SN - Fat

bethdrysdale94's version from 2017-03-18 16:26

Section 1

Question Answer
Some examples of foods with fats/oils/phospholipids and sterols in themanimal adipose tissue, milk, seeds, nuts, eggs, fish oils.
How much of dietary fat intake is from triacylglycerols? (TAG)95%
What makes up a TAG?Glycerol backbone CH2-CH-CH2, ester link C-O-C=O, 3 fatty acid chains /\/\/\/\/\/\
How do you classify fatty acids?Number of carbon atoms and number of double bonds
What determines saturation?Saturated is zero C=C, monounsaturated is 1 C=C, polyunsaturated is 2 or more C=C
name a saturated fatty acidPalmitic acid (found in palm oil) 16:0
name a monounsaturated acidoleic acid (18:1n-9)
name a polyunsaturated acidlinoleic acid (18:2n-6)

Section 2

Question Answer
What types of exercise does fat contribute to?light and moderate intensity
What is the energy density of fat?9kcal/g
What happens to carbohydrate utilisation (g/min) from fat as running speed increase?decreases, sways more towards muscle glycogen as overall energy cost increases
As time increases, what happens to %of total energy expenditure sourcesmuscle glycogen becomes depleted, as does blood glucose but not as much, so more %energy expenditure comes from fat after long periods of time
Hurley et al (1985) endurance training and energy sourcestudy of triacylglycerol and glycogen sources pre and post training (3-4 times a week: 2h@64% of pre-training VO2max)
What happens to triacylglycerol source post-training?doubles in Hurley's study from 20-40% of energy used
What happens to glycogen utilisation post training?halves in Hurley's study from 70-35% energy used
Why are we interested in fat consumption post training?increased fat oxidation during exercise will spare muscle glycogen

Section 3

Question Answer
How is fat metabolised? (adipose tissue >> Blood)lipid droplet made up of triglycerides in adipose, TGs broken down into 3FFA and glycerol, activated by insulin uptake into cell. FFA transported out the cell by fatty acid binding proteins (FABP), FFA bound to albumin in blood (TG can also come from VLDLs or chylomicrons)
How is fat metabolised? (Blood >> muscle fibre)FFA transported into cell using transport proteins, bound to CoA (fatty acyl-CoA), beta oxidation into acetyl-CoA, kreb cycle >>>> enrgy
Pitsladis 1999 short term fat loading3 day high fat (65%fat;9%CHO) VS high carb (82% CHO;9% fat) diet. 70% VO2max to fatigue in 10degrees C
What was the results of Pitsladis?impairment of performance with short term high fat diet
Goedecke 1999 long term fat loading16 endurance trained cyclists, normal (30%) vs high (69%) fat diet for 15 days, 49km cycling time trial
Results of Goedecke 1999increased fat oxidation during submax exercise, decreased carb oxidation during submax exercise, no difference in cycling time trial
Lambert et al 1994 long term fat loadingfive trained cyclists, 2 week high carb (74% CHO, 12% fat) VS high fat diet (70%fat vs 7%CHO) diet, wingate test then 90% VO2max to exhaustion, then 60% VO2max to fatigue
Lambert et al 1994 resultshigh fat better at wingate, CHO better at 90% VO2 max, high fat better at 60% VO2max by a LONG shot

Section 4

Question Answer
Burke 2000 dietary periodisation on muscle glycogenhigh fat diet decreased muscle glycogen, but 1day high CHO restored muscle glycogen, and high fat diet decreased rate of muscle glycogen usage
Burke 2000 oxidation and performanceincreased fat oxidation even with CHO loading (because of increased FFA release, uptake or oxidation, or increased reliance on intramuscular TG?? who knows), NO significant difference in time trial performance
Carey 2001high fat VS high carb 1wk, then pre exercise carb load (and CHO during exercise), 4h at 65% VO2peak
Carey 2001 resultsdifference in metabolism remained, no significant difference in time trial performance
What does Helge state about high fat diets?Training response may be impaired in less fit populations by high fat diets

Section 5

Question Answer
Burke and elite athetes21 elite race walkers, 3 groups of 9-10 athletes with 3 week diet intervention and intensified training, measured VO2 and performance
Burke and elite athletes resultsVO2 increased in high fat group at 20km and 50km race pace, HOWEVER high and periodised CHO groups improved after 3 weeks, but low CHO high fat group did not

Section 6

Question Answer
high fat low carb diets, do they increase performance?unlikely for most athletes, may benefit a very small group of ultra-endurance individuals
high fat diets and fat use/muscle glycogen usehigh fat diets increase fat use, spare muscle glycogen
training combined with high fat diet on high intensity performancereduces high intensity performance, likely due to changes in PDH complex activity