1.
NUTRITION FOR SPORT
AND EXERCISE
NDD30503
ASSOC PROF. DR. SHARIFAH WAJIHAH WAFA BTE SST WAFA
sharifahwajihah@uniza.edu.my

2.
Fats
Lecture 5

3.
Oils contain heart
healthy fatty acids

4.
1. Explain ketosis and the effect it may have on
training
2. Describe how the body uses fat to fuel
exercise
3. State fat recommendations for athletes and
calculate the amount of fat needed daily
4. Identify sources of dietary fat and assess an
athlete’s dietary fat intake
5. Evaluate dietary supplements related to fat
metabolism
Learning Objectives

5.
Introduction to Fats
 The word “fat” has many different meanings
 Primary source of energy at rest and during low-
intensity exercise
 Fat required in diet to provide essential fatty
acids that body cannot manufacture and for
absorption of fat-soluble vitamins
 Most concentrated source of energy – 9 kcals/g
 Fats are distinguished by their chemistry
 Certain fats in food and in the blood are
associated with cardiovascular disease

6.
Fatty Acids (FAs)
 FAs are chains of carbon and hydrogen
ending with a carboxyl group (COOH)
• Carboxyl group = a carbon with a double
bond to oxygen and a single bond to
oxygen/hydrogen

7.
FATTY ACIDS, SREROLS AND
PHOSPHOLIPIDS

8.
Fatty Acids (FAs)
 Chain length varies from 4 to 24 carbons
(even numbers only)
• 2 carbons are added at a time
 Double bonds are a distinguishing factor
 Fatty acid series is a distinguishing factor
 Most FAs used in human metabolism have
16-18 carbons

9.
Oleic Acid – 18 carbons
Cis double bond

10.
Fatty Acids (FAs)
 Saturated fatty acids have no
double bonds between carbons
• Saturated = no additional
hydrogen atoms can be
incorporated
• Mostly found in animal
products
• Also plant oils – palm oil,
coconut oil
Used in cookies, cakes,
donuts, pies
• Ex/ palmitic acid, stearic
acid, myristic acid

11.
Fatty Acids (FAs)
 Unsaturated fatty acids contain one or
more double bonds between carbons
 16-22 carbons and 1-6 double bonds
• Monounsaturated fatty acid – only one
double bond
Ex/ oleic acid
• Polyunsaturated fatty acid – 2 or more
double bonds
Ex/ linoleic acid, arachidonic acid

12.
Saturated, Monounsaturated, and
Polyunsaturated Fatty Acids

13.
Vegetable oils are excellent sources of
monounsaturated and polyunsaturated fatty acids.

14.
It is important to know the amounts and types of
dietary fats found in foods.

15.
Cis and Trans Formations
 Cis refers to groups on the same side of double
bond between carbons
• Most unsaturated fats are cis
• Bend in the chain
 Trans refers to groups on opposite sides of
double bonds between carbons
• Straight chain
• Produced synthetically through addition of hydrogen
atoms to unsaturated fatty acid
Hydrogenation process – used in commercial food
processing to make liquid oils more solid

16.
Fatty Acid cis and trans Formations

17.
Trans Fats
 Hydrogenation of vegetable oils gives products
desirable texture and longer shelf life
 However, this produces trans fats – which are
associated with increased risk for CVD
• Increase LDL
 American Heart Association (AHA) recommends no
more than 1% of total kcals intake from trans fats –
“intake should be as low as possible”
 Read labels and check ingredient lists
 Conjugated Linoleic Acid (CLA) – naturally occurring
trans fat that may have some health benefits

18.
Omega-3, -6, and -9 Fatty Acids
 Polyunsaturated fats can be classified by placement of
first double bond counted from last carbon on chain
farthest from carboxyl group
• Omega-3
Alpha-linoleic acid (ALA)
Eicosapentanoic acid (EPA)
Docosahexaenoic acid (DHA)
• Omega-6
Linoleic acid
Arachidonic acid
• Omega-9
Oleic acid

19.
Omega-3, -6, and -9 Fatty Acids

20.
3 Major Lipids
 3 major types of lipids in human nutrition:
1. Triglycerides
3 FA’s attached to glycerol
95% of fat found in foods are triglycerides
2. Sterols
Ex/ cholesterol
3. Phospholipids
Phosphate-containing fats

