> Table of Contents > Obesity
Obesity
Maya Leventer-Roberts, MD, MPH
image BASICS
DESCRIPTION
  • Obesity is the state of excess adipose tissue, frequently characterized in adults by body mass index (BMI), body weight (kg)/(body height [m2]), of ≥30 kg/m2.
  • Obesity is associated with negative health outcomes (1), and the concurrent presence of abdominal obesity increases the risk of morbidity and mortality.
  • System(s) affected: endocrine/metabolic, cardiac, respiratory, gastrointestinal, musculoskeletal, dermatologic, mental health
  • Synonym(s): overweight; adiposity
Geriatric Considerations
Note: Underweight BMI (≤18) is associated with an increased risk of mortality. The most likely explanation is that this is a secondary effect; severe chronic conditions can cause anorexia and weight loss.
EPIDEMIOLOGY
  • Predominant age: Incidence rises in the early 20s.
  • Predominant sex: female > male
Prevalence
  • Mean prevalence of obesity among adults is 35% in the United States (2,3).
  • Overweight: 40% of men and 25% of women
  • Obese: 20% of men and 25% of women
Pediatric Considerations
  • Pediatric obesity is defined as have a BMI at ≥95th percentile, as by age and sex specific WHO or CDC growth curves.
  • Obesity during adolescence and young adulthood is strongly associated with obesity in adulthood.
ETIOLOGY AND PATHOPHYSIOLOGY
  • Obesity is caused by an imbalance among food intake, absorption, and energy expenditure.
  • Underlying organic causes include psychiatric disturbances, hypothyroidism, hypothalamic disorders, insulinoma, and Cushing syndrome.
  • Medications can contribute to obesity, including corticosteroids, neuroleptics (particularly atypical antipsychotics), and antidepressants.
Genetics
  • Genetic syndromes such as Prader-Willi and Bardet-Biedl are found in a minority of people with obesity.
  • Studies are insufficiently powered to isolate specific genes as independent predictors of obesity.
RISK FACTORS
  • Parental obesity
  • Sedentary lifestyle
  • Consumption of calorie-dense food
  • Low socioeconomic status
  • >2 hours per day of television viewing
GENERAL PREVENTION
  • Encourage at least 1 hour of daily exercise, limited television viewing, and moderation in portion size.
  • Avoid calorie-dense and nutrient-poor foods such as sweetened beverages and processed foods.
image DIAGNOSIS
PHYSICAL EXAM
  • Elevated BMI:
    • Overweight: BMI = 25 to 29.9 kg/m2
    • Obese: BMI 30 to 39.9 kg/m2
    • Morbid obesity: BMI ≥40 kg/m2
  • Abdominal circumference:
    • Measuring around the abdomen at the level of the umbilicus.
      • Elevated:
        • Male: >40 inches (102 cm)
        • Female: >35 inches (88 cm)
DIAGNOSTIC TESTS & INTERPRETATION
  • Yearly screening and laboratory assessment (4)[C]
  • Screen for underlying physiologic causes as well as associated comorbid conditions.
  • Labs should be done while fasting (nonfasting labs within normal limits are considered adequate).
  • Preserved glucose, total insulin, hemoglobin A1C
  • Serum lipid panel
  • Thyroid function tests
  • LFTs
  • Imaging interpretation
    • Hypertrophy and/or hyperplasia of adipocytes
    • Cardiomegaly
    • Hepatomegaly
image TREATMENT
GENERAL MEASURES
  • Begin with the following assessment:
    • Motivation to lose weight (5)[A]
    • Patient-specific goals of therapy
    • Referral for intensive counseling for diet, exercise, and behavior modification
    • Long-term follow-up plan
  • Goal for therapy is to achieve and sustain long-term weight loss up of at least 10% of body weight.
  • Tracking of caloric intake and exercise
  • Use of commercial weight loss programs (e.g., Weight Watchers) can be more effective than “standard of care” counseling (6)[B].
  • Behavior therapy and cognitive-behavioral methods can result in modest weight loss but are most effective when combined with dietary and exercise treatments.
