Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Clinical Nutrition > Metabolism of Weight loss and Adaptations > Flashcards

Metabolism of Weight loss and Adaptations Flashcards

1
Q

at rest which organs have the greatest % energy expenditure

A

brain, liver, skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

fuels in a 75-kg man

A

adipose - 110,000
protein - 25,000 other + 25,000 muscle

carb- 2,000 muscle glycogen
liver glycogen - 400
free glucose - 80

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

weight of using 100 kcal of glycogen, protein and adipose tissue (explain the differences)

A

The main principle here is that glycogen is hydrophilic and therefore when 100kcal glycogen is spent, water is also lost ( so on the scale it will look like 100g is lost) whereas when 100kcal of adipose is used, 10 g will be lost- bc no water weight is lost (where does the water go?)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the 3 phases of blood glucose curve

A

uptake slope (1 hour), decay slope (1.5-3 hours) and steady phase (34 hours after)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

lower insulin: glucagon is going to trigger?

A

steady phase in which increased glycogenolysis and gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why do TG take longer to increase than glucose after a mixed meal ?

A

must be packed into CM, enter lymphatic system, give off TG into tissues, go to liver, repacked as VLDL- whereas glucose absorbed right into bloodstream from the gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

difference between FFA and TG response after a meal

A

TG slowly increase from the meal, FFA raise from lipolysis during higher glucagon and less insulin, when FA need to be used for gluconeogenesis ( they are NOT from meal )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why does glycerol decrease after a meal

A

bc lipolysis is decreased in response to insulin

  • same kinda thing as FFA, we do not need gluconeogenesis with high insulin
  • we see a slow increase after glycogen in excreted and insulin is lowered which will induce lipolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what happens to total amino acids after a meal

A

they are going to increase as they get transported into the blood, then insulin has a profound impact on the uptake of AA into tissues which will prompt protein synthesis, later once glucagon is secreted, and insulin is lowered, the proteolysis is no lower restricted and so AA would increase later on - gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what happens to urea nitrogen after a meal

A

it will decrease, this is because the increase in amino acids result in protein synthesis and not the breakdown. may not nessasarily be a positive N balance bu the influx of aa will at least create a zero N balance
- later we see it may increase as proteolysis is induced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why do pre-diabetic/insulin resistance lead to hypoglycaemia

A

insulin resistance means insulin is still excreted in large amounts, just the cells are unresponsive. Therefore there is dysregulation of the negative feedback mechanisms, where the excess insulin secretion will promote smaller amounts of glucagon. so now less gluconeogenesis, glycogenolysis and lower blood glucose levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

is there such thing as glycogen resistance

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what dictates energy storage

A

insulin: glucagon storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what causes fat storage

A

excess carbs + excess fat ( excess energy causes fat storage - not necessarily a function of high GI foods alone

  • what about excess protein ??
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the goals of adapting to fasting?

A
  • reduce LBM breakdown ( spare protien)
  • meet energy needs (REE will lower, become more efficient, less movement)
  • glucose requirements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

alanine cycle

A

pyruvate in muscle turns to alanine, gets transported in blood to liver, turned back to pyruvate–> gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

early fasting

A

2000kcal/24h

  • gluconeogenesis
  • glycogenolysis
  • lipolyis (constant rate )
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

prolonged fasting

A

decrease EE by 500kcal
- 1500kcal/24 h

  • liplysis (constant rate)
  • no glycogen
  • sparing effect - less gluconeogeneis from proteins - ketone bodies switch to being main fuel
  • cori/alanine continues at the same rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

prolonged fasting

A

decrease EE by 500kcal
- 1500kcal/24 h

  • lipolysis ( constant rate)
  • no glycogen
  • sparing effect - less glujconeogeneis from proteins - ketone bodies switch to being main fuel
  • cori/alanine continues at the same rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

before ketones can be excreted they ned to be?

A

salted out which involves the loss of NA, K H, orNH4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what cation is preferred for ketone excretion

A

K , which can lead to hypokalemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

pro requirement

A
  1. 0 healthy

1. 0-1.2 for elderly adult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

fluid requirements

A

100 ml/kg 1st 10
50ml/kg 2nd 10
20ml for ever kg after that

ex. 70 kg man
(10 x 100) + (50 x 10) + (20 x 50) = 2500ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

fluid based on energy

A

1ml/kcal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

fluid balance based on urine output

A

urine output + 500mL/d

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

describe the prolonged total fasting weight loss curve

A

rapid weight loss at the beginning bc glycogen and protein stores are being used
- over time switch to fat ( no water, so less weight seen) lipolysis at a steady state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

why does urea decrease with prolonged starvation and ammonia increase?

A

more ketone bodies are being excreted in the body , get salted out with ammonia. protein sparing effect, so less catabolism of protein, less proteolysis which means less urea

  • overall less g of nitrogen are excreted bc less overall breakdown and intake of protein
  • increase in ammonia also from gluconeogenesis in the kidneys
  • glutamine into glucose
28
Q

renal consequences of starving

A
  • need normal kidney function
  • ammonia is toxic so need more water
  • acid/base balance changes in response to starvation need to be controlled by the kidney
29
Q

describe the main idea behind the N intake, EE and N balance graph

A

This graph shows that for someone who EI=EE (1.0), as N intake increases, N retention increase and you will reach zero, you can see that it is possible to go into a positive nitrogen balance for a short time but it will eventually balance out to zero as body adjusts. we see that when someone is not meeting energy needs it takes longer for them to reach zero ( if ever) bc so much protein catabolism is taking place ( so much N excretion). in the same sense someone eating above E requirement, can reach a N balance faster ( with less pro intake) so a positive N balance can be seen even with low intake ( less excretion )

30
Q

why in graph with reduction diets was N balance initially negative ?

