A lecture about obesity for medical students
- 1. Obesity Dr. Muhammed Khalid Hasan M.B.Ch.B / FIBMS.FM Community Department Family Medicine Unit
- 2. Outlines 1. Objectives 2. Clinical Case 3. Summary
- 3. Objectives To • Understand the etiology of obesity. • Learn the diagnostic criteria for obesity. • Know other comorbid conditions associated with obesity. • Understand the therapeutic options available for the management of obesity.
- 4. Case • A 145 Kg, 177cm, 45-year-old male comes to your office saying he feels fatigued. He has been obese all his life. He tells you that his obesity has nothing to do.
- 5. • OBESITY: An excessive amount of body fat, which increases the risk of medical illness and premature death. • Obesity is a chronic and stigmatizing disease that begins early in life. • In all persons, obesity is caused by ingesting more energy than is expended over a period of time. • Energy balance is affected by both genetic and environmental factors.
- 7. Pathogenesis (video) • In all persons, obesity is caused by ingesting more energy relative to the amount of energy expended. • Energy balance is affected by genetic, physiologic, and environmental factors. • It has been estimated that genetic background can explain 40% or more of the variance in body mass in humans. • Social factors such as lower education level, lower socioeconomic class, and diet composition are all associated with high risk of obesity. • Physiologic factors such as various gut hormones, level of spontaneous physical activity (fidgeting), and age-related decline in energy expenditure are key determinants in regulation of food intake and energy expenditure. • An increase in energy consumption with a decrease in physical activity is thought to be the main contributor to the current obesity epidemic.
- 8. Q: The hormone thought to effect appetite is: A. Adrenalin B. Resistin C. Leptin
- 9. Clinical approach A careful history to ascertain food & beverage intake Relevant questions: • Do you feel that you have excessive appetite • Tell me your typical daily meal, snacks, soft drinks & alcohol • What exercise do you get • Do you have special problem, being bored, depressed • What drugs do you use Complete physical examination (including anthropometric measurements) for complication and secondary causes of obesity.
- 10. Diagnostic Tools • BODY MASS INDEX (BMI): A measurement of the relative composition of lean body mass and body fat; calculated as weight in kilograms/(height in meters)2. • BMI is not an accurate measure of overweight/obesity in patients with heart failure, pregnant women, body builders, professional athletes, elderly and certain ethnic groups. • Waist circumference, hip circumference, waist-to-hip ratio, and 4 Skinfold thickness (biceps, triceps, subscapular, suprailiac) need to be used to accurately identify the population at risk.
- 12. • Assessing waist circumference is important because excess abdominal fat is an independent predictor of disease risk. • Android obesity (excess fat located primarily in the abdomen or upper body) places an individual at greater risk for congestive heart disease, hypertension, lipid disorders, and type 2 diabetes mellitus, whereas gynoid obesity (excess fat located primarily in the lower extremities or hips) does not.
- 14. Classification of obesity in children • Overweight: BMI between 85th & 95th percentile for age–matched & sex-matched control subjects • Obesity: BMI > 95th percentile
- 15. BMI (KG/M2) OBESITY CLASS Underweight <18.5 Normal 18.5-24.9 Overweight 25.0-29.9 Obesity 30.0-34.9 35.0-39.9 I II Extreme obesity >40 III
- 16. COMMON MEDICAL COMPLICATIONS OF OBESITY • Cardiovascular disease • Cerebrovascular disease • Hypertension • Hyperlipidemia • Type 2 diabetes mellitus • Sleep apnea • Mood disorders • Eating disorders • Cholelithiasis • Infertility/reduced fertility • Menstrual cycle irregularities • Polycystic ovary syndrome • Degenerative joint disease • Malignancies
- 17. • Strongest associations are between obesity and hypertension and obesity and diabetes. • Weight loss in an obese individual reduces blood pressure, hemoglobin A1c, triglyceride, low-density lipoprotein, and total cholesterol levels, and it increases high-density lipoprotein levels • In general, greater BMI is associated with more health complications and grade II or higher obesity is associated with greater risk of mortality. • Also, the more complications that develop, the more difficult it becomes to manage the underlying obesity. For example, a person with degenerative arthritis and heart disease may have significant symptoms during exercise, impairing his or her ability to expend more energy in an effort to lose weight.
