GB 14. Obesity and Eating Disorders Flashcards
What is the definition of fat dependent on?
- sex
- age
- life style
What is the most important measure of obesity? What are the different methods used to calculate percentage body fat?
Percentage Body Fat
- skinfold measurements
- electrical impedance measurements
- calculated from average density (requires a pool)
- dual energy X-ray absorption (most accurate)
What is the most accurate way to calculate percentage body fat?
Body Mass Index (BMI)
- kg/m2
How can the view on fatness change from culture to culture?
- some cultures consider fat to be attractive
- some cultures consider slim to be attractive
- changes with time!
What is Mauritania?
- fat is seen as attractive
- girls are force fed to make them fat
What is the BMI value for those underweight?
below 18.5
What is the BMI value for those of normal weight?
18.5 to 24.9
What is the BMI value for pre-obesity?
25.0 to 29.9
Why is waist-hip ratio important?
it is a better discriminator for ideal weight
side note on slide 18: strong evidence of J or U shaped curve mortality and BMI
What is MHO?
Metabolically Healthy Obese
- preserved insulin sensitivity
- lower inflammatory activity
- normal liver function
- younger
- physically active
- good nutritional status
What is MUO?
Metabolically Unhealthy Obese:
- insulin resistance
- hypertension
- altered liver function
- older
- fat accumulation
- sedentary
- poor nutritional status
What is the obesity paradox?
It is a medical hypothesis which holds that obesity (and high cholesterol) may counterintuitively be protective and associated with greater survival in certain groups of people (e.g elderly individuals)
Why is there limitations to BMI?
BMI is developed as a population-based tool not an individual diagnostic
- individuals with high muscle mass may be affected as well
Explain how all fat is not the same.
[1] abdominal adipose this is strongly associated with increased mortality
- abdominal fat is associated with visceral fat (central obesity)
- visceral fat is hormonally active
—— adipokines
—— associated with type II diabetes
[2] hip adiposity is not as bad as abdominal fat
What is visceral fat?
It is hormonally active
- adipokines
- associated with type II diabetes
What are the AHA Guidelines for: Underweight Normal Overweight Obesity (Type I and Type II) Extreme Obesity
Underweight: less than 18.5 Normal: 18.5 to 24.9 Overweight: 25 to 29.9 Obesity: 30 to 34.9 (type I) 35 to 39.9 (type II) Extreme Obesity: greater than 40
What are the causes of obesity?
- primarily due to energy imbalance (energy consumption exceeds energy expenditure)
- energy expenditure depends on:
—— basal metabolic rate
—— level of activity - obesity is a disease of over-eating, not metabolism!
What is Ghrelin?
- hunger hormone triggers the desire to eat
- produced in stomach
- ghrelin/growth hormone secretagogue receptor (GHS-R)
- arcuate nucleus
- activates dopamine pathways triggering reward signal
What is leptin?
- satiety hormone stops further eating
- produced by adipose tissue
- increases secretion pro-opiomelanocortin (POMC)
- precursor for a- and b- melanocyte stimulating hormone
- arcuate nucleus
What are the treatments for obesity?
[1] Behavioural Therapy
[2] Dietary Therapy
[3] Pharmacological Therapy
[4] Surgery
What can lead to weight loss?
- reduce intake of energy
- increase energy consumption
- for average adult:
—— staying in bed (1150 kcal)
—— exercise (4x to 8x)