21.
Triglycerides (TG, Trig)
 Composed of 3 fatty acids and one glycerol
 TGs are the predominant fat in food and in body
 Usually contains a combination of different FAs

22.
Triglycerides (TG, Trig)
 “Triacylglycerol” is correct technical term
 Triglycerides found in food contain a combination
of saturated, monounsaturated, and
polyunsaturated fatty acids
• Foods are grouped according to predominant FA
 Ex/ coconut oil classified as saturated fat since it is
92% saturated fat, 6% MUFA and 2% PUFA

23.
Structure of Triglycerides

24.
Fatty Acid Distribution in Selected Foods

25.
Essential Fatty Acids
 Two 18-carbon fatty acids are essential FA’s
 The body cannot manufacture these, so
they must be consumed in the diet
 Widely found in foods
• Alpha-linolenic acid (omega-3) – soy, canola,
and flaxseed oils, green leafy vegetables, fatty
fish and fish oils
• Linoleic acid (omega-6) – soy, safflower, and
sunflower oils

26.
Omega-3, -6, and -9 Fatty Acids
 Omega-3 fatty acids
• i.e alpha-linolenic acid (ALA), EPA, DHA
• Body can convert ALA to EPA and DHA, but amount is
limited
• Deep water, oily fish
• Fish oil supplements
• Flaxseed, green leafy vegetables, nuts
• Soybean and canola oil

27.
Omega-3, -6, and -9 Fatty Acids
 Omega-6 fatty acids
• i.e linoleic acid (vegetable oils), arachidonic acid
(animal fats)
• Eicosanoids = fatty acids w/ 20 carbons
• Eicosanoids made from arachidonic acid are
associated w/ CVD, diabetes, HTN, obesity
• Omega-3 and omega-6 in competition for same
enzymes
• Optimal ratio 4:1 or less of omega 6:omega 3
• Typical Western diet = 15:1 or more

28.
Omega-3, -6, and -9 Fatty Acids
 Omega-9 fatty acid
• i.e oleic acid
• Olive oil
• Decreased CVD risk if it replaces saturated
and trans fatty acids in the diet

29.
Sterols
 4 ring structure known as
“steroid”
 One or more hydroxyl (OH)
groups attached and no carbonyl
(=C=O) or carboxyl (COOH)
groups
 i.e cholesterol, vitamin D, sex
hormones, cortisol
 Cholesterol
• Only found in animal foods in which
fat has not been removed
• Important part of cell membranes
• Also manufactured in the body by liver

30.
Structure of Sterols

31.
Phospholipids
 Similar in structure to
triglycerides
 Contain phosphate
 Structural component of cell
membranes
 i.e Lecithin
• Found in soybeans, eggs,
milk
• Often used as an
emulsifier such as in
nonstick cooking spray

32.
Type of fat consumed can influence CVD
 Beneficial for prevention of heart disease
(CVD):
1. Monounsaturated fatty acids
2. Polyunsaturated fatty acids
3. Omega-3 fatty acids

33.
Type of fat consumed can influence CVD
 Recommended that trans fat consumption be
as low as possible due to increased risk of
CVD
• <1% of total kcals (AHA)
 Excessive saturated fats and cholesterol can
increase risk of CVD
• <7% saturated fat/day (AHA)
• <300 mg cholesterol/day; <200 mg if CVD
(AHA)

34.
DIGESTION, ABSORPTION AND
TRANSPORTATION OF FATS

35.
Fats and Performance and Health
 From a performance perspective…
• Fat should provide 25-35% of total kcals/day
(AHA) – lower than 20% can be detrimental
• Fat provides energy at rest and during low-
intensity exercise
• Amount of fat intake for athlete will depend on:
1. Overall energy need (total kcals)
2. Macronutrient balance (pro, CHO, fat)

36.
Digestion of Fats
 Fats are large, insoluble molecules that must
be bound to protein for transport in blood
 Fat is primarily digested in the small intestine
 Bile salts help to start breaking down fats
 Pancreatic lipase is important digestive
enzyme
• Secreted by pancreas into the small intestine
and helps to break down large fat molecules into
smaller components
Diglycerides, monoglycerides, free fatty acids

37.
Digestion of Fats
Fats are digested in two stages:
Firstly, bile (released by the gall bladder) allows
the fat to “mix” with water by breaking the fat into
smaller droplets. This is called emulsification.
bile
Secondly, the digestive enzyme lipase breaks
each fat molecule into the smaller glycerol fatty
acid molecules .