MEDICATION
  • National Institute of Health guidelines suggest nonpharmacologic treatment for at least 6 months (5)[C].
  • Medication treatment may be initiated for unsatisfactory weight loss in those with:
    • BMI ≥30
    • BMI ≥27 combined with associated risk factors (e.g., coronary artery disease, diabetes, sleep apnea, hypertension, hyperlipidemia)
  • Diet, exercise, and behavior therapy must be included with pharmacologic treatment for those without comorbid conditions.
  • Relapse may occur after discontinuation of medication.
  • Treatment for comorbidities (such as diabetes and hyperlipidemia) should be considered.
First Line
  • Medications may produce modest weight loss (7)[B].
  • The lipase inhibitor orlistat (Xenical) decreases the absorption of dietary fat. Dose: 120 mg PO TID with meals containing fat; omit dose if meal is skipped or does not contain fat. Patients must avoid taking fat-soluble vitamin supplements within 2 hours of taking orlistat. The FDA has approved orlistat (Alli) 60 mg PO TID to be sold over the counter as a weight loss aid (8)[B]; adverse effects mainly GI (cramps, flatus, fecal incontinence)
  • Contraindications
    • Orlistat: chronic malabsorption syndromes, cholestasis, pregnancy
Second Line
  • Appetite suppressants recommended for short-term treatment (≤6 months) (9)[A]
  • Only beneficial in patients who exercise and eat reduced calorie diet
    • Naltrexone/bupropion (Contrave): 8 mg naltrex-one/90 mg bupropion per tablet; slow titration up to 2 tablets PO BID by week 4; contraindicated if uncontrolled HTN, seizure disorder, chronic opioid use, pregnancy
    • Liraglutide (Saxenda): 1.203 mg SC once daily; GLP-1 agonist recently approved for obesity; discontinue if weight loss is <4% after 16 weeks.
    • Topiramate: Initiate with 25 mg BID and increase by 50 mg/week up to 100 mg PO BID; not FDA-approved for the treatment of obesity; tolerance is a concern (paresthesias, somnolence, difficulty concentrating).
  • Schedule IV drugs
    • Lorcaserin (Belviq) 10 mg PO BID (D/C if weight loss is <5% after 12 weeks); works as serotonin agonist; avoid in those with CrCI <30 mL/min; contraindicated in pregnancy; avoid use with other serotonergic drugs.
    • Phentermine: 15, 30, 37.5 mg PO every morning; discontinue if tolerance or no response after 4 weeks; contraindicated if history of CV disease, hyperthyroidism, history of substance abuse, pregnancy
    • P.723

    • Phentermine/topiramate (3.75 to 23 mg, 7.5 to 46 mg, 11.25 to 69 mg, 15 to 92 mg); initiate 3.75 to 23 mg PO once daily; requires enrollment into Risk Evaluation and Mitigation Strategy (REMS); women of childbearing age require negative pregnancy test prior to initiation and monthly thereafter
    • Diethylpropion: 25 mg PO before meals TID; discontinue if no response after 4 weeks. Contraindicated if severe HTN, hyperthyroidism, history of substance abuse
Pregnancy Considerations
During pregnancy, obese women should gain fewer pounds than recommended for nonobese women.
SURGERY/OTHER PROCEDURES
Patients meeting criteria should be evaluated for gastric bypass or lap band procedures (10)[C].
  • Requires complex presurgical evaluation, surgery, and follow-up in a skilled treatment center.
  • Surgical treatment is the most effective long-term weight-loss treatment available for morbidly obese patients, but there is insufficient evidence on longterm outcomes (11)[A].
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
  • Exercise is an integral part of any weight loss program, yet exercise alone rarely results in significant weight loss.
  • Combination of weight training and aerobic activity is preferred over aerobic activity alone.
Patient Monitoring
Long-term routine follow-up may prevent relapse after weight loss or further weight gain.
DIET
  • Long-term studies suggest net calorie reduction of 500 to 1,000 kcal/day and ease of use are more important than the diet composition for long-term results (12)[A]:
    • A reduction of 500 kcal/day intake can result in ˜1 lb (0.45 kg) weight loss per week.