- 19. Screening for medical conditions that may promote obesity 1. Endocrine disorders that promote weight gain, such as thyroid disease, polycystic ovarian syndrome, and Cushing syndrome. 2. Many medications are associated with weight gain, including corticosteroids, insulin or insulin secretagogues, antiepileptics, anxiolytics, antidepressants, and antipsychotics.
- 21. Investigation Focused laboratory workup should be performed to look for complications and comorbid conditions. • CBC • FBS • Fasting lipids profile • TSH • Liver enzymes for fatty liver.
- 22. Treatment 1. The primary goal of treatment should be weight loss of at least 10% of initial body weight. 2. Maintenance of this new weight is the next priority. • Treatment of obesity should begin in patients with a BMI greater than 25 or who have visceral obesity, documented by increased waist circumference greater than 102 cm (40 in) in men and greater than 88 cm (35 in) in women or a waist-to- hip ratio greater than 0.9 in men and greater than 0.85 in women.
- 23. The weight loss program must contain these essential components: (1) Nutritionally balanced diet, (2) Aerobic and strengthening exercise, (3) Reduction in the percentage of calories derived from fat. Reducing the percentage of calories derived from fat (compared with carbohydrates and proteins) by itself produces weight loss. (4) Behavioral therapy, and (5) Making weekly office visits for a period of 8 to 12 weeks and gradual lengthening of time between visits after that
- 24. • Current recommendations suggest that the energy intake should be approximately 500 calories less than energy output in a weight loss program. • A calorie deficit of 500 - 1000 cal/d produces a weight loss of 1 to 2 lb/wk (0.45 to 0.91 kg/wk).
- 25. Weight-loss associated morbidity • Although obesity in itself is associated with increased morbidity and mortality, massive, poorly monitored weight loss and/or weight cycling can have equally dire consequences. • Among the important potential complications to watch out for in the setting of weight loss are the following: • Cardiac arrhythmias • Electrolyte derangements - Hypokalemia is the most important of these • Hyperuricemia • Psychological sequelae - Including depression and the development of eating disorders (particularly binge-eating disorders) • Cholelithiasis • The use of severe calorie-restricted diets (800 kcal/day) has been responsible for many deaths. The most common cause of death is sudden cardiac death as a result of ventricular arrhythmias or dysrhythmias.
- 26. Weight Loss Program Essential Components (1) Nutritionally balanced diet, • Conventional diets can be broadly classified into 2 categories: • balanced, low-calorie diets and reduced portion sizes • diets with different macronutrient compositions. which include: • Low-fat diets - Eg, the Ornish diet • Low-carbohydrate diets - Eg, the Atkins diet • Midlevel diets - Eg, the Zone diet, in which the 3 major macronutrients (fat, carbohydrate, protein) are eaten in similar proportions of 30-40% (2) Aerobic and strengthening exercise, • Aerobic isotonic exercise is of the greatest value for persons who are obese. The ultimate minimum goal should be to achieve 30-60 minutes of continuous aerobic exercise 5-7 times per week. Increased physical activity and exercise 300 min/week is associated with significant weight reduction and longer maintenance of the weight loss. • Patients should engage in moderate to vigorous physical activity for at least 30 min/d, 5 d/wk, both to maintain weight loss and for the independent health benefits of exercising • Anaerobic isometric exercise, including resistance training, can be cautiously added as an adjunct after the aerobic goal described above is achieved. Resistance training is valuable in minimizing muscle mass loss and is particularly beneficial in patients with diabetes, as it increases glucose uptake by muscles. (3) Behavioral therapy • The purpose of behavior modification therapy is to help patients identify and modify eating and physical activity habits that contribute to obesity.
- 27. Weight losing advices • Have 6-12 months plan • Eat 1/3 less than usual meal • Substitute vegetables & fruits instead of cake, biscuit as snacks • Go for natural foods, avoid junk food • Avoid alcohol, sugary soft drinks & high caloric fruit juices • Use high fiber foods • Drink copious water, at least 2 L • Avoid non hungry eating • Eat slowly
- 28. Q: A behavioral modification plan that could cause more harm than good would include: A. Setting a rule to eat only while sitting down B. Rewarding yourself with food for a job well done. C. Avoiding social gathering when fat food is served. D. Eating only when you are hungry.