38.
Digestion of Fats
• Secondly, the digestive enzyme lipase breaks
each fat molecule into the smaller glycerol fatty
acid molecules .
Lipase +
fat molecule glycerol fatty acids

39.
Digestion of Fats
 Undigested fat in the stomach can:
1. Delay gastric emptying
Athletes may limit fat intake when they do not
want gastric emptying delayed, such as during
endurance event when rapid movement of
CHO-containing fluids into intestine is
beneficial
2. Cause feeling of satiety
Athletes may include fat-containing foods
when they want to avoid feeling hungry for several
hours

40.
Absorption of Fats
 Fat particles enter mucosal cells
via passive diffusion (high to
low concentration)
 Majority are re-assembled into
TGs
• 12-18 carbon fatty acids
• TG are incorporated into
chylomicrons
 Chylomicrons (lipoprotein) are
large protein and fat molecules that
help transport fat throughout body
 Short (4 carbons) and medium
chain fatty acids (6-10 carbons)
pass through mucosal cells
unchanged

41.
Transportation of Fats
 Blood
• Water, RBCs, WBCs, oxygen, nutrients, electrolytes
• Enters tissues via arteries and leaves via veins
• Circulates within tissues via capillaries
• Some components of blood are filtered out of
capillaries as interstitial fluid
 Lymph
• Part of the blood that is not filtered out of capillaries
for use by tissues
• WBCs, proteins, fats
• Moves through lymphatic system

42.
Transportation of Fats
 Chylomicrons are slowly released into lymph
 Short and medium chain fatty acids are released into
blood via the portal vein where they will be bound to a
protein
• Albumin is most common transport protein for fat

43.
Transportation of Fats
 Blood lipid levels are increased for several hours
after fat consumption; highest ~3 hrs
 TG portion of the chylomicron can be absorbed
by adipocytes and muscle cells
• Lipoprotein lipase (LPL) stimulates the release of
FAs from TGs
• FAs then rapidly absorbed by fat and muscle cells

44.
METABOLISM OF FATS

45.
Metabolism of Fats
 Fat can be easily stored in the body
• Esterification is the process of TG formation
from glycerol molecule and 3 FAs
• Insulin stimulates lipoprotein lipase activity
• LPL breaks down circulating TGs from lipoprotein,
feeing FFAs for uptake into fat cells
• Once taken up into adipocytes, FAs are re-assembled
into TGs for storage
• Fats are stored in the body largely in form of TGs

46.
 Main sites of fat storage:
1. Adipose tissue
Subcutaneous fat – just
beneath skin
Visceral fat – surrounding
internal organs
2. Liver
3. Muscle
Intramuscular triglycerides
• i,.e Heart muscle, slow
twitch muscle fiber
4. Blood – small amount
Visceral fat
Metabolism of Fats

47.
Metabolism of Fats
 Advantages of fat storage
• Contain twice the amount of kcals per unit than CHO
and protein
9 kcal/g
• Normal amount of energy stored as fat = 100,000
kcals (500 g of CHO (2000kcal) in the form of muscle glycogen,
liver glycogen and blood glucose)
• “Energy dense” nutrient
• Anhydrous (no water associated with it) (when CHO is
stored in the form of glycogen, ~ 2 g of water are stored along
with every g of glycogen, increasing the weight without
increasing the energy content)

48.
Metabolism of Fats
 Fat is an important source of energy for many
athletes
 However, process of metabolizing fat is complex
and slow…
1. Fats must be mobilized from storage
2. Transported to appropriate tissues
3. Taken up into tissues
4. Translocated and taken up by mitochondria and
oxidized via Krebs cycle
5. At steady state exercise, it takes ~10-20 minutes for
fat oxidation to reach its maximal rate of activity

