Metabolism of weight loss Flashcards Preview

Clinical nutrition > Metabolism of weight loss > Flashcards

Flashcards in Metabolism of weight loss Deck (23):

Which tissue have the most energy expenditure?

Liver (21%)
Muscle (22%)
Brain (20%)


Which tissue has the highest energy storage?

Adipose tissue


Which tissue is insulin sensitive?



After a meal, what is the initial increase?

- Insulin
- GLucose
- Pyruvate
- Lactate
- Triglycerides
- Alanine
- TOtanl a.a.
- I: G


After a meak, what is the inital decrease?

- Lgucagon
- free fatty acid
- Ketoacids
- Glycerol
- Urea nitrogen


What is reactive hypoglycemia ?

Insulin remains in the circulation for a longer time. Glucose, instead of going to a steady state, blood glucose will continue to go down.

Happening more in people with insulin resistance, early diabetes, associated with high BMI.


What are the 3 goals to adapt fasting?

1. Meet energy needs
2. Meet glucose requirements
3. Spare proteins (lean mass)


What are the 3 principles of the energy paradox?

1. The brain needs 500kcal of water-soluble fuels (usually glucose/day)

2. Almost all energy is stored as fatty acids, not as glycogen

3. Fatty acids cannot be converted to glucose..


What is a concern regarding ketoacid excretion?

- When ketones are excreted through kidneys, they have to be salted out, which involves the loss of either Na, K, H or NH4

- Ideally NH4 is excreted, because it is a waste product

- However, K is preferred ion to be excreted.

- Can lead to hypokalemia


Ketogenesis will start after ____ h of fasting

GLycogen use can last for _____

4-5 hours

28 days


After several weeks of starvation, urea nitrogen will __________ and ammonia will ________.

decrease (urea)

increase (ammonia)


If you are on an energy _______ you need _____ protein to maintain __ balance

energy DEFICIT


N balance


What are the 2 forbes prediction?

1. During fast, obese individuals will lose less nitrogen (hence less lean body mass) than will thin people.

2. The fatter the subject, the less contribution of LBM to total weight loss on energy restricted diets.


What are cardiovascular and renal physiological changes to severe weight loss?

DEcrease cardiac output, heart rate, blood pressure

Increase tachycardia (resting heart rate)

Increase stress on kidney (acid/base balance)


What are immune functions physiological changes to severe weight loss?

Decrease T-cell function/lymphocytes

Decrease cytokines


What are gastrointestinal functions physiological changes to severe weight loss?

Decrease lipid absorption

Decrease gastric, pancreatic and bile secretion/production

Decrease villous surface area


What are physiological changes regarding electrolytes in reaction to severe weight loss?

Potassium losses (LBM and intracellular losses)


What are the main differences in responses between high fat/low CHO and High CHO/low fat diets?

- High FA
- More ketoacids
- More Serum uric acid
- Less insulin

in High fat/ low CHO


What are side effects of ketogenic diets?

- Hyperuricemia
- Hypocalcemia
- Irritability
- Lethargy
- Appetite suppressant
- Carnitine deficiency

- Elevated serum lipids (when iso-caloric)
- Constipation (unless MCT oil used)
- Water soluble vitamin deficiency
- Renal stones
- Growth inhibition
- Acidosis and excess ketosis during illnesses
- Optic neuropathy (due to thiamine deficiency)


What are the causes of the refeeding syndrome? What does it cause?

Shift back to glucose as main fuel

=> Rapid shift of electrolyes and intracellular anions and cations to intracellular space (Mg, K, PO4)

=> Sodium and water retention

=> Rapid fluxes of insulin due to CHO load


What are symptoms of refeeding syndrome?

- Fatigue
- Lethagy
- Diziness
- Muscle weakness
- Edema
- Arythmia
- Hemolysis


What are physioloical changes during nutritional repletion (refeeding syndrome)?

- ECF expansion (edeman from increased Na intake)

- Glycogen synthesis

- Increased BEE

- Increased insulin secretion from CHO

- Stimulates N retention

- Stimulates cell synthesis, growth, and rehydration


What are the steps in refeeding?

Normalize fluid and electrolyte balance
- Mg, PO4, K using supplementation
- Limit Na ad fluid intake in the first few days

Provide mixed diet at maintenance energy levels
- To establish tolerance and avoiding refeeding syndrome
- Thiamine or multivitamin supplementation

Provide protein (1,5-2 g/kg current body weight) / day
- Start with 20g/day due to urea cycle enzyme adaptation
- To replenish LBM

Monitor serum electrolytes, weight, intake, outputs...