ObesityObesity

Definition of obesityDefinition of obesity

Obesity is defined by a body-mass Obesity is defined by a body-mass index (weight divided by square of index (weight divided by square of the height) of 30 kg the height) of 30 kg m–2m–2 or greater or greater..

**BMI is the weight in kilograms BMI is the weight in kilograms divided by the square of the height divided by the square of the height in metresin metres..

classification of overweightclassification of overweightBMI* (kg m–2) WHO classification BMI* (kg m–2) WHO classification Popular descriptionPopular description

<<18.518.5 Underweight ThinUnderweight Thin18.518.5––24.924.9‘ — ‘ — Healthy’, ‘normal’, Healthy’, ‘normal’,

‘acceptable‘acceptable’’25.025.0––29.929.9 Grade 1 overweight OverweightGrade 1 overweight Overweight

30.030.0––39.939.9 Grade 2 overweight ObesityGrade 2 overweight Obesity≥≥40.040.0 Grade 3 overweight Morbid obesityGrade 3 overweight Morbid obesity

Factors influencing obesityFactors influencing obesity

11--GeneticsGenetics

22--Environmental factors It seems Environmental factors It seems likely that environmental likely that environmental influences actinfluences act

through increasing energy intake through increasing energy intake and/or decreasing energy and/or decreasing energy expenditureexpenditure

33--Energy expenditureEnergy expenditure. The most . The most variable component of energy variable component of energy expenditure is hysical activity, expenditure is hysical activity, representing 20–50% of total energy representing 20–50% of total energy expenditureexpenditure..

44 - -Energy intakeEnergy intake There is some There is some evidence that high-fat diets are evidence that high-fat diets are associated with an increased associated with an increased risk of obesity within populationsrisk of obesity within populations

55 - -CultureCulture 66 - -Fetal nutritionFetal nutrition. Evidence . Evidence

indicates that undernutrition of the indicates that undernutrition of the fetus during intrauterine fetus during intrauterine development may determine the development may determine the later onset of obesitylater onset of obesity

Effect of obesity on the bodyEffect of obesity on the body

11 - -Obesity leads to type 2 Obesity leads to type 2 diabetes mellitusdiabetes mellitus

22--The effects of obesity The effects of obesity Cardiovascular function The Cardiovascular function The increase in circulatory preload increase in circulatory preload and afterload lead to left and afterload lead to left ventricular (LV) dilatation and ventricular (LV) dilatation and hypertrophyhypertrophy . .

33-- Sleep-breathing abnormalities in obesitySleep-breathing abnormalities in obesityDuring sleep, there is alveolar During sleep, there is alveolar hypoventilation and transient episodes of hypoventilation and transient episodes of apnea that are accompanied by a fall in apnea that are accompanied by a fall in arterial oxygen saturation (hypoxia) and a arterial oxygen saturation (hypoxia) and a rise in arterial carbon dioxide rise in arterial carbon dioxide (hypercapnia). In some individuals, these (hypercapnia). In some individuals, these factors lead to daytime sleepiness factors lead to daytime sleepiness (hypersomnolence) with persistent hypoxia (hypersomnolence) with persistent hypoxia and hypercapnia accompanied by the and hypercapnia accompanied by the development ofdevelopment ofpulmonary hypertension, heart failure and pulmonary hypertension, heart failure and eventually, respiratory failureeventually, respiratory failure..

44 - -Cerebrovascular diseaseCerebrovascular disease

Obesity is linked to an increased risk Obesity is linked to an increased risk of stroke in both men and womenof stroke in both men and women

55 - -Gastrointestinal system Gastrointestinal system gastroesophageal refluxgastroesophageal reflux

--Hepatobiliary diseaseHepatobiliary disease

Obesity is associated with cholelithiasis. Obesity is associated with cholelithiasis. In the Nurses’ Health Study, women In the Nurses’ Health Study, women with BMI <24 kg/m2 had an incidence with BMI <24 kg/m2 had an incidence of symptomatic gallstones of of symptomatic gallstones of approximately 250 per 100 000 approximately 250 per 100 000 person-years of follow-up. Women person-years of follow-up. Women with BMI >45 kg/m2 had a seven-fold with BMI >45 kg/m2 had a seven-fold increase in risk for gallstonesincrease in risk for gallstones

- - OsteoarthritisOsteoarthritis

--CancerCancer

----Psychosocial functionPsychosocial function

--Gynaecological and obstetric Gynaecological and obstetric complicationscomplications

--Surgical and anesthetic Surgical and anesthetic complicationscomplications

Management of obesityManagement of obesity

11--DietingDieting

22--ExerciseExercise

33--Weight loss programsWeight loss programs

44-- MedicationMedication

55--SurgerySurgery