMA 291:2847, 2004;
Knowler WC et al: Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J
Med 346:393, 2002; Lawlor DA et al: Association of body mass index measured in childhood, adolescence, and young
adulthood with risk of ischemic heart disease and stroke: findings from 3 historical cohort studies. Am J Clin Nutr
83:767, 2006; Ludwig DS et al: High glycemic index foods, overeating and obesity. Pediatrics 103:E26, 1999; Luke
A et al: Physical inactivity in children and adolescents: CASM AdHoc Committee on Children’s Fitness. Clin J Sport
Med 14:261, 2004; Nassis GP et al: Aerobic exercise training improves insulin activity without changes in body
weight, body fat, adiponectin, and inflammatory markers in overweight and obese girls. Metabolism 54:1472, 2005; National
High Blood Pressure Education Program Working Group on High Blood Pressure in Children
and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children
and adolescents. Pediatrics 114:555, 2004; Sinha R et al: Prevalence of impaired glucose tolerance among children
and adolescents with marked obesity. N Engl J Med 346:802, 2002; Srinivasan SR et al: Predictability of childhood
adiposity and insulin for developing insulin resistance syndrome (syndrome X) in young adulthood: the Bogalusa Heart
Study. Diabetes 51:204, 2002; Story MT et al: Management of child and adolescent obesity: attitudes, barriers, skills,
and training needs among health care professionals. Pediatrics 110:210, 2002; Styne DM: Obesity in childhood: what’s
activity got to do with it? Am J Clin Nutr 81:337, 2005; Styne DM: Obesity. In Pediatric Endocrinology: A Practical
Clinical Guide (Radovick S, Macgillivray MH, eds). Humana Press, Totowa, NJ, 2003; Willett W, Skerrett PJ: Eat,
Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. Free Press (Simon and Schuster): New York,
NY, 2005.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant financial
relationship with the manufacturer or provider of any commercial product or service discussed. For this issue, the faculty
reported nothing to disclose.
Drs. Garber, Styne, and Luke were recorded at the 39th Annual Advances and Controversies in Clinical Pediatrics
, presented June 1-3, 2006, in San Francisco, CA, by the Department of Pediatrics, University of California, San Francisco,
School of Medicine. The Audio-Digest Foundation thanks the speakers and the University for their cooperation in the
production of this program.
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