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Clinical nutrition > Metabolism of weight loss > Flashcards

Metabolism of weight loss Flashcards

1
Q

what are the 3 parts of the body that expends more energy at rest

A
  1. brain (20%)
  2. liver (21%)
  3. skeletal muscle (22%)
    however, skeletal muscle is bigger than the other organs
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2
Q

most energy is stored as

A

adipose tissue

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3
Q

what is the diff between 100 kcal of glycogen, protein and lipids

A

glycogen and protein are stored with majority water and adipose tissue is mostly fat
for 100 grams of protein or glycogen - 80% is water. But for 10g of adipose tissue it is almost 10g for fat

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4
Q

in the beginning of weight loss the first thing we lose in glycogen and protein is

A

water

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5
Q

what is the path of ingested glucose in out body

A

ingested glucose goes in our liver, and then it is transformed in VLDL to form adipocytes
OR muscle and adipocytes are sensitive to ingested glucose and it can also go to CNS, RBC

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6
Q

describe the blood glucose curve and the hormones or pathways that takes place
- uptake slope
- decay slope
- steady phase

A
  • uptake slope:
    insulin release, increase in GI abs, glycolysis, decrease in glycogenolysis and gluconeogenesis
  • decay slope:
    high insulin: high tissue uptake, high glycogenesis

increase in glucagon
- steady phase
decrease in insulin high in glucagon
high glycogenolysis and gluconeogenesis

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7
Q

what is the response to a meal (what increases and decreases)

A

increase: insulin, glucose, lactate, pyruvate, triglycerides, alanine, total amino acids

decrease: glucagon, free fatty acids, ketoacids, glycerol, urea nitrogen

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8
Q

what is the diff of the blood glucose curve between a person who is insulin resistance and normal

A

normal: the blood glucose will pick after h and then it will go down

insulin resistance: blood glucose will pick very high one hour after and then it will go extremely down after 4 hours after eating (below normal) which is called reactive hypoglycemia (resistant to insulin and glucagon)

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9
Q

what is reactive hypoglycemia

A

when the blood glucose level go extremely down normally after 4h after eating. Glucagon resistance

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10
Q

how do people sell fad diet with the carb-insulin model of obesity

A

they say that carbs have the most effect on insulin therefore it favor energy storage and weight gain. They say that eating food that has a low GI favors weight loss by controlling the amount of carbs and insulin in the food

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11
Q

what causes fat storage

A

high carb intake and high fat intake cause fat storage and not necessarily GI alone

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12
Q

What are the goals when adapting to fasting

A
  1. meet energy needs (for all of our tissue live and survive)
  2. meet glucose reqt (important to maintain glucose level)
  3. spare protein (conserve mass)
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13
Q

what is the energy paradox

A
  1. the brain needs around 500 kcal of water soluble (glucose) fuels per day
  2. almost all energy is stored as fatty acids and not glycogen
  3. fatty acids cannot be converted to glucose
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14
Q

what happens to the fuel flux after 24h of fasting (2000 kcal)

A
  1. triglycerides releases fatty acids in the circulation goes to muscle and liver
  2. muscle send amino acids to the liver
  3. liver produce glucose that goes into the cori cycle ( goes to the brain, RBC) and it produces ketones
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15
Q

what happens to the fuel flux after prolonged fasting (1500) compared to early fasting

A

you have less amino acids in the muscle, less glucose goes to the cori cycle. One part becomes urine and less glucose goes to the brain

LOW insulin

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16
Q

What is the glucose utilization from different sources in fasting

A
  1. exogenous
  2. glycogen
  3. gluconeogenesis
  4. ketoacids
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17
Q

when glucose stores are depleted what is the other fuel for the brain

A

ketone bodies

18
Q

how can ketoacids be secreted

A

it can be secreted by the lungs and kidney

19
Q

what are the implications of secreting ketones

A

because they are acids they need to be buffered with potassium so it leads to hypokalemia

20
Q

the diff of urinary nitrogen constituents between normal and starvation

A

normal: a lot of urea, less ammonia
starvation: less urea and more ammonia.
you have less protein coming therefore there is less urea excretion

