Brainscape's Knowledge GenomeTM

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


See full index

NUTR 344: Clinical Nutrition 1 > 4. Metabolism of Weight Loss and Adaptations > Flashcards

4. Metabolism of Weight Loss and Adaptations Flashcards

1
Q

At rest, which parts of the body are most metabolically active and responsible for the majority of energy expenditure?

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

Which glycogen store in the body is NOT metabolized for energy?

A

Muscle glycogen

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

Out of glycogen, protein tissue, and adipose tissue, which has the least amount of water weight?

A

Adipose tissue

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

Ingested glucose is taken up by the RBCs, muscle, adipocytes, the CNS, and the liver (which is then transported in VLDL to the adipocytes). Which of these (2) requires insulin for the uptake of glucose?

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

Explain what happens during the different phases on the blood glucose curve:

  • uptake slope
  • decay slope
  • steady phase
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens to levels of substances in the bloodstream in response to a meal?

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

Response to meal curves: Glucose Lactate and Pyruvate

A

Response to meal curves: triglycerides, free fatty acids, ketone bodies

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

Response to meal curves: glycerol, alanine, BCAA

A

Response to meal curves: total amino acids, urea nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the differences concerning blood glucose levels after the same glucose challenge between healthy individuals and those with insulin resistance/early diabetes (often associated with those with high BMIs)?

A

Pre-diabetes: higher peak + faster increment, reactive hypoglycemia and a delayed response in glucagon

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

What is the Glycemic Index (GI)?

A

A ranking of foods based on the rate at which different carb sources raise blood glucose levels

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

Montignac and the Zone diets support the theory that a low GI diet favors weight loss. How do they explain this theory?

A

That weight loss is favored by being able to control the amount of carbohydrate and insulin levels in the blood.

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

The basis of low carb and high fat diets is based on…

A

Carbohydrates having the most profound effect on insulin release and therefore are the most likely of the macros to favor energy storage and weight gain.

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

The ratio of _____:______ dictates energy etorage.

A

Insulin:Glucagon

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

What causes changes in blood parameters over a four-hour period?

A

Fed signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are huge basis’ for several low-carb fad diets?

A
  • Changes in Insulin:Glucagon
  • Glucose curves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the reality of the evidence on GI fad diets?

A

That energy intake, in the form of high carb intake and/or high fat intake, cause fat storage.

It is not necessarily a function of high GI foods alone.

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

What are the goals of the body when adapting to fasting?

A
  1. Meet energy needs
  2. Meet glucose requirements
  3. Spare protein (lean mass)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How many kcals of fuel does the brain need per day?

What kind of fuel is preferred?

A
  • approximately 500 kcal per day
  • Water-soluble source of energy (usually glucose)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the energy paradox?

A

That almost all energy is stored as fatty acids (not glycogen), which cannot be converted to glucose (needed by brain).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Fuel Flux- Early Fasting

A

Fuel Flux- Prolonged fasting

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

What are the sources of glucose in the five stages of fasting? When does ketone body use become predominant?

A
  • Exogenous (up to 4 hours post meal)
  • Glycogen (between 4-12 hours post meal)
  • Gluconeogenesis (from 12h to approx 5 days post meal)
  • Ketosis (predominant around 5 days post meal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Is glycerol a valid source of glucose? Why/why not?

A

Glycerol is not a valid source of glucose; there isn’t enough glucose produced to maintain proper brain function.

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

Glucose Utilization in Different Stage of Fasting

  • Origin of blood glucose
  • Tissues using glucose
  • Major Fuel of the Brain
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How are ketoacids (ketones) produced?

A

From very large amounts of fatty acid oxidation

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

After an overnight fast, what is the urinary ketone reading?

A

+1 on keto stick

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

What reduces the need for gluconeogenesis during periods of starvation?

A

Ketogenesis producing ketones for brain fuel

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

How are ketones excreted?

A

Via the lungs (acetone breath) and the kidneys

28
Q

Acetoacetate and Beta-hydroxybutyrate are examples of…

A

Ketones

29
Q

Why is hypokalemia associated with ketosis?