49.
Metabolism of Fats
 In order for fat to be used as energy, TGs stored
as fat in adipocytes must be broken down via
lipolysis → glycerol + 3 FAs
 Lipolysis is catalyzed by HSL
• Hormone Sensitive Lipase (HSL) = enzyme
found in adipocytes that helps to mobilize fat
• Stimulated by catecholamines, growth hormone,
glucocorticoids, thyroid-stimulating hormone.
• Inhibited by insulin – so, mobilization of stored fat
is inhibited after meals

50.
Metabolism of Fats
 Mobilizing fat from storage is best 3-4 hours after
eating (post-absorptive), fasting, starvation, and when
stressed (including exercise)
 After lipolysis…
• FFAs and glycerol circulate in the blood
• Glycerol carried in blood to liver where it can be
converted to glucose or re-assembled into
triglycerides
• FFAs attach to protein (albumin) and are distributed
to other tissues in body for metabolism

51.
Mobilization and Transportation of Stored
Triglyceride

52.
Metabolism of Fats
 1 ATP used along with CoA to convert FA chain
to fatty acyl-CoA in the outer mitochondrial
membrane
 Then fatty acyl-CoA must be transported into
mitochondria where it undergoes beta-
oxidation via carnitine transport mechanism
• Carnitine – synthesized from AAs lysine and
methionine and is required for transport of
fatty acids

53.
Metabolism of Fats
 Beta oxidation involves 4 chemical steps during
which 2 carbon segments are cleaved off the FA
chain and converted to acetyl CoA, which can
then enter Krebs cycle
• Each acetyl CoA derived from a FA chain can be
oxidized to eventually form 12 ATP

54.
Ketosis
 Acetyl CoA can be catabolised to produce ketone
bodies:
• Acetoacetate
• Beta-hydroxybutyrate
• Acetone
 “Overflow” pathway
 The liver can produce up to 185 g ketones/day
• Ketones supply ~2-6% of body’s energy needs after
overnight fast
 Normal blood ketone concentration: < 0.05 mmol/L
 Normal urine ketone concentration is zero

55.
Ketosis
 Ketosis is an abnormal increase in ketone
bodies or a blood ketone concentration of >0.06
mmol/L
 Occurs when fatty acid oxidation is accelerated
due to:
• Low CHO intake due to starvation state (self-
restriction or involuntary)
• Impaired CHO metabolism (diabetes)
Dangerous, can result in ketoacidosis = pH of
blood more acidic than tissue and can result in
coma, death

56.
Ketosis – How are ketones formed?
 Normally w/ an adequate CHO intake…
• Glycolysis converts glucose to pyruvate
• Pyruvate transported to mitochondria where it
is metabolized to acetyl CoA
• Acetyl CoA joins with oxaloacetate in the 1st
step of the Krebs cycle

57.
Ketosis – How are ketones formed?
 But, with a low CHO diet…
• Body must find other sources of acetyl CoA –
fatty acids and some amino acids
• As more FAs are broken down to provide
acetyl CoA, supply of oxaloacetate decreases
• Acetyl CoA accumulates and ketone bodies
are produced

58.
Ketosis
 2-3 days of low CHO intake…
• Body can produce glucose from other sources
– lactate, amino acids
• 2/3 fuel used by brain is glucose; 1/3 ketones

59.
Ketosis
 After a few days of low CHO intake… starvation
• Muscle glycogen depleted with no resynthesis
• Loss of some skeletal muscle
• Glucose will be primarily made from glycerol
(obtained via lipolysis)
• Ketones will be primary fuel source for brain
• Weight (fat) loss

60.
Ketosis
 Low CHO, calorie-restricted diet is popular
method for weight loss
 Not likely to be beneficial for athletic
performance – likely will have a negative effect
on training and performance
• Muscle loss
• Depletion of glycogen
 Clinical uses of ketosis include:
• Supervised weight loss for overweight/obese
• Supervised ketogenic diet for seizure control

61.
Ketosis

62.
KEY POINTS
1. Fats are stored as TG formed from a glycerol
and 3 FAs
2. Fat is energy dense, containing 9kcal/g
3. In order to be used, fats must be translocated,
or broken down from their storage and
transported to the site of usage
4. In order to metabolised aerobically, FAs must
be converted to fatty acyl-CoA, transported into
the mitochondria, and converted to acetyl CoA
via -oxidation

