GB 14. Obesity and Eating Disorders Flashcards

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1
Q

What is the definition of fat dependent on?

A
  • sex
  • age
  • life style
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2
Q

What is the most important measure of obesity? What are the different methods used to calculate percentage body fat?

A

Percentage Body Fat

  • skinfold measurements
  • electrical impedance measurements
  • calculated from average density (requires a pool)
  • dual energy X-ray absorption (most accurate)
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3
Q

What is the most accurate way to calculate percentage body fat?

A

Body Mass Index (BMI)

- kg/m2

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4
Q

How can the view on fatness change from culture to culture?

A
  • some cultures consider fat to be attractive
  • some cultures consider slim to be attractive
  • changes with time!
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5
Q

What is Mauritania?

A
  • fat is seen as attractive

- girls are force fed to make them fat

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6
Q

What is the BMI value for those underweight?

A

below 18.5

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7
Q

What is the BMI value for those of normal weight?

A

18.5 to 24.9

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8
Q

What is the BMI value for pre-obesity?

A

25.0 to 29.9

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9
Q

Why is waist-hip ratio important?

A

it is a better discriminator for ideal weight

side note on slide 18: strong evidence of J or U shaped curve mortality and BMI

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10
Q

What is MHO?

A

Metabolically Healthy Obese

  • preserved insulin sensitivity
  • lower inflammatory activity
  • normal liver function
  • younger
  • physically active
  • good nutritional status
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11
Q

What is MUO?

A

Metabolically Unhealthy Obese:

  • insulin resistance
  • hypertension
  • altered liver function
  • older
  • fat accumulation
  • sedentary
  • poor nutritional status
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12
Q

What is the obesity paradox?

A

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)

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13
Q

Why is there limitations to BMI?

A

BMI is developed as a population-based tool not an individual diagnostic
- individuals with high muscle mass may be affected as well

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14
Q

Explain how all fat is not the same.

A

[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

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15
Q

What is visceral fat?

A

It is hormonally active

  • adipokines
  • associated with type II diabetes
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16
Q
What are the AHA Guidelines for:
Underweight
Normal
Overweight
Obesity (Type I and Type II)
Extreme Obesity
A
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
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17
Q

What are the causes of obesity?

A
  • 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!
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18
Q

What is Ghrelin?

A
  • 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
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19
Q

What is leptin?

A
  • satiety hormone stops further eating
  • produced by adipose tissue
  • increases secretion pro-opiomelanocortin (POMC)
  • precursor for a- and b- melanocyte stimulating hormone
  • arcuate nucleus
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20
Q

What are the treatments for obesity?

A

[1] Behavioural Therapy
[2] Dietary Therapy
[3] Pharmacological Therapy
[4] Surgery

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21
Q

What can lead to weight loss?

A
  • reduce intake of energy
  • increase energy consumption
  • for average adult:
    —— staying in bed (1150 kcal)
    —— exercise (4x to 8x)
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22
Q

How many calories does an individual burn for (a) walking and (b) running for 1 mile

A

Walking: burns 124/105 calories (M/F)
Running: burns 88/74 calories (M/F)

23
Q

What is the Sumo Diet?

A
  • very high calorie intake
  • no breakfast
  • large lunch followed by sleep
  • late dinner with lots of beer
24
Q

What are the different diet types?

A
  • balanced low calorie
  • low fat
  • low carbohydrate
  • high protein
  • Mediterranean
  • very low calorie diet
  • fasting
  • fad (e.g. cabbage soup diet
25
Q

What is an Atkins study?

A

Very low in carbohydrate

26
Q

What is a zone study?

A

Low in carbohydrate

27
Q

What is the LEARN study?

A

Lifestyle, Exercise, Attitudes, Relationships and Nutrition: low in fat, high in carbohydrate, based on national guidelines

28
Q

What is an Ornish study?

A

Very high in carbohydrate

29
Q

What are the 3 types of fasting methods?

A

[1] Fasting
- 3.5 days no food

[2] Alternative Day Fasting

  • day 1: 20% of calories (400 to 500 cals)
  • day 2: eat what you like

[3] 5:2 Diet

  • 5 days normal diet
  • 2 non consecutive fasting days (20%)
30
Q

What is a potential benefit to fasting?

A

Fasting diets may prolong life

31
Q

What are the pharmacotherapy guidelines?

A
  • used in patients who fail to lose weight after dieting
  • Orlistat 1st choice (2 to 4 years)
  • meta analysis with 12 month data:
    —— 60% adherence
    —— average weight loss 8.8 kg (placebo is 5.5 kg)
32
Q

What is liposuction? Describe it

A
  • reduces subcutaneous body fat
  • no evidence of clinical benefit
  • does not improve insulin sensitivity
  • does not reduce inflammatory bio markers
33
Q

What is bariatric surgery? What are the 3 different types?

A

Surgical procedures to reduce consumption of food or prevent absorption of food.

[1] Sleeve Gastrectomy
[2] Restrictive
[3] Combination

34
Q

What are the benefits of bariatric surgery?

A
  • recommended for patients with BMI >40
  • average 60% weight in excess of BMI of 25 lost
  • hyperlipidaemia, hypertension and diabetes resolved (70% of cases)
  • increased risk of suicide + self harm
35
Q

What is malnutrition? Explain it a bit. What are some types of malnutrition?

