Regulation Of Feeding: Obestiy And Starvation Flashcards
What are the key factors for obesity
- *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
What are the body factors that account for the total daily energy expenditure (TDEE)?
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
What is body weight?
The balance between energy intake and energy expenditure
What are sophisticated measures to assess body fat and lean body mass?
Bio electric impedance analysis
“Bod Pod”
DEXA
- gold standard
MRI
CT scans
What is BMI?
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***
What is the cut off for waist-hip circumference ratio?
WHR > 1.0 = high body fat and greater chance of obesity
- men = > 40 inches
- women > 35 inches
How to calculate the amount of kcals required daily for someone to maintain their body weight?
(Weight in lbs) * (16kcal/lb) = x
OR
(Weight in kg) * (35kcal/kg) = x
How does Leptin relate to appetite?
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
What other factors are known to increase and decrease appetite
Increase
- NPY
- MCH
- AnRP
- orexin
- endocannabinoids
Decrease
- serotonin
- CART
- GLP-1
What kind of compensatory mechanisms does the body experiment in forced fasting and over feeding
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
Malnutrition is defined as
Chronic state of inadequate nutrient intake
- is difficult to define though and numerous situations can induce malnutrition
Why is edema a challenge in weight measures?
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
What are the two most common world-wide malnutrition disorders
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)
The diagnosis of malnutrition requires what based off GLIM criteria?
1 phenotypic criteria And 1 etiologies criteria
What is cachexia
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
Hypometabolism
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*
Hypermetabolism
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
How does RMR relate to presence of physiological stress?
It increases almost always
highest in major burns or severe infections
Protein catabolism rate equation
(24-hr Urinary urea nitrogen (UNN) + 4) * (6) = x
What is the daily dietary protein requirements?
Minimum = 0.65 g/kg body weight
Recommended = 0.80 g/kg body weight
Protein catabolic patients (cachexia) = 1.5 g/kg body weight
Refeeding syndrome
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
How to prevent refeeding syndrome
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
