Dietary Fat And Exercise Flashcards
What percentage of lipids consumed do triglycerides make up?
90%
List non-energy producing metabolic functions of phospholipids
Imparting structure to cell membranes
Emulsification
Molecular signaling
Participating in biochemical reactions and pathways, such as hormone synthesis
What foods contain phytosterols and what lab value do they reduce?
Plants
LDL
What are the body’s uses for cholesterol?
Essential component of cell membrane structure
Essential component in many physiological pathways such as the biosynthesis of steroid hormones
How many carbons do the below fatty acids have?
Volatile
Short chain
Medium chain
Long chain
Very long chain
Volatile: 1-3
Short chain: 4-6
Medium chain: 6-12
Long chain: 14-22
Very long chain: >22
What is the most commonly consumed length of fatty acid chains?
16-18 carbons
Most common recommended daily intake of fat
1 g/kg/d
When MAY acute fat restriction be beneficial?
Just before an event
During carb loading
When preferred macronutrients or GI comfort have priority
The 2014 American College of Cardiology and American Heart Association believe what regarding fat intake
Overall dietary pattern is more important than individual food choices
What diet does the ACC/AHA allow to exceed 35% daily fat intake?
Mediterranean diet
What to consider when making dietary fat recommendations to athletes?
Total fat intake for training and competition needs
Importance of promoting GI tolerance
Whether added fat intake is displacing other essential macronutrients
Do recommendations align with public health guidelines
Saturated fat daily intake recommendations
<10%
Trans fat daily intake recommendations
<1%
Omega 3 and omega 6 daily intake recommendations
Omega 3: 0.6-1.2%
Omega 6: 5-10%
Storage forms of fat
Plasma free fatty acids
Muscle lipid
Stored lipid in adipose tissue
What are triglycerides stored in muscle cells called and when can they provide critical energy
Intramyocellular lipids
During long endurance events
What does hormone sensitive lipase (HSL) do?
Export adipose tissue triglycerides into circulation as protein bound fatty acids
What is HSL activity stimulated by
Epinephrine
Norepinephrine
Glucagon
Adrenocorticotropic hormone
Thyroxine
Growth hormone
Factors that affect lipid oxidation
Exercise intensity and duration
Sex
Intake before and during exercise
Where do most fatty acids come from when used as a fuel source
Adipose tissue
Muscle lipid depots EMCL and IMCL
And lipoproteins
What percentage of energy does VLDL provide during prolonged exercise of moderate intensity
10%
What is the difference between males and females with regard to IMCL, lipid oxidation, and muscle fiber types
Females tend to have more IMCLS due to aerobic capacity, fitness level, and training history
Females tend to have higher fatty acid oxidation rates during moderate intensity prolonged endurance events
Females tend to have more type i fibers and capillary density
When is carb oxidation higher than fatty acid oxidation and vice versa
Carb oxidation is higher in 60-90 minutes
Fatty acid oxidation is higher in >90 minutes
What is the limitation of fatty acid utilization during high intensity exercise
Inverse relationship between lipolysis and lactate concentrations
Inability of mitochondria to completely oxidize fat with limited oxygen availability at greater than 85% VO2 max
At what % VO2 max are lipids maximally contributing to energy
60-65%
Moderate intensity
What maximizes lipid oxidation rates more, exercised induced adaptations or dietary strategies
Dietary strategies
Describe the most common fat adaptation intervention
Follow a high fat, low carb diet for 5-14 days while maintaining normal training.
Protocols may be implemented with or without carbohydrate restoration coupled with a training taper leading up to competition
What are the cellular outcomes that training low enhances
Increased maximal mitochondrial enzyme activities or mitochondrial content
Increased rates of lipid oxidation
What are the most common effects of following a high fat, low carb diet on RER, fat oxidation, muscle triglyceride stores, and glucose oxidation
Respiratory exchange ratio: decrease
Fat oxidation: increase
Muscle triglyceride stores: increase
Glucose oxidation: decrease
What is RER and why is it used?
Respiratory exchange ratio: ratio between CO2 produced vs oxygen consumed
Used to measure whether fat or carbs are the primary fuel source
0.7 - fat
1.0 - carbs
What are the most likely effects of high fat diets on moderate and high intensity exercise
Moderate: at best can match high carb diets
High: impaired performance
When should fat be restricted to make weight
2-3 days before weigh in
Negative effects of fat restriction
Low energy availability
Unwanted loss of muscle mass
Menstrual dysfunction
Hormonal disturbances
Suboptimal bone density
Increased risk of fatigue, injury, and illness
Impaired adaptation
Prolonged recovery process
Sources of omega 3 and omega 6 fatty acids
Omega 3: fatty fish, walnuts, canola oil, flaxseed
Omega 6: most, but not all other plant foods
How many hours before competition should fat be limited
1-2 hours
In a meal 3-4 hours before an event, what is the preferred percent of fat
Less than 30%
Negative effects of excessive omega 3 supplementation
Increased oxidative stress markers post exercise
Greater risk for immunosuppression
Greater risk for prolonged bleed times
Recommended safe intake of omega 3 supplementation
3g of EPA/DHA
Recommended adequate intake of omega 3 fatty acids in adult men and women
Men: 1.6 g/day
Women: 1.1 g/day
