1. khalilzadeh_s

2. Obesity is a chronic disease that is causally related to serious medical illnesses Body mass index (BMI) is calculated by dividing a person's weight (in kilograms) by height (in meters squared); alternatively, the weight (in pounds) multiplied by 704 and divided by height (in inches squared) may be used. There is a curvilinear relation between BMI and percent body fat mass. [3] However, the current practical definition of obesity is based on the relationship between BMI and health outcome rather than BMI and body composition.

3. Weight ClassificationObesity ClassBMI (kg/m 2 )Risk of Disease Underweight <18.5Increased Normal 18.5-24.9Normal Overweight 25.0-29.9Increased ObesityI30.0-34.9High II35.0-39.9Very high Extreme ObesityIII≥40.0Extremely high Weight Classification by Body Mass Index (BMI.)

4. Physiology of Energy Homeostasis  Energy homeostasis, which includes all processes that aim to maintain energy balance, requires complex molecular and physiologic processes and constant communication within and among adipose tissue, skeletal muscle, liver, pancreas, and the central nervous system The hypothalamus functions as the main cerebral center in which these signals converge. [

5. 1.balanced interaction between two sets of neurons occurs within the arcuate nucleus of the hypothalamus. Activation of neurons secreting neuropeptide Y (NPY) and agouti-related protein (AgRP) promotes food intake, whereas that of neurons secreting pro- opiomelanocortin (POMC) and cocaine- and amphetamine- regulated transcript (CART) has an anorexigenic effect

6. Orexigenic neuropeptide Y and agouti-related protein endocannabinoid system ghrelin, Anorexic pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) Glucagon-like peptide 1 (GLP1) cholecystokinin (CCK). Leptin

7. Obesity is caused by an excessive intake of calories in relation to energy expenditure over a long period of time Total daily energy expenditure (TEE) comprises resting energy expenditure (REE), which accounts for approximately 70% of TEE; energy expended in physical activity (approximately 20% of TEE); and the thermic effect of food (TEF), which accounts for approximately 10% of TEE. REE represents the energy expended for normal cellular and organ function under postabsorptive resting conditions. Energy expended in physical activity includes the energy costs of both volitional activity, such as exercise, and nonvolitional activity, such as spontaneous muscle contractions, maintaining posture, and fidgeting. The TEF represents the energy expended in digestion, absorption, and sympathetic nervous system activation after ingestion of a meal