Lecture 11 Flashcards by Calum Macindoe

Which vitamins are fat soluble and which are water soluble?

fat soluble = ADEK

Water soluble = B, C

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What are four essential amino acids?

Histadine
Lysine
valine
Leucine

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There are two types of cross over concepts what are they?

Intensity, - where beyond a point CHO is primary fuel source

Length, beyond 2.3hrs CHO is depleted and FAT is the fuel source

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What are four non-essential amino acids?

Proline
Glutamate
Glycine
Tyrosine

All made by the body

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What does fat oxidation require?

Oxygen always, unlike CHO which can do it with or without

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How much intramuscular fat stores does a 80kg man have?

0.3kg = 11Mj

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How much adipose tissue does an 80kg man have?

12Kg= 430Mj

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How much energy does 1Kg of fat have?

7,700Kcal

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On average how much body fat does a male and female have?

Males = 15%
females = 20%

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So why cant people run 1300km despite having enough fat stores to do so?

Cross over concept at around 0.5VO2max the ratio of CHO and Fat used as fuel sources are equal, beyond this, CHO becomes primarily used.

Therefore intensity determines fuel source, also fat oxidation is limited..

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When fats are oxidized where do they come from?

Muscle TG

Plasma FFA

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Whats supplies the blood with FA and GLucose?

Liver = Glucose tupple

Adipose tissue = FA supply

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In an aerobic system what part of the TG are oxidized?

FA and Glycerol enter the krebs cycle

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What limits fat oxidation?

Lipolysis
Mobilization of FA into the blood.
Transport by blood
Beta oxidation
Transport from blood into muscle
Transport from cytosol to mitochondria

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Why is lipolysis a rate limiting step?

Hormone sensitive lipase must be activated

This releases Glycerol from the FA’s

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What hormones act on lipase?

Insulin

Epinephrine (inhibits)

What happens to the FA once released from adipose tissue into the blood?

70% are re-esterfied. (form TG)

Why is FFA into the blood a rate limiting step?

It is dependent on the blood flow to adipose tissue and albumin in the blood.

Why is FFA release into the blood dependent on albumin in the blood?

Albumin has three binding sites for FFA

-Under most conditions only a small amount of FFA binds (unlikely to be the actually limiting step)

How does FA get into the muscle cell?

Two transmembrane transporters:
FABP (FA binding protein)
FAT (FA Transporter)

What moves FA into the cell membrane to the mitochondria?

FABPc

What increases lipolysis at the onset of exercise?

Catecholamines increase lipolysis 3x

Doubles blood flow to adipose tissue
Re-esterfication is halved

Basically FA flow to muscles is greatly increased

At what point in exercise does FA oxidation become greatly deminished?

beyond 75% VO2max

What actually limits FA oxidation (b oxidation)?

Not delivery, in there cell there must be something pushing back, this is the formation of acetyle CoA from glucose oxidation.

Does fat metabolism dictate CHO metabolism, or does CHO metabolism dictate fat metabolism?

Neither, both pathways share the same inhibiting factors (negative feedback mechanisms, though glucose oxidation has more.

What is the difference between fat and glucose oxidation at rest?

• Metabolic demands are not great • Lypolysis proceeds as normal • Fat is getting to the periphery • Nothing is really driving glucose metabolism forward • If we eat, it goes toward storage although increased glucose and insulin will cause some glucose oxidation. • Fat oxidaiton is not tightly regulated.

What is the difference between CHO and FA oxidation at exercise?

* Glycogen is broken down * Glut 4 is moving (translocating) to the cell surface * More type II muscle fibres are being recruited with increase exercise intensity. * Need for oxygen efficient fuel. * CHO use tightly related to energy needs. * Think about glycogen depletion and fatigue.

Should you ingest fat during exercise?

No, no benefit. Body uses CHO mostly anyways

Does fasting provide any benefit for athletes?

it increase lipolysis and FA availability, but no CHO stores, so above 45%VO2max performance is hindered.

What is the goal of a high fat diet?

* The goal of a high-fat diet is to cause changes in activity of key enzymes to increase FFA oxidation. * Diet usually contains >60% fat and

Does a high fat diet provide benefits?

Nope

What are three low GI foods?

Fructose pasta Beans

What are three moderate GI foods?

Whole grain bread Corn Honey

What are three high GI foods?

White bread White rice Baked potatoes

What amount of CHO during exercise is best?

1.2g KG hr