A

Ketones need to be “salted out” when excreted by the kidneys; meaning the loss of Na, K, H, or NH4. K is the preferred ion to be excreted (though NH4 would be ideally excreted).

30
Q

What are the problems associated with hypokalemia?

A

Low potassium: weakness, fatigue, muscle cramps/twitching, constipation, arrhythmia, feelings of thirst and excess urination

31
Q

Why will blood glucose levels seem to stabilize after 3 days of fasting and not be reduced further (or to 0) even at 5 weeks of starvation?

A

There will always be the breakdown of fats, proteins… or other substrates to produce glucose.

32
Q

During periods of starvation, insulin levels will _______ while glucagon levels (and fatty acid levels) _______. This also means the I:G will ______.

A
  • decrease
  • increase
  • decrease (though it stabilizes around 3days of fasting)
33
Q

Will the following substrate levels increase or decrease as fasting/starvation duration increase?

  • Acetoacetate
  • Beta-hydroxybutyrate
  • Lactate
  • Alanine
A
  • Acetoace: Increase (ketone)
  • B-OHbut: Increase (ketone)
  • Lactate: Decrease
  • Alanine: Decrease
34
Q

What changes in urinary nitrogen constituents occur after several weeks of starvation?

A

There is much less urea production and more ammonia after periods of starvation.

35
Q

What are renal consequences of starvation?

A
  • Kidneys NEED to be functioning normally for survival (important in keto diets too)
  • Ammonia=toxic; need to hydrate more to excrete properly
  • Acid/base balance changes need to be controlled by kidneys
36
Q

What can we determine about EI/EE, N-balance and N-intake from this graph?

****keeping in mind the intakes/DRIs for protein are changing****

A
  • When EI/EE is <1, N-balance will always be negative. Need to compensate with more protein intake
  • When EI/EE is >1, you can reach N-balance=0 or positive balance at lower intakes of protein
37
Q

What can we determine from this graph concerning nitrogen balance and EI?

A

When EI is lower, a much higher protein intake is needed to maintain a neutral nitrogen balance. The current DRI of 0.8 g/kg/day are too low to hit those numbers. In weight reduction diets, the proportion of protein intake needs to increase.

38
Q
A
39
Q

Severe weight loss can encourage drastic physiological changes. How does it affect the cardiovascular and renal systems (3) and the immune function (1)?

A
  • Cardiovascular/Renal:
  • Lower cardiac output, heart rate, BP and blood volume
  • Higher tachycardia (compensatory mechanism)
  • Higher stress on kidneys (acid/base balance)
  • Immune function:
  • Lower T-cell function/lymphocytes
40
Q

Severe weight loss can encourage drastic physiological changes. What occurs to gastrointestinal function (3) and to electrolytes (1)?

A
  • Gastrointestinal Function:
  • Less lipid absorption (steatorrhea)
  • Less gastric, pancreatic and bile secretion/production
  • Less villous surface area
  • Electrolytes:
  • Potassium losses (LBM and intracellular losses)
41
Q

True/False:
CNS functions are not disrupted when an individual undergoes massive weight loss.

A

False

42
Q

What is the refeeding syndrome?

A

Metabolic complications associated with nutritional repletion

43
Q

What causes the refeeding syndrome?

What occurs physiologically during this cause?

A
  • Shift back to glucose as main fuel
  • rapid fluxes of insulin (CHO load); rapid shift of electrolytes and intracellular ions to intracellular space (PO4, K, Mg); sodium and water retention
44
Q

What are the symptoms associated with refeeding syndrome?

A
  • fatigue
  • lethargy
  • dizziness
  • muscle weakness
  • arrhythmia
  • hemolysis
  • edema
45
Q

What causes ECF expansion during refeeding syndrome?

A

Edema from increased Na intake and electrolyte imbalances

46
Q

What can the increased glycogen synthesis during refeeding syndrome cause?

A

May lower serum PO4 and K concentration

47
Q

How is the REE increased during refeeding syndrome?

A

Due to the reversal of starvation and LBM rebuilding

48
Q

Intake of carbohydrates during refeeding causes an increase in insulin secretion. What physiological changes occur due to this?