A

on a energy restriction diet, the body was needing to use some protein so excreting a lot of N , and are not able to reach zero until body adjusts ( relies less on protein )

31
Q

describe Forbes equation

A

relationship between the amount of body fat and the loss of LBM during dieting

  • with higher body fat initially, we see less LBM loss: total weight
  • whereas, if low body fat, will have more LBM loss
32
Q

Forbes predictions 1:

A

during fast, obese individuals will lose less nitrogen ( hence less LBM) than thin ppl

33
Q

Forbes prediction 2:

A

the fatter the subject the less LBM to Toal weight loss

34
Q

what happens to the cardiovascular system with severe weight loss?

A 
less cardio output, HR, BP
increased tachycardia ( fast heart beat to compensate for low BP and low BV)
35
Q

what happens to the immune system with severe weight loss?

A

less T-cell function/lympocytes

less cytokines

36
Q

what happens to the renal system with severe weight loss?

A

acid/base stress on the kidneys

37
Q

what happens to the GI system with severe weight loss?

A

less lipid absorption- ste-at-orr-hea (fatty stools)

38
Q

what happens to the electrolytes with severe weight loss?

A

potassium losses - hypokalemia

39
Q

why does steatorrhea occur during starvation?

A

decrease in villous SA due to atrophy ( gradually decline in effectiveness or vigor due to underuse or neglect ) - bc eating less, using system less - so less lipid absorption

40
Q

why is there potassium loss with severe weight loss?

A

potassium is the main buffering agents during the excretion of ketoacids
- this casues hypokalemia

41
Q

why would we never advise someone with impaired kidney function a severe weight loss diet

A

acid/base balance changes in response to starvation need to be controlled by the kidney
if not properly functioning - build up of keto acids, not properly excreted - toxic
acid/base stress on the kidneys

42
Q

refeeding syndrome

A

metabolic complication associated with nutritional repletion

43
Q

cause of referring syndrome

A

shift back to glucose instead of ketoacids

44
Q

what does the shift back to glucose cause

A

rapid fluxes of insulin
rapid shift of electrolytes and anions and cations into intracellular space ( think sodium glucose linked transporters that are needed for uptake of glucose into the cells) so when lots of insulin - lots of glucose moving into the cell - lots of anions and cations moving into the cell
- this casues sodium and water retention ( anions moving into cell- water following )

45
Q

which anion/cation is the biggest issue during the referring syndrome?

A

The hallmark biochemical feature of refeeding syndrome is hypophosphatemia, also referred to as refeeding hypophosphatemia (RH). … The combination of cellular uptake of phosphorus together with depletion of total body stores during starvation causes extracellular hypophosphatemia.

46
Q

symptoms of referring syndrome ( mostly due to hypophosphatemia )

A

fatigue, weakness, arrhythmia, hemolysis, edema, dizziness, lethargy

47
Q

how fast is onset of referring syndrome

A

fast ( first day of repletion )

48
Q

what changes physiologically during repletion

A

ECF expansion - deem from increased Na intake and electrolyte imbalances ( this is why want to limit water and salt intake during referring )

49
Q

ECF expansion

A

The sodium retention and extracellular fluid expansion together with thiamine deficiency can lead to congestive cardiac failure. excess carbs lead to the retention of sodium and water

50
Q

glycogen synthesis during refeeding

A

may lower serum Po4 and K concentration

51
Q

increased REE during refeeding

A

due to the reversal of starvation and LBM rebuilding and thermogenic effects of metabolizing food

52
Q

physiological changes during repletion

A
  1. glycogen synth
  2. insuring secretion
  3. ECF expansion
  4. increased REE
53
Q

steps in refeeding

A
  • normalize fluid balance and electrolytes - PO4, K and Mg with supplements ( seperatee from food)
  • limit sodium and water intake
  • mixed diet- aim for 100-150g glucose to stop LB breakdown but start with 25% dose
  • thaimine supplement
    protein at 1.5-2 ( but start at 20g/day)
  • monster
54
Q

why is thiamine so important in refeeding syndrome

A

cofactor for many anabolism mechanism - for production of ATP

55
Q

PRO for refeeding

A

start with 20g/day but gradually increase to 1.5-2 g/kg/d

56
Q

glucose for refeeding

A

aim for 150-200g/d but start with 25% dose

57
Q

important supplements during refeeding

A

K, PO4, Mg, thiamine

58
Q

physiological changes after diet induced weight loss that lead to increased energy storage

A

lowered FA oxidation, EE, thyroid hormones, increased cortisol

59
Q

physiological changes after diet induced weight loss that lead to increased food intake

A

low leptin, PYY, amylin, insulin and raised gherkin and altered neural activity

60
Q

how much does REE decrease per kg lost

A

15%

61
Q

what lead to a decrease in EE during weight loss

A

15% REE
less PA
decrease in TEF

62
Q

PYY _____ after weight loss

A

decreased ( it is an anorexigenic hormone that decreases hunger)

63
Q

what did high fat/low carb diet resemble

A

metabolically similar to “fasting state”

64
Q

describe high Fat vs high carb diet results

A

more severe weight loss initially with high fat (more water loss?), but net result was only a slight weight difference ( < 1kg)

65
Q

effect of insulin on low fat vs low carb?

A

no effect- didn’t prevent baseline insulin

66
Q

short term effects of keto

A

halitosis, muscle cramps, headache, weakness, rash,

67
Q

long term effects of keto

A 
ketoacidosis ( if illness also) 
elevated LDL
renal stones
thiamine def
carotene def
water sol vitamin def

Clinical Nutrition (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions