1. By Gareth Mathias, Louis Payne,
Louise Booth, Talitha Drennan, Liam
Eley & Jo Whitmarsh

2. What is fat?
Fat is made up of - Simple lipids - Compound lipids - Derived lipids
What are the main external sources of fat?
- Food
What are the sources of fat in the body?
- Adipose Tissue - Plasma - Muscle Tissue
What are the types of fatty acids?
- Saturated - Unsaturated - Polyunsaturated - Monounsaturated
Functions of fat?
- The function we are interested in is energy store!

3. • Divided into simple, compound and derived lipids.
• Simple lipids: used as the principle storage form in the body.
• Compound lipids: basic component of plasma membranes
• Derived lipids: create some types of hormones.
• 95% of fat is triglyceride
• Triglycerides are made up from 3 Fatty acids + Glycerol
• They cannot move freely through cell membranes, and
require the enzyme: lipoprotein lipase.
• This breaks it down into smaller molecules, which can then be
used by the body.

4. • Triglycerides are the main form of fat storage in the body.
• Stored in white adipose-tissue cells, and some in liver and skeletal muscle.
• They are broken down into fatty acids by lipoprotein lipases and absorbed
from the blood into fat cells, muscle cells and liver cells.
• Fatty acids  fat molecules  fat droplets
• These take around 6 hours to digest and convert to a usable source of
energy.
• Adipose tissue is how the body stores metabolic energy for long periods of
time, perfect for endurance activities.

5. • A marathon consists of 26 miles and 385 yards. The average time for
males is 4 hours and 30 minutes, for females it is 5 hours and 10
minutes.
• Fat provides the main fuel source for long durations and low to
moderate intensity exercise (such as endurance sports, i.e. marathons).
• Although it takes longer to utilize fat stores, it is the largest energy
reserve for the body, providing more than carbohydrates and proteins.
• Fat is oxidised to supply ATP at exercises of about 60% of our VO2
max and below.
• At 25% of our vo2 max, almost all energy comes from fat.
• At 60% of our vo2 max, 50% of energy comes from fat.

6. Triacylglycerol
• Process of breaking down fats
so that free fatty acids (FFA) can Fatty Acids
be released into the circulation Diacylglycerol
for the working muscles.
Fatty Acids
• Triaglycerol  Fatty acids + Monoacylglycerol
Glycerol
Fatty Acids
• Broken down by enzyme Glycerol
hormone sensitive lipase (HSL).
• Glycerol to liver for glycolysis.
Blood
• Fatty acids + albumin or FFA go
Fatty Acids Liver
to muscle. Free Fatty
+ Albumin
Acids

7. Fatty acyl CoA (16C)
• Occurs in
mitochondria. Enoyl CoA
• Sequential removal
of 2C units from fatty Hydroxyacyl CoA
acid chain to form
Acetyl CoA. Ketoacyl CoA
• Acetyl CoA enters
Fatty acyl CoA (-2C) + Acetyl CoA
the TCA cycle.
+ Acetyl CoA
+ Acetyl CoA
TCA Cycle

8. •Acetyl CoA to CO2 and H2O in a cyclic pathway –
the TCA cycle.
•Takes place in mitochondria.
•One cycle = 1 molecule ATP, 3 molecules NADH, 1
molecule FADH2 formed.
•Generate hydrogen atoms for their subsequent
passage into the electron transport chain.
•ETC: Linked carrier molecules that remove
electrons from hydrogen (from NADH and NADH2)
and pass them to molecular oxygen.
•Specific carriers located on inner mitochondrial
membrane.
•Oxidative Phosphorylation: The process by which
ATP is synthesised during the ETC.
•A proton motive force drives ATP synthesis.
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hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sit
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9. • Fat is slow to digest and be converted into a usable form of energy (it can take up to
6 hours).
• Converting stored body fat into energy takes time. The body needs to breakdown fat
and transport it to the working muscles before it can be used as energy.
• Converting stored body fat into energy takes a great deal of oxygen, so exercise
intensity must decrease for this process to occur.
• With a marathon, fat can be used as a predominant energy source to help maintain
the intensity and level of the endurance event.

10. • Maughan, R.J et al. (2004) Food, Nutrition and Sports Performance 2:The
International Olympic Committee Consensus on Sports Nutrition. Routledge. New
York.
• Ryan, M. (2002) Sports nutrition for endurance athletes. VeloPress. Colorado.
• Maughan , R.J et al. (1997) Biochemisty of Exercise & Training. Oxford University
Press. Oxford.
• Bender, D.A. (2002) Introduction to Nutrition and Metabolism. 3rd ed. Taylor &
Francis. London.
• Jeukendrup, A.E et al. (1998) ‘Fat Metabolism During Exercise: A Review – Part 2:
Regulation of Metabolism and the Effects of Training’. Int. J. Sports Med, pp.293 –
302.
• http://www.talk-athletics.co.uk/guides/london_marathon.html
• http://sportsmedicine.about.com/od/sportsnutrition/a/Fat.htm