63.
KEY POINTS
5. Fats are more readily metabolised by tissue
with a higher aerobic capacity
6. Ketone bodies can be produced as a result of
fat metabolism and overreliance on fat
metabolism can result in ketosis

64.
FATS AS A SOURCE OF ENERGY
DURING EXERCISE

65.
Fats as an Energy Source During
Exercise
 Primary source of energy at rest and
during low-intensity exercise
 Advantages
• Fat is abundant in food supply
• Energy dense
• Stored in substantial amounts in adipose
tissue
• Produces large amount of ATP

66.
Fats as an Energy Source During
Exercise
 Disadvantages
• Takes time to transport and metabolize (many
steps)
• Requires oxygen so it can only be used in
aerobic metabolism
Limited to activities that use oxidative
phosphorylation

67.
Energy expenditure and fuel utilization during running can be
measured through indirect calorimetry and RER.
It is important to know the relative (percentage) and
absolute amount of fat utilised as a fuel

68.
Relative and Absolute Fat Oxidation
 Respiratory Exchange Ratio (RER) is the ratio
of CO2 produced to the amount of O2 consumed
 RER is 1.0 during CHO metabolism
 RER is 0.70 during fat metabolism
• “Relative”
Percentage of energy derived from CHO or fat
• “Absolute”
Total amount of energy expended (kcal/min)
• If we know relative and absolute energy
expenditure, we can determine caloric
expenditure (kcal/min) from fat and CHO

69.
Energy Expenditure and Fuel Utilization
 Case Study –
• 49 yr old male training for first marathon
• Some previous recreational running experience
• 168cm and 82.5 kg

70.
Energy Expenditure and Fuel Utilization
 The RER increases with each successive
increase in exercise intensity
 As RER increases, the % of energy supplied by
fat metabolism declines
 “Crossover concept” – the point in exercise
intensity when CHO increases and becomes
predominant source of energy and the utilization
of fat declines to a lesser percentage

71.
Figure 6-15 p214

72.
Energy Expenditure and Fuel Utilization
 Case Study –
• 49 yr old male training for first marathon
• Some previous recreational running experience
• 168cm and 82.5 kg

73.
Figure 6-16 p215

74.
 If fat is such a good energy source, why does fat
metabolism decline as exercise intensity
increases?
• Lower intensity exercise, increase in fat oxidation
• As exercise intensity continues to increase, there
is increase reliance on fast-twitch muscle fibers
• rely on more on anaerobic energy systems
• poor ability to oxidise fat
• Use anaerobic glycolysis, they produce lactate
• Lactate inhibit plasma protein albumin to bind and
carry FFAs in the blood
Energy Expenditure and Fuel Utilization

75.
Energy Expenditure and Fuel Utilization
 Fat oxidation during prolonged steady state
exercise
• Prolonged period of time lead to muscle
glycogen depleted
• Rely more on fat oxidation
• Gradual decline in RER

76.
Figure 6-17 p216

77.
 Do You Have to Burn Fat to Lose Fat?
• Low-intensity aerobic exercise (“fat-burning
zone”)
• RER is lower during lower intensity exercise
• % of energy derived from fat is high
• Total amount of energy expended is lower
Energy Expenditure and Fuel Utilization

78.
Energy Expenditure and Fuel Utilization
 Case Study –
• 49 yr old male training for first marathon
• Some previous recreational running experience
• 168cm and 82.5 kg

79.
Energy Expenditure and Fuel Utilization
 Most important factor in weight and fat loss is
total caloric expenditure, not exercise intensity or
the source of fuel used during exercise
918 kcal
804 kcal 300 kcal
250 kcal

80.
 Do You Have to Burn Fat to Lose Fat?
• Not necessary to burn fat during exercise
to lose body fat
• Total energy expended is more important
than % expended from fat
Energy Expenditure and Fuel Utilization

81.
Effects of Training on Fat Usage
 General adaptations
• Endurance training results in an enhanced
ability to oxidize fat
• FAs are more easily mobilized from adipocytes
• Advantageous for endurance athletes – can rely
more on fat metabolism and spare glycogen for
later in the race

82.
KEY POINTS
1. Fat utilisation can be determined by the
respiratory exchange ratio (RER), which is the
ratio of CO2 produced to oxygen consumed.
2. The % of energy derived from fat metabolism
decreases as activity and exercise intensity
increases.
3. As exercise intensity increases, the total
amount of energy derived from fat metabolism
increases, reaches a peak, and then begins to
decrease.