A
  • Fed signal is now present and uptake into cells is resumed
  • N retention is stimulated
  • Stimulation of cell synthesis, growth and rehydration
49
Q

What are the steps involved in refeeding?

A
  1. Normalize fluid and electrolyte imbalances
  2. Provide mixed diet at maintenance energy levels
  3. Provide protein at 1.5-2 g/kg current body weight/day
  4. Monitor serum electrolytes, weight, intake and output
50
Q

When normalizing fluid/electrolyte imbalances during the refeeding process, what needs to be supplemented and what must be limited?

A
  • Supplement: PO4, K and Mg (infusion)
  • Limit: Na and fluid in first few days (avoid retention)
51
Q

When providing a mixed diet at maintenance energy levels during refeeding, what needs to be supplemented? Why do we start with a 25% dose of 100-150g of glucose despite needing that level to stop LBM breakdown?

A
  • Supplement: Thiamine (cofactor in CHO metabolism)
  • To avoid refeeding syndrome and establish a tolerance; increase the amount of glucose gradually to avoid it
52
Q

Why do we provide protein at levels of 1.5-2 g/kg current BW/day when refeeding?

Why do we start with only 20 g/day?

A
  • To promote anabolism and replenish LBM
  • To allow the enzymes in the urea cycle to adapt
53
Q

What typically occurs in individuals who lose weight following dietary restrictions after 24 months?

A

They typically regain most of the weight.

54
Q

What is considered successful weightloss?

A

If the individual is able to maintain the weight loss for a period of 24 months

55
Q

What physiological changes related to energy storage occur after diet-induced weight loss?

A
  • Lower energy expenditure
  • Lower fat oxidation
  • Lower thyroid hormones
  • Higher cortisol

OVERALL EFFECT= INCREASED FOOD STORAGE

56
Q

What physiological changes related to food intake occur after diet-induced weight loss?

A
  • lower leptin, PYY and amylin (appetite suppressors)
  • lower insulin
  • higher ghrelin (appetite stimulant)

OVERALL AFFECT= INCREASED FOOD INTAKE urges

57
Q

How long do the physiological changes associated with increased food storage and increased food intake urges last after diet-induced weight loss?

A

They may persist >1 year after weight loss

58
Q

What countermeasures does the body employ when having undergone weight loss?

A
  • Lower EE- Metabolic Adaptation
  • REE lowered by around 15% kcal per kg lost; more than what is expected at the new body weight + composition
  • Increased Appetite
  • increased hormone activity
  • persists > 1 year
  • improved food reward, palatability and olfaction
59
Q

When do metabolic adaptations occur in the body?

A
  • In response to energy deficit and weight loss
  • In response to increasing exercise
60
Q

In general, the metabolic adaptation to energy deficits and weight loss leads to…

A

…a reduction in EE to a greater degree than predicted from changes in body composition.

  • *Measured REE < Predicted REE**
  • energy gap of 200-250 kcal
  • can continue for years
  • might be related to reduced sympathetic drive, thyroid function, and leptin
61
Q

In general, the metabolic adaptation to increased exercise leads to…

A

… a decrease from the initial increase in EE from just starting exercise (adapting to training).

  • *With further training…**
  • no further increase in EE despite increased volume and intensity of exercise
  • might be due to biomechanical efficiency
62
Q

What is energy partitioning?

A

Isocaloric diets differing in macronutrient composition; may result in preferential partitioning of energy storage toward body fat and away from body protein

63
Q

From the current studies available, is there a difference in low carb vs low fat diets when looking at EE and fat loss?

A

There is no difference in effects of carb:fat ratio in EE and fat loss.

64
Q

Diets ____ in protein _______ influence fat-free mass during weight loss and weight gain.

A
  • high
  • positively
65
Q

How does high protein intake positively impact fat-free mass during weight loss/gain?

A
  • In low EI diets: higher protein minimizes reduction of REE by about 150 kcal/d
  • In high EI diets: higher protein increased REE (alongside increase in FFM)
  • Helps maintain weight after weight loss: more satiating, prevents overeating*

NUTR 344: Clinical Nutrition 1 (15 decks)

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