    • Portion-controlled servings are recommended.
  • Very low-calorie diet (400 to 800 kcal/day consumption)
    • Can result in more rapid weight loss than higher calorie diets but are less effective in the long term
    • Complications can include dehydration, orthostatic hypotension, fatigue, muscle cramps, constipation, headache, cold intolerance, and relapse after discontinuation.
    • Contraindications: recent myocardial infarction or cerebrovascular accident, renal disease, cancer, pregnancy, insulin-dependent diabetes mellitus, and some psychiatric disturbances
PATIENT EDUCATION
  • Emphasize the value of a healthy BMI.
  • Recommended Web site:
    • www.nal.usda.gov/fnic/foodcomp/search for the FDA nutritional content in common foods
PROGNOSIS
  • Lowest mortality associated with a BMI of 22
  • Long-term maintenance of weight loss is difficult to achieve.
  • A motivated patient is most likely to achieve successful weight loss (13).
REFERENCES
1. Flegal K, Graubard B, Williamson D, et al. Excess deaths associated with underweight, overweight, and obesity. JAMA. 2005;293(15):1861-1867.
2. Ogden CL, Carroll MD, Flegal KM. Prevalence of obesity in the United States. JAMA. 2014;312(2): 189-190.
3. Ogden CL, Carroll MD, Fryar CD, et al. Prevalence of obesity among adults and youth: United States, 2011-2014. NCHS Data Brief. 2015;(219): 1-8.
4. National Heart, Lung and Blood Institute, National Institutes of Health, U.S. Department of Health and Human Services. Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults: the evidence report. Bethesda, MD: National Institutes of Health; 1998. NIH Publication 98-4083.
5. Shaw K, O'Rourke P, Del Mar C, et al. Psychological interventions for overweight or obesity. Cochrane Database Syst Rev. 2005;(2):CD003818.
6. Jebb SA, Ahern AL, Olson AD, et al. Primary care referral to a commercial provider for weight loss treatment versus standard care: a randomised controlled trial. Lancet. 2011;378(9801): 1485-1492.
7. Padwal R, Li SK, Lau DC. Long-term pharmacotherapy for obesity and overweight. Cochrane Database Syst Rev. 2004;(3):CD004094.
8. Kramer CK, Leitão CB, Pinto LC, et al. Efficacy and safety of topiramate on weight loss: a metaanalysis of randomized controlled trials. Obes Rev. 2011;12(5):e338-e347.
9. Dombrowski SU, Knittle K, Avenell A, et al. Long term maintenance of weight loss with non-surgical interventions in obese adults: systematic review and meta-analyses of randomised controlled trials. BMJ. 2014;348:g2646. doi:10.1136/bmj.g2646.
10. Colquitt J, Clegg A, Loveman E, et al. Surgery for morbid obesity. Cochrane Database Syst Rev. 2005;(4):CD003641.
11. Puzziferri N, Roshek TB III, Mayo HG, et al. Long-term follow-up after bariatric surgery: a systematic review. JAMA. 2014;312(9):934-942.
12. Thomas DE, Elliott EJ, Baur L. Low glycaemic index or low glycaemic load diets for overweight and obesity. Cochrane Database Syst Rev. 2007; (3):CD005105.
13. Ogden LG, Stroebele N, Wyatt HR, et al. Cluster analysis of the national weight control registry to identify distinct subgroups maintaining successful weight loss. Obesity (Silver Spring). 2012;20(10):2039-2047.
Codes
&NA;
ICD10
  • E66.9 Obesity, unspecified
  • E66.3 Overweight
  • R63.5 Abnormal weight gain
Clinical Pearls
&NA;
  • Drug treatment with a first-line medication may be indicated when nonpharmacologic treatment for 6 months has been ineffective and the patient has a BMI >30 or a BMI >27 with associated risk factors. Medications may achieve a modest longterm weight loss.
  • Surgical treatment may be indicated in patients with a BMI >40 who have failed more conservative treatment, particularly when there are associated risk factors, such as diabetes mellitus.
  • No convincing evidence supports a specific diet method.