A
  • common in the developing world
  • can be acute or chronic
  • severity in children determined using WHO growth charts

[1] Marasmus
[2] Kwashiorker

36
Q

What is Marasmus? What is it characterized by?

A
  • muscle wasting + depletion of body fat
  • due to inadequate intake of all nutrients and total calories

Characterized by:

  • hunger
  • diminished weight + height for age
  • emaciated
  • bradycardia + hypotension
  • atrophy of muscle and subcutaneous fat
37
Q

What is Kwashiorkor? What is its clinical presentation?

A
  • muscle atrophy
  • normal body fat
  • due to inadequate protein but adequate calories

Clinical Presentation:

  • anorexia
  • normal weight + height for age
  • severe generalized oedema
  • rounded cheeks
  • dry, peeling skin
  • distended abdomen
  • hypopigmented hair
38
Q

What is ReSoMal? What is it used for?

A
  • oral rehydration for malnourished children
  • standard oral rehydration salt with
    —— reduced sodium
    —— increased potassium
  • 70 to 100 mL/kg over 12 hours
39
Q

What is Ready-to-Use Therapeutic Food (RUTF)

A
- ready to use paste
—— peanuts
—— sugar
—— oil
—— powdered milk
—— supplemented with a vitamin and mineral mixture
  • no cooking, long life and high energy
  • mainstay of treatment in community
  • typically 175kcal/kg/day
  • if a child can tolerate 30g RUTF go straight to rehabilation phase
40
Q

What is F-75? What is it used for?

A
  • 75 kcal/100mL
  • used for those who cannot tolerate RUTF
  • infant formula requires potassium supplementation
  • 80 to 100 kcal/kg/day
  • small amounts frequently
41
Q

Explain the treatment - rehabilitation phase.

A
  • switch F-100 (100 kcal/100mL)
    —— commercial tube feed requires potassium supplementation
  • slowly increase to 150 to 220 kcal/kg/day
  • continue until wt/ht z-score > -1
  • begin supplementation with vitamins especially vitamin A, iron + folate
  • switch to RUTF as soon as possible
42
Q

What is anorexia nervosa?

A
  • refusal to maintain body weight above minimum for age + height
  • patients have distorted body image and a fear of gaining weight
43
Q

What is Bulimia Nervosa?

A
  • binge eating
  • compensatory behaviour
    —— typically self-induced vomiting
    —— at least twice per week for 3 months
44
Q

What is binge eating disorder?

A
  • eating large amounts of food in a short period at least 2x per week for 6 months without compensatory behaviour
  • must have at least 3 of the following:
    —— eating large amounts of food when not feeling physically hungry
    —— eating more rapidly than normal
    —— eating until feeling uncomfortably full
    —— eating alone because of embarrassment by the amount of food consumed
    —— feeling disgusted with oneself, depressed or guilty after overeating
    ——
45
Q

What is Cachexia?

A
  • a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass
  • it is characterized by loss of appetite and unintended weight loss and loss of muscle mass
  • it is associated with underlying diseases such as cancer and aging and is associated with significantly increased risk of mortality
46
Q

What is the pathogenesis of anorexia?

A
  • pathogenesis is unclear
  • genetic component
  • associated with:
    —— history of dieting
    —— childhood preoccupation with weight
    —— sports requiring leanness (ballet, gymnastics)
    —— sexual abuse
47
Q

What is the treatment for anorexia?

A
  • nutritional rehabilitation
  • medical monitoring
  • psychotherapy (cognitive behavioural therapy)
48
Q

What is Refeeding Syndrome? What is it characterized by and what are the risk factors?

A

Characterized by:

  • hypophosphatemia (primary cause)
  • hypokalemia
  • hypomagnesemia
  • vitamin (e.g. thiamine) + trace mineral deficiencies
  • volume overload
  • edema

Risk Factors:

  • extent of weight loss
  • rapidity of weight gain
49
Q

What is Feeding Strategy? (‘for anorexia)

A
  • correct electrolyte imbalance
  • begin with calorie intake to reflect energy expenditure
  • increase calories 300 to 400 kcal every 3 to 4 days
  • weight gain should be around 1 kg/week
50
Q

What is the pharmacotherapy for anorexia?

A
  • disappointing
  • meta analysis shows no benefit for anti-depressant (e.g. fluxetine on weight gain)
    —— may help with treating depression
  • small study suggests olanzapine (anti-psychotic) may have benefit
51
Q

What is the pharmacotherapy of bulimia?

A

-fluoxetine (selective serotonin reuptake inhibitor) reduces binge eating
—— reducing vomiting
- second line is sertraline (SSRI)
- 3rd line:
—— tricyclic anti-depressants also effective
—— topiramate (anti-epileptic) may have benefit

52
Q

What is pharmacotherapy of binge eating?

A
  • selective serotonin reuptake inhibitors (e.g. fluoxetine recommended)
  • topiramate (anti-epilipetic) more effective
  • 1st choice is SSRI due to better safety profile
  • topiramate used if needed
53
Q

What is the pharmacotherapy (cancer cachexia)?

A
- use agents known to stimulate appetite 
— glucocorticoids (dexamethasone)
— progesterone analogues (megestrol)
- use strategies known to block satiety
— manage nausea and gastroparesis (failure to empty stomach) 
— eat small frequent meals
- use agents to block cytokines 
— thalidomide (blocks TNF synthesis)