- 29. Pharmacotherapy Pharmacologic therapy may be offered to those with a • BMI greater than 30 • Waist circumference ≥35 (women) or ≥40 (men) • BMI of 27 to 30 with comorbid conditions. • Only orlistat is approved for long-term use of up to 2 years. • With the exception of orlistat, which inhibits the absorption of dietary fat, all medications approved for obesity act as anorexiants e.g. phentermine, which is indicated for short term use (a few weeks).
- 30. Pharmacotherapy • All are indicated as adjuncts to caloric restriction, increased physical activity, and behavior modification. • Response to therapy should be evaluated by week 12. • If a patient has not lost at least 5% of baseline body weight, stimulants should be discontinued, as it is unlikely that the patient will achieve and sustain clinically meaningful weight loss with continued treatment. • Currently, the 3 major groups of drugs used to manage obesity are as follows: • Centrally acting medications that impair dietary intake • Medications that act peripherally to impair dietary absorption • Medications that increase energy expenditure
- 31. • Metformin and exenatide, both approved for type 2 diabetes mellitus, may be a useful for weight loss in patients with comorbid obesity. • Metformin can also help with weight loss in patients with polycystic ovary syndrome.
- 32. DRUG NAME MECHANISM OF ACTION Phendimetrazine Sympathomimetic (increased norepinephrine release) Numerous drug interactions; stimulant side effects include insomnia, agitation, tachycardia, hypertension; additive effects with other stimulants (caffeine, cold medications, etc); can be addicting; avoid with monoamine oxidase inhibitors; all indicated for short-term (generally interpreted as up to 12 weeks) use only Diethylpropion Phentermine Orlistat Selective inhibitor of Pancreatic lipase, results in reduced intestinal digestion of fat and increase fecal fat excretion. GI side effects common: diarrhea, bloating, gas, oily stools; must follow low-fat diet to reduce side effects; indicated for short- or long-term use
- 34. Anti-obesity Medications • Orlistat: Its blocks the action of pancreatic lipase, reducing triglyceride digestion and, thus, absorption. The drug may reduce absorption of some fat-soluble vitamins (A, D, E, K) and beta-carotene, as well as absorption of some medications. Adverse effects include flatulence, fatty/oily stool, increased defecation, and fecal incontinence. • Lorcaserin: On February 13, 2020, the FDA requested that lorcaserin be voluntarily withdrawn from the market by its manufacturer owing to a clinical trial indicating that the drug carries an increased cancer risk. It is thought to decrease food consumption and promote satiety by selectively activating 5-HT2C receptors on anorexigenic pro-opiomelanocortin neurons in the hypothalamus. • Liraglutide (Saxenda): is a glucagonlike peptide-1 (GLP-1) analog. GLP-1 is a physiological regulator of appetite and calorie intake, and the GLP-1 receptor is present in several areas of the brain involved in appetite regulation.
- 35. Anti-obesity Medications • Phentermine and topiramate • Bupropion and naltrexone: This combination is thought to cause a reduction in appetite and increase in energy expenditure by increasing the activity of pro-opiomelanocortin (POMC) neurons. Bupropion increases dopamine activity in the brain, which appears to lead to a reduction in appetite and increase in energy expenditure by increasing activity of POMC neurons. Naltrexone blocks opioid receptors on the POMC neurons, preventing feedback inhibition of these neurons and further increasing POMC activity.
- 36. Bariatric Surgery • Patients with a BMI greater than 40 who have failed diet and exercise (with or without drug therapy), OR • Greater than 35 with comorbid conditions. • Roux-en-Y gastric bypass (causes malabsorption) • Lap banding (complications of the banding procedure are less common and less severe than in gastric bypass, but the weight loss may also be less).
- 38. Q: The maximum weight loss per week is: • 0.45 - 0.9 kg • 1.25 - 2.25 kg • 2.25 - 3 • 3.5 - 4.5 kg
- 39. Summary • Obesity is a risk factor for many chronic diseases • BMI is good indicator used to assess obesity • Abdominal obesity can be assessed by measuring waist circumference & W/H ratio • Obesity can be managed by changing dietary habits and life style modification