83.
KEY POINTS
4. If exercise continues at the same intensity for long
periods of time, the relative amount of energy derived
from fat metabolism increases slightly (if the athlete
does not consume any CHO during exercise)
5. Regular aerobic exercise training increases the body’s
ability to metabolise fat, particularly during exercise at
the same absolute exercise intensity.
6. Increasing the amount of fat in the diet increases
reliance on fat as an energy source at rest and during
lower intensities of exercise, but does not result in
improved performance at higher exercise intensities

84.
FAT RECOMMENDATIONS FOR
ATHLETES

85.
Fat Recommendations for Athletes
 Total daily fat intake depends on total
energy, CHO and protein intake.
1. Total energy (kcals) needed
2. Macronutrient balance
Higher CHO/protein intake typically means
lower fat intake
Severe restriction of fat intake not
recommended

86.
Fat Recommendations for Athletes
 Often expressed as a % of total energy
intake
• 20 to 35% total caloric intake
 May be expressed on g/kg body weight
basis
• ~1.0 g/kg daily is general guideline
• May need to be as high as 2.0 g/kg for
endurance athletes or 3.0 g/kg for
ultraendurance athletes

87.
Misconceptions of Fat
 Fat is perceived negatively by society and fat
intake is often restricted
 People believe that a high fat intake results in
increased body fat
 However, increases in body fat are due to the
excess consumption of total energy (kcals)
 Overconsumption of any of the macronutrients
(fat, CHO, protein, alcohol) can result in
increased body fat
 Some athletes have a “fat phobia” or believe fat
to be forbidden

88.
Fat Recommendations for Athletes
 Reducing caloric intake by reducing dietary fat
intake over several weeks or months may help
athletes a loss of body fat.
• Reducing body fat may result in improved performance
i.e low % body weight for a runner is beneficial
because it is less weight to be moved
• Fat intake is typically reduced since reductions to CHO
or protein intakes may be detrimental to performance
• Athletes may consume a short-term, low fat diet to
achieve body composition goals

89.
Fat Recommendations for Athletes
 Inadequate fat intake can negatively affect
training, performance and health.
1. Inadequate replenishment of intramuscular fat
stores (muscle triglycerides)
2. Inability to manufacture sex-related hormones
Testosterone, estrogen
3. Alteration in the ratio of HDL:LDL
Decline in HDL
4. Inadequate fat-soluble vitamin intakes
When <0.75 g/kg fat intake
5. Essential fatty acid deficiencies
Linoleic and alpha-linolenic

90.
KEY POINTS
1. To determine the appropriate fat intake, the athlete
must consider total caloric, CHO and protein intakes.
2. Some athlete consume too much fat relative to the
amount of CHO and protein needed. They need to
slightly increase CHO and protein intakes and reduce
fat intake to a degree.
3. Some athletes chronically consume too little dietary fat
as part of a semi starvation diet, and training,
performance, and health may suffer.
4. If done appropriately, reducing fat intake can be an
effective strategy for body fat loss.

91.
TRANSLATING DAILY FATS
RECOMMENDATIONS TO FOOD
CHOICES

92.
Translating daily fats recommendations
to food choices
 Amount and types of fats in food
• Predominately saturated: (<7% total
kcals/day)
• Hard (stick) margarine
• Butter
• Cream
• Coconut oil

93.
Translating daily fats recommendations
to food choices
 Predominantly monounsaturated:
• Olive, canola, and peanut oils
• Some safflower oils
• Avocado
• Olives
• Nuts

94.
Translating daily fats recommendations
to food choices
 Predominantly polyunsaturated:
• Corn, soy, and flaxseed oils
• Some safflower oils
• Liquid and soft (tub) margarines
• Mayonnaise and some salad dressings
• Sunflower, pumpkin, and flax seeds

