Dietary Fat and Exercise Flashcards
Do fats have a high or low TEF? What does this mean?
low TEF - low energy cost for digestion/storage
Do fats have an efficient storage?
yes, stored with very little water (unlike carbs)
What fat-soluble vitamins are absorbed with fats?
ADEK
What is the energy of 1g of fat?
9kcal/gram
What are the 4 storage forms of fats? Which storage form stores the most energy?
most energy stored in adipose tissue triglycerides
1-serum free fatty acids (7)
2- serum triglycerides (75)
3- muscle triglycerides (2,500)
4- adipose tissue triglycerides (80,000)
What is ketosis?
When body switches to using fat as a dominant fuel source.
Often after 12 hrs fasting - breaking down adipose tissue triglycerides.
What are lipids?
What is their composition?
dietary fats, insoluble in water
composed of carbon, hydrogen, and oxygen
What are triglycerides composed of?
glycerol backbone, and 3 FA attached to each glycerol
What are the types of lipids?
TG, phospholipids, cholesterol
What is the AMDR for fat?
For 1-3yrs, 4-18yrs, and 19+yrs?
1-3yrs: 30-40%
4-18yrs: 25-35%
19+yrs: 20-35%
What is the recommended dietary allowance (RDA), adequate intake (AI) or upper limits (UL) for total fat?
No RDA, AI, or UL
except for infants AI: 30g/day
6-12M AI: 31g/day
What is the recommendations for fat intake (types / degrees of saturation)?
saturated fatty acids (10%)
minimize trans fat intake
max 7-10% from saturated and trans fats (combined)
monounsaturated FA (MUFA) - 10%
polyunsaturated FA (PUFA) - 10%
Is there a benefit to a low fat diet for athletes?
no, no benefit for this. consuming <20%kcal from fat is not beneficial, neither is a high fat diet.
What is esterification? When is this process favoured?
formation of triglycerides: combination of an acid and alcohol (glycerol) ester
process of formation favoured after eating a meal
What is fat lypolysis or hydrolysis?
When is this process favoured?
the breakdown of TGs to yield energy from FAs and glycerol
process favoured during exercise, low cal dieting, low energy availability, fasting/starvation, decreased insulin concentrations; increased GH, cortisol and catecholamines (fight or flight response); when body is cold
When the body is cold is lypolysis or TG formation favoured?
favours lipolysis
the 3 hydrolysis reactions for lipolysis are catalyzed by what enzyme?
hormone-sensitive lipase
What are the 2 major fates of fat mobilization?
re-esterification to TG (storage of fat)
exit from the fat cell (as FFA or attached to albumin)
What is beta-oxidation?
mobilization of fatty acids into acetyl-CoA
Then acetyl-CoA is processed via Krebs cycle and ETC system to produce ATP
At rest, what % of energy is supplied by metabolism of fats?
~60% (when consuming mixed diet)
What happens as plasma FFAs are being used up?
FFA are being mobilized from adipose tissue
what % of FFA released get “re-esterfied” back into triglycerides at rest?
70% - build back up into TG and stored in adipose tissue
what are 2 major sources of ATP for exercise?
CHO and fat
FFA - mainly LCFA
FAs are used by muscle during exercise and may be derived from:
from plasma triglycerides, plasma FFA, fatty acids from intramuscular TGs