Carbohydrates and Fats Part 2 W2 Flashcards
What are daily carbohydrate recommendations based on?
Body weight
NOT % of energy intake
What are the 2 main methods of dieting few days prior to exercise?
General fuelling up
Carbohydrate loading
What does general fuel fuelling up “carbohydrate target” look like when preparing days before an event which lasts >90minutes?
7-12g/kg/d as per daily fuel needs
What does carbohydrate loading “carbohydrate target” look like when preparing days before an event which lasts <90minutes?
10-12g/kg/d for 36-48h pre-event
What are the 4 major considerations of pre-event dieting?
Practicality
Sustainability
Necessity
Side effects
On the day of an event, what does typical pre-event fuelling look like?
1-4g/kg body mass consumed 1-4h before exercise
Exercise duration is typically >60min
What is the main goal of “day of event” fuelling?
Ensuring liver glycogen stores are high
What is the main goal of “post-event” fuelling?
Replenish muscle glycogen after training/competition
What are the functions of fat?
Fuel source
Protection of vital organs
Cell membranes constituents
Precursors of bile, hormones and steroids
Essential fatty acids and fat-soluble vitamin intake
Palatability
What does a high fat, low carb diet result in? (Fat adaptation, Carbohydrate restoration)
Increased fat oxidation
Deceased carbohydrate oxidation
Spared muscle glycogen
What type of exercise intensity does fat adaptation impair?
High-intensity
What is a ketogenic diet?
(CHO g,Fat %, Protein requirements g/kg/d)
<50g carbohydrate per day
Fat Intake>70-80% energy
15% or 1.5g/kg/d protein (no more than 25%)
What does a ketogenic diet increase?
Use of fat as a muscle fuel (elevated blood levels of ketones and tissue adaptations)
Ensures there is adequate sodium and potassium
How long does it take until there is a keto-adaptation?
2-3 weeks
What type of performance can a shift to fats and ketone as primary fuels see benefits?
Endurance performance
What does keto-adaptation ensure?
Stable fuel source for exercising muscle in the face of low CHO availability
What induces ketosis?
Lowering CHO intake
Increasing Fat intake
What is the daily target of CHO during light exercise?
3-5g/kg/d
What is the daily target of CHO during moderate exercise? (1h per day)
5-7g/kg/d
What is the daily target of CHO during high exercise? (>1-3h)
6-10g/kg/d
What is the daily target of CHO during very high exercise? (>4-5h)
8-12g/kg/d
When do you use general fuelling up?
Prep for events lasting <90min exercise
When do you use carb-loading?
Prep for event >90min in sustained, intermittent exercise
How do you decide the recommendation for CHO breakfasts prior exercise?
The closer you get to the start to the event, the less you can consume
When do you use low fat meals before exercise?
Last 2-3h before
What is the window of optimal CHO resynthesis post exercise?
First 4 hours
Why may CHO and Protein co-ingestion maximise glycogen synthesis?
It induces a greater insulin spike which activates glycogen synthase
How much proportion of saturated fat contributes to energy intake?
Less than 10%
How much chronic fat contribution to energy intake is discouraged when undergoing weight loss/ body composition changes?
Less than 20% of energy intake
What is the fat adaptation, carbohydrate restoration model?
Go through a period of hard training consuming high fat and have depleted glycogen storage
They then rest and have high CHO to increase glycogen storage
Does fat adaptation, carbohydrate restoration improve time trial performance (cycle)?
No effect
What is fatigue?
Lack of CHO availability and inability to efficiently use fat stores
How does the ketogenic diet effect fat oxidation?
Increased rate of fat oxidation over a range of exercise intensities
How does the ketogenic diet effect exercise economy?
Reduced economy= increased oxygen demand
How does the ketogenic diet effect exercise performance in elite endurance athletes?
In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impaired performance in elite endurance athletes
What do daily carbohydrate intake targets for a athlete reflect (2)?
A periodised approach
Flexibility to the demands of training and competition
When does CHO and Protein co-ingestion maximise glycogen synthesis?
At sub-optimal carbohydrate intake
