In 1997, the International Obesity Task Force,10 convened by the World Health Organization (WHO), recommended a standard classification of adult overweight and obesity
Paleolithic: the first period in the development of human technology of the Stone Age
Obesity is a complex, multifactorial condition in which excess body fat may put a person at health risk. According to the U.S. surgeon general, approximately 25 percent of American adults are completely sedentary, and more than 60 percent are not regularly active at the recommended level of 30 minutes per day.5 About 14 percent of young people between 12 and 21 years of age report no recent physical activity. Nearly one half of young persons between these ages are not vigorously active. An estimated 300,000 preventable deaths occur each year in the United States because of unhealthy diet and physical inactivity,6 which are known contributors to obesity.
the past 20 years there has been a dramatic increase in obesity in the United States. In 2006, only four states had a prevalence of obesity less than 20%. Twenty-two states had a prevalence equal or greater than 25%; two of these states (Mississippi and West Virginia) had a prevalence of obesity equal to or greater than 30%.
Presently, there is no precise clinical definition of obesity based on the degree of excess body fat that places an individual at increased health risk. General consensus exists for an indirect measure of body fatness, called the weight-for-height index or body mass index (BMI). The BMI is an easily obtained and reliable measurement for overweight and obesity and is defined as a person's weight (in kilograms) divided by the square of the person's height (in meters) Other Measurements Waist Circumference >35 inches in women or 40 inches in men indicates hazardous fat distribution Waist/Hip Ratios >0.8 indicates hazardous fat distribution
The search for genetic factors involved in obesity should not obscure the truth that the environmental factors probably more important.
In most cases, however, the increasing prevalence of overweight and obesity reflects changes in society and behaviors over the past 20 to 30 years. Lifestyle patterns are influenced by an overabundance of energy-dense food choices and decreased opportunities and motivation for physical activity. Loss of ovarian function results in: Reduced resting metabolic rate Reduced muscle mass Increased fat mass Increased accumulation of abdominal adipose tissue
Excess body fat results from an imbalance of energy intake and energy expenditure (total energy expenditure includes energy expended at rest, in physical activity and for metabolism)
Leptin signals the brain about the quantity of stored fat. Modulates food intake.
Leptin, a hormone secreted by fat cells that was discovered in 1994, was found to not only control food intake, but also to impact other functions that are affected by energy balance which could relate to obesity. High leptin levels trigger growth and readiness for reproduction. Research has shown that overweight individuals have high concentrations of leptin in the blood, indicating that these individuals do not respond to leptin by reducing food intake. Furthermore, endocrine research has found that obese patients respond poorly to leptin, suggesting the presence of leptin resistance.
Waist circumference measurements greater than 40 inches (102 cm) in men and 35 inches (89 cm) in women also indicate an increased risk of obesity-related comorbidities.
The recent increases in the prevalence of overweight and obesity are reflected across all ages, racial and ethnic groups, and education levels in the U.S. In reviewing the following three charts, for instance, one can see that the “average” American categorized under obesity is aged 50-59, Black/non-Hispanic with less than a high school diploma
A 100 kg woman is at the same risk for coronary artery heart disease as a woman who smokes 1 ppd 40% of coronary artery disease is attributed to being overweight
Waist circumference should be measured at a level midway between the lower rib margin and iliac crest with the tape all around the body in horizontal position
No. 1 = Germany (58% of the population) No. 2 = United States of Amerika (57%) No. 3 = Australia (56%)
The Roux-en-Y gastric bypass procedure involves creating a stomach pouch out of a small portion of the stomach and attaching it directly to the small intestine, bypassing a large part of the stomach and duodenum. Not only is the stomach pouch too small to hold large amounts of food, but by skipping the duodenum, fat absorption is substantially reduced.
