chap 6 (fat) Flashcards
which one between long or short fatty acid chain is more hydrophobic
long
fat that are solid at room temperature tend to be more saturated or unsaturated
saturated
predominant fats in food and fluid and what is it made off
triglycerides-> 3 FA + 1 glycerol
number of carbon in a FA chains are even or odd ? why
even because carbon are add 2 at a time
difference between saturated and unsaturated fatty acid
sat: no double bound between carbon
the cis form allow fatty acid to
bend
what does cis and trans mean
cis: group that are on the same side of double bond
trans: group that are on the other side
the terminal carbon is referred to as
omega
what are the two essential 18-carbon fatty aids that must be consumed in the diet
linoleic (omega 6) and alpha-linolenic (omega 3)
name some linoleic
¡ Sunflower oil
¡ Safflower oil
¡ Corn oil
¡ Soy oil
¡ Peanut oil
name some alpha-linolenic
¡ Dark green leafy vegetables
¡ Flaxseeds
¡ Soybeans
¡ Walnuts
¡ Canola oil
¡ Seafood
function of lipids
¡ Energy
¡ Cushioning
¡ Transport of fat-soluble vitamins
¡ Cell membranes
¡ Precursor for bile
¡ Precursor for hormones
¡ Formation of eicosanoids
¡ Taste and texture of food
what is the name of FA that have 20 carbons
eicosanoids
role of omega 3 fatty acids in recovery from strenuous exercise
blood vessel dilation, reduce inflammation, reduce blood clotting
which lipid can be use as fuel
fatty acid, triglycerides
cholesterol is mostly synthesized where
liver
The process of fat digestion begins in the _ and continues in the _to a small degree, but digestion of fat occurs predominantly in the _
mouth, stomach, small intestine,
undigested fat in the stomach has which effect
- delays emptying of the stomach
- feeling of fullness
fat must be exposed to what before crossing the membrane of the intestinal cell and why
biles salt and digestive enzyme because they don’