Carbohydrate and Fat Flashcards

1
Q

At what intensity is fat mainly used?

A

Fat was mainly used at low intensity
- More efficient to get energy from glycogen at high intensity
- Consequences of shifting to fat, when carb stores are depleted causes lower performance

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2
Q

Name some:
- monosaccharides
- disaccharides
- oligosaccharides
- polysaccharides

Which of these is most likely to be contained in sports drinks?

A
  • glucose, fructose, galactose
  • sucrose, maltose, lactose
  • maltodextrin
  • amylopectin(starch), amylose

Glucose can be interchanged with maltodextrin as it
Is easy to breakdown, glucose and fructose also found
In sports drinks
* Glucose and galactose are primarily absorbed via active
transport of Na+ by the sodium-dependent
luminal transport protein

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3
Q

How is glucose metabolised in a fasted state?

How is glucose metabolised in a fed state?

A
  • Main store of glucose in the liver
    In fasted state glucose is the main source of Brain energy
  • Pancreas releases insulin to increase uptake at muscle, liver etc
    The consumption of easy to digest CHO rich food 3hrs before exercise increases muscle & liver glycogen by 11-15%
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4
Q

What are the types of fats/lipids?

what food sources are they found in?

A
  • Fats, oils, phospholipids and sterols
  • Occur naturally in wide variety of foods
    • Animal adipose tissue
    • Milk and milk products
    • Seeds, nuts and oils
    • Eggs, fish oils
      95% dietary fat intake is from triacylglycerols (TAG)
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5
Q

How are fatty acids classified?

A
  • Number of carbon atoms in the chain
  • Number & position of double bonds in the chain
  • Saturated (0 C = C) –> Palmitic acid 16:0
    ○ 16 carbon and NO double bonds
  • Monounsaturated (1 C = C) –> oleic acid (18:1n-9)
    ○ 18 carbons, 9th from the right is where double bond is (1 double bond)
  • Polyunsaturated (2+ C = C) –> Linoleic acid (18:2n-6)
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6
Q

What is the general CHO intake of an athletes with… training load:
- light
- moderate
- high
- very high

A
  • 3-5 g/kg/d
  • 5-7 g/kg/d
  • 6-10 g/kg/d
  • 8- 12 g/kg/d
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7
Q

Describe short term fat loading:

A
  • 3 day high fat (65% fat; 9% CHO) or high carbohydrate (82% CHO; 9% fat) diet
  • 70% VO2Max to fatigue in 10oC and 30oC
  • Impaired performance with short term high fat diet
  • There was very little difference in heat, substrate in the heat is not the primary factor(dehydration is)
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8
Q

What happens during longer fat loading?

What may be a potential benefit of a High fat diet?

A
  • Normal (30±8%) or high (69±1%) fat diet for 15 days
  • Increased fat oxidation during submaximal exercise
  • Decreased carbohydrate oxidation during submaximal exercise
  • No difference in 40 km cycling time trial, May not have benefitted or hindered the performance
  • The only benefit of a high fat diet is time to exhaustion at 60% of Vo2max
    High CHO group have depleted muscle glycogen by the time they reach 60% Vo2max
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9
Q

Describe the process of diet periodisation:

A
  • Do positives (glycogen sparing) and negatives (lowered CHO stores) cancel each other out?
  • If adaptations to metabolism allow increased fat oxidation could this be combined with high CHO stores?
  • High fat diet followed by rapid glycogen storage?
  • High fat diet decreased muscle glycogen
  • 1 d high CHO restored muscle glycogen
  • High fat diet decreased rate of muscle glycogen use
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10
Q

Name some benefits of diet periodisation:

A
  • enhanced training quality/intensity with high CHO availability
  • enhanced cellular signalling and adaptation with training with low muscle glycogen
  • less muscle glycogen is used
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11
Q

What effects were found for a low CHO, high fat diet in elite race walkers?

What benefit was shown?

A
  • LCHF were more efficient, optimum
    Approach is periodised CHO intake, leads to mitochondrial biogenesis
  • Showed higher reductions in economy include observations, from a previous study of a 5 day non-ketogenic LCHF, of an uncoupling of mitochondrial respiration specifically associated with high fat exposure
  • Also alters oral microbiome reducing anaerobic bacteria involved in the conversion of dietary-derived nitrate to nitrite - therefore effects all associated NO functions
  • These LCHF and endurance performance studies often have flaws of involving the implementation or scientific control.
  • CHO intake less than muscle fuel needs while consuming high amounts of dietary fat causes adaptations to increase availability of muscle fats and capacity to oxidise them as muscle fuel
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12
Q

What is the impact of training with low CHO availability?

A
  • Potential to increase molecular adaptations
  • Increase in AMPK and PGC1-α leading to increased mitochondrial biogenesis
  • Reduced self-regulated training volume à pick the right session/ method
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