95.
Fats and Oils

96.
High Fat Foods

97.
Meat, Fish, Poultry and Dairy

98.
Snack Foods

99.
Fat Substitutes
 Some foods are made with fat substitutes
• Often made from CHO sources
• Many fat-free products do not have fewer kcals
than original product
• Olestra (Olean®)
• Fat substitute composed of sucrose polyester
• Cannot be absorbed due to its chemical structure
• May inhibit absorption of fat soluble vitamins
• Side effects – abdominal cramping, loose stools

100.
KEY POINTS
 The amount and types of fat in food varies
 Athletes often choose lower fat versions of food
 Many “fat-free” products are not low in calories

101.
FAT-RELATED DIETARY
SUPPLEMENTS

102.
Caffeine
 Caffeine is a central nervous stimulant that helps
to delay fatigue
 Dose: 2-3 mg/kg body weight for endurance
 Consensus opinion: caffeine may enhance FFA
mobilization during endurance exercise, but fat
oxidation is not significantly increased and
muscle glycogen is not spared

103.
Caffeine
 Evidence that caffeine can enhance
endurance performance
• Distance runners, cyclists, cross country skiers
 Also evidence that caffeine can improve
performance for those engaged in high
intensity activities lasting 1-20 min
• Runners, cyclists, swimmers, rowers
 Evidence for improving performance in
athletes in other sports has been inconclusive

104.
Caffeine
 Dose for endurance athlete: 2-3 mg/kg body
weight
 Caffeine takes 30-45 minutes to get into cells
 Half life of caffeine is ~ 5 hours
 Caffeine has side effects:
• Increase in heart rate
• GI distress
• Interference with sleep
 Caffeine is addictive and sudden withdrawal can
result in severe headaches
 Trial and error

105.
Caffeine
 Caffeine can be consumed via:
• Pills – 1 tablet = 100 mg; 1 Excedrin = 65 mg
• Energy bars – 1 bar = 50-100 mg
• Energy shots – 2 oz = 200 mg
• Gels – 1 oz = 50 mg
• Energy drinks – 8 oz = 80 mg (Red Bull)
• Coffee – 8 oz = 85-90 mg
• Soda – 12 oz = 36 mg

106.
Caffeine
 Caffeine is a banned substance at certain
concentrations by some sports-governing bodies
• NCAA: post-competition >15 mcg/ml urine level
would disqualify
Equivalent to 6-8 cups of coffee 2-3 hours prior to
competition
• IOC: monitors caffeine levels, but does not
disqualify
 Caffeine intoxication is possible, but rare
 Caffeine not recommended for children or
adolescents (AAP, ACSM)

107.
Carnitine Supplements
 Carnitine is essential to transport
FA into mitochondria where they
are broken down for energy
 Found in food and synthesized
in the body from lysine
 Deficiencies are rare
 Supplement dose: 2 to 4 g/day
 Supplements seem to be safe at
such dosages

108.
Carnitine Supplements
 Studies show that carnitine supplements do
not increase carnitine content of muscles
 Carnitine may play role in increasing blood
flow to muscles, reducing oxidative stress
(Huang & Owen, 2013)
 No evidence of altered fat metabolism or
improved performance; however, no
evidence of detrimental performance
either

109.
Medium-chain Triglyceride Supplements
 MCTs contain 6-10 carbon atoms
 Rapidly absorbed via portal vein and
easily transported to mitochondria
 Studies show MCT ingestion does
not alter fat metabolism, spare
muscle glycogen or improve
performance (Hawley, 2002; Horowitz and Klein,
2000)

110.
Medium-chain Triglyceride Supplements
 May impair performance in some cases
• Negative side effects include GI upset
• (Goedecke et al., 2005) – found that ingestion of
MCT by ultraendurance cyclists compromised
sprint performance d/t GI upset

111.
Omega-3 Fatty Acids
 Marketed to athletes to reduce inflammation,
reduce effects of oxidative stress and
counteract immune dysfunction associated w/
strenuous exercise
 Recommended dose 1-2 g/day
• FDA recommends to not exceed 3 g/day
 Studies show omega-3 FA’s do not appear
to positively affect inflammation or
immune response or to positively affect
performance

112.
1. Fat is the most energy-dense nutrient found in
food
2. Fat is the primary energy source at rest and
during low-intensity activity
3. Caution should be used when restricting fat
because athletes can reduce the fat in their
diets too much
SUMMARY