Definition• A BMI of 25.0 to 29.9 kg per m2 is defined as overweight; a BMI of 30.0 kg per m2 or more is defined as obesity. 2
Historical PerspectivePaleolithic Era > 25,000 years ago 3
Obesity - How Big A Problem…• 1.7 billion worldwide are overweight or obese• The US has the highest percentage of obese people.• By 2006, only four states had a prevalence of obesity less than 20%. And the numbers are growing… 4
Epidemiology of Obesity• 31.3% of U.S. males• 34.7% of U.S. females• 30% increase in the last 10 years• Health care costs - >$100 billion/year• Results in 300,000 preventable deaths each year in the U.S. 5
Obesity and Life Expectancy• If current rates of obesity are left unchecked, the current generation of American children will be the first in two centuries to have a shorter life expectancy than their parents.Olshansky SJ, et al. A Potential Decline in Life Expectancyin the United States in the 21st Century. NEJM, 352(11):1138- 1145, 2005 6
Classification of Overweight and Obesity• BMI Classification <18.5 Underweight – 18.5-24.9 Normal weight – 25-29.9 Overweight – 30-34.9 Obesity Class I – 35-39.9 Obesity Class II – 40-49.9 Obesity Class III – 50 and aboveSuper Obesity 9
Nutrient and Energy Model of ObesityObesity results from increased intake of energy or decreased expenditure of energy, as required by the first law of thermodynamics. Energy Energy Intake Expenditure Adipose tissue 13
Why is it so hard to lose weight? External factors Brain Emotions Food characteristics Central Signals Lifestyle behaviors Stimulate Inibit Environmental cues NPY Orexin-A α-MSH CART AGRP dynorphin CRH/UCN NE galanin GLP-I 5-HTPeripheral signals Peripheral organs Glucose Gastrointestinal CCK, GLP-1, tract− Apo-A-IV Vagal afferents Food Insulin Intake+ Ghrelin Adipose− Leptin tissue+ Cortisol Adrenal glands 14
Leptin• Protein hormone produced by fat cells.• Experiment: Leptin deficient mice: Hyperphasic Insulin resistant Infertile Leptin administration reversed all the symptoms. 15
Medical Complications of ObesityPulmonary diseaseabnormal functionobstructive sleep apneahypoventilation syndrome Stroke Cataracts CHDNonalcoholic fatty liver disease Diabetessteatosis Dyslipidemiasteatohepatitis Hypertensioncirrhosis Severe pancreatitis Gall bladder disease Cancer Gynecologic abnormalities breast, uterus, cervix abnormal menses colon, esophagus, pancreas kidney, prostate infertility Osteoarthritis PCOS Phlebitis venous stasis Gout 16
Consequences of ObesityHippocratesrecognized that :“sudden death is more common in those who are naturally fat than in lean.” 18
Treating Obesity• Measure height and weight (BMI)• Calculate waist circumference• Assess comorbidities• What labs does the patient need?• Is the patient ready and motivated enough to loose weight?• Which diet should you recommend?• Discuss a physical activity goal 19
Weight Loss Strategies• Diet therapy• Increased Physical Activity• Pharmacotherapy• Behavioral Therapy• Surgery• Any combination of the above 20
Rate Of Weight Loss• A realistic goal is from 5% to 15% from baseline in 6 months of obesity treatment.• Weight should be lost at the rate of 1-2 lbs per week, based on the caloric deficit between 500-1000 Kcal/day. 21
Dieting• Dieting is highly ineffective - 95% long term failure rate• Often results in higher weight than before the diet 23
Principles Of Dieting• Women should consume atleast 1200 kcal/day, men 1500 kcal/day.• Select a diet that has: >75g/day proteins (15% of total calories) > 55% total calories from carbs▪ Fat should contribute 30% or less of total caloriesAtleast 3 meals/day.High fiber (20-30g/day), fruits and vegetables.Supplement the diet with multivitamis and minerals.Avoid sugar containing beverages and fat spreads. 24
What about all the diets that are out there?• Weight Watchers ($13 registration fee, $15 weekly fee)• Jenny Craig (consultation $200-370, $65 meals/week)• Tops Club ($20/week)• Nutrisystem.com ($50/week)• Atkins Diet 25
MedicationsA) Serotonin Nor-epinephrine Reuptake Inhibitor: reduces food intake. Sibutramine: initial dose 10mg/day, max 20mg/day.B) Orlistat: Lipase inhibitor. Alters metabolism, dec absorption of dietary fat. 120mg PO TID 27
Surgery• Roux-en-Y gastric bypass.• Lap band procedureCriteria: a) BMI > 40 or >35 with 2 comorbidities. b) Failure of non surgical methods c) Presence of 2 or more medical conditions that would benefit with weight loss. 29
Obesity warning on London busesThe United Kingdom Branch of the International Size Acceptance Associationis encouraging the public to contact World Cancer Research Fund UK tovoice their concerns about this discriminating ad campaign. 32