21
Q

what is the consequence of starvation in renal

A
  • need normal kidney function
  • ammonia is toxic so needs more water for excretion
  • acid/base balance changes in response to starvation and it needs to be controlled by the kidneys
22
Q

what is the relationship between nitrogen intake, energy intake and N balance

A

with a less nitrogen intake ( protein) you will have a negative nitrogen balance until you reach the reqt by eating more protein

person that has a deficiency will take more protein intake to reach a balance nitrogen balance

23
Q

what is the difference between 2 groups that have 2 diff nitrogen balance and that want to loose weight

A

in the beginning the 2 groups drops of nitrogen balance but then the one that eats more protein will reach nitrogen balance and maintain over time the weight and the one that eat not a lot of protein will have a negative nitrogen balance

24
Q

explain the forbes equation

A

a graph of lean body mass to change weight by body fat. The more a person is fat the harder it is to change weight

25
Q

what are the 2 predictions of Forbes equation

A
  1. during fast, obese individuals will lose less nitrogen than thin people
  2. the fatter the subject the less the contribution of LBM to total weight loss on energy-restricted diets
26
Q

what are the physiological changes to severe weight loss in
cardiovascular and renal
immune function
gastrointestinal function
electrolytes

A
  • cardiovascular and renal:
    decrease cardiac output, heart rate, BP
    increase tachycardia
    increase stress on kidneys (acid/base balance)
  • immune function
    decrease of T cell function/lymphocytes
  • gastrointestinal function
    decrease on lipid absorption
    decrease on gastric, pancreatic and blue secretion/production
    decrease of villous surface area
  • electrolytes
    potassium losses
27
Q

what is the refeeding syndrome

A

refeding a person that has being fasting for a long period of time or that is on a diet for a long period of time

28
Q

people that are on a diet for a longtime or fatsing what they were used to and what it will change

A

they were used to keto acids and they will shift to glucose

29
Q

what should we expect when they shift back to glucose

A
  • rapid fluxes of insulin due to CHO load
  • rapid shift of electrolytes and intracellular anions and cations to intracellular space
  • sodium and water retention
30
Q

what is going to be their symptoms when they are back to glucose (refeeding syndrome)

A

fatigue, lethargy, dizziness, msucle weakness, arrythmia, hemolysis and edema

31
Q

what are the physiological changes during repletion

A

ECF expansion : edema from increased Na intake and electrolyte imbalances

Glycogen synthesis lower serum PO4 and K concentrations

Increased REE : lean body mass rebuilding

increased insulin secretion form carb intake : stimulates Nitrogen retention (retention of protein), stimulates cell synthesis, growth, and rehydration

32
Q

what are the steps in refeeding

A
  1. normalize fluid and electrolyte imbalances
    use supplementation, limit sodium in the first days
  2. provide a mixed diet at a maintenance energy level
    to establish tolerance and avoid refeeding syndromes. Aims 100-150g glucose to stop LBM breakdown + thiamine supplementation
  3. provide protein at 1.5-2g/kg
    start with 20g/day to urea cycle enzyme adaptation
  4. monitor serum electrolytes, weight, intake and output
33
Q

what is the weight loss trajectory

A

normally you regain some weight but less than you started with

34
Q

what are some physiological changes after diet induced weight loss

A

high energy store and high food intake

35
Q

what are the causes of a high energy store and a high food intake

A

high energy store : high cortisol, low fat oxidation, low energy expenditure

high food intake: less satiety bc the hormones (leptin, insulin, amylin decrease), and high ghrelin so higher appetite

36
Q

what are the weight loss countermeasures

A

lower energy expenditure : REE decrease bc of the metabolic adaptation, decrease in P.A, decrease TEF

and higher appetite: less satiety more hunger bc of the hormonal adaptation (ghrelin increases an PYY decreases)

37
Q

true or false
obese have a higher REE than lean

A

true

38
Q

metabolic adaptation

A

it is when your body adjust to reducing the REE

39
Q

explain the biggest loser study after 6 years

A

they lost a low of weight in the program and after 6 years they went to review their weight. They gained weight compared to when they were in the show but it is less than when they started however, the amount fo calories they are eating is the same as it was during the show meaning there was some metabolic adaptations

40
Q

Are there some difference in effects of carbs and fat ration in energy expenditure and fat loss

A

no

41
Q

which type of macronutrient has the more + influence on weight loss and gain of lean mass and REE and maintain new weight

A

protein

Clinical nutrition (11 decks)

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