Regulation Of Feeding: Obestiy And Starvation

Question 1

What are the key factors for obesity

Answer 1

• *factors that affect body size and DO account for obesity**
• Diet
• Physical activity
• Behavior
• Environment
• *factors that affect body size but DONT account for obesity**
• Genetics
• Neuroendocrine abnormalities
• Patterns of food

no one can definitively account of the obesity epidemic

Question 2

What are the body factors that account for the total daily energy expenditure (TDEE)?

Answer 2

70% = Basal metabolic rate (BMR)
- accounts for the most

15% = non-exercise activity thermogenesis (NEAT)

10% = Thermic effect of food (TEF)

5% = exercise activity thermogenesis (EAT)

resting energy expenditure = basal metabolic rate

non-resting energy expenditure = NEAT + TEF + EAT

Question 3

What is body weight?

Answer 3

The balance between energy intake and energy expenditure

Question 4

What are sophisticated measures to assess body fat and lean body mass?

Answer 4

Bio electric impedance analysis

“Bod Pod”

DEXA
- gold standard

MRI

CT scans

Question 5

What is BMI?

Answer 5

Measure of body mass adjusted for height and is roughly correlated with body fat

BMI = body weight (kg)/ height (m2)

doesnt work well in Asians (underestimates body fat), athletes (overestimates body fat) and elderly (underestimates body fat)

• **if BMI is greater than 35, location is completely irrelevant.
• before this point, it is important to try and determine are of body fat rather than total***

Question 6

What is the cut off for waist-hip circumference ratio?

Answer 6

WHR > 1.0 = high body fat and greater chance of obesity

• men = > 40 inches
• women > 35 inches

Question 7

How to calculate the amount of kcals required daily for someone to maintain their body weight?

Answer 7

(Weight in lbs) * (16kcal/lb) = x

OR

(Weight in kg) * (35kcal/kg) = x

Question 8

How does Leptin relate to appetite?

Answer 8

Made in adipose cells and sends to hypothalamus to regulate hunger and food energy use

• high levels = inhibits hunger and stimulates satiety
• Low levels = stimulates hunger and inhibits satiety

Question 9

What other factors are known to increase and decrease appetite

Answer 9

Increase

• NPY
• MCH
• AnRP
• orexin
• endocannabinoids

Decrease

• serotonin
• CART
• GLP-1

Question 10

What kind of compensatory mechanisms does the body experiment in forced fasting and over feeding

Answer 10

Forced fasting = naturally lowers metabolic rates and increases appetite

Forced over feeding = naturally increases metabolic rates and decreases appetite

these usually fail though in chronic situations

Question 11

Malnutrition is defined as

Answer 11

Chronic state of inadequate nutrient intake

- is difficult to define though and numerous situations can induce malnutrition

Question 12

Why is edema a challenge in weight measures?

Answer 12

It can mask muscle wasting and weight loss

Low albumin is a result of malnutrition, which in turn results in increased osmotic pressures within the body tissues

Question 13

What are the two most common world-wide malnutrition disorders

Answer 13

1) Kwashiorkor: starvation in children usually seen after weening (deficiency in proteins)
- prominent abdominal edema
- refeeding makes the child look worse but are actually getting better
- has corse hair that often falls out
- high risk of cachexia that develops fast (weeks)

2) Marasmus: prolonged starvation with gradual wasting (deficiency in everything)
- very prominent bones apperence
- decreased resting metabolic rates
- Bradycardia
- responds well to nutrient feeding treatment (unless they are In cachexia)
- low risk of cachexia and takes a while to get to (years)

Question 14

The diagnosis of malnutrition requires what based off GLIM criteria?

Answer 14

1 phenotypic criteria And 1 etiologies criteria

Question 15

What is cachexia

Answer 15

A state of extreme muscle wasting and weight loss
- very common in chronic conditions especially cancer

Challenging to treat since it doesnt respond to refeeding treatments

Question 16

Hypometabolism

Answer 16

Normal adaption to starvation

• body conserves mass by reducing metabolic rates
• also retains proteins and prevents use as energy
• Fat becomes the primary source of energy
• lowers metabolic rates to roughly 20-25 kcal/kg*

Question 17

Hypermetabolism

Answer 17

A maladaptive response to physiological stress where energy demands are increased

• body cant use fat well for whatever reason (usually physiological stress)
• uses proteins as primary source
• almost always leads to cachexia

increases metabolic rates to roughly 35-40 kcal/kg

Question 18

How does RMR relate to presence of physiological stress?

Answer 18

It increases almost always

highest in major burns or severe infections

Question 19

Protein catabolism rate equation

Answer 19

(24-hr Urinary urea nitrogen (UNN) + 4) * (6) = x

Question 20

What is the daily dietary protein requirements?

Answer 20

Minimum = 0.65 g/kg body weight

Recommended = 0.80 g/kg body weight

Protein catabolic patients (cachexia) = 1.5 g/kg body weight

Question 21

Refeeding syndrome

Answer 21

A life-threatening complication of feeding a malnutrition patient to quickly
- most likely to occur within the first 24-48hrs

Patients are currently in hypometabolic and fat catabolism
- forces a quick shift to carbohydrate metabolism and mass insulin release

Mass insulin release results in Hypo:

• kalemia
• phosphatemia
• magnesemia
• calcemia

Symptoms:
- weakness/ muscle paralysis/ cardiac output decreased, respiratory failure

Question 22

How to prevent refeeding syndrome

Answer 22

depends how long the bowel has not been used

1) <2weeks of bowel rest
- use clear liquids first
- resume full diet within several days

2) >3weeks of bowel rest
- start refeeding slowly, skip liquids

should watch for fat/lactose/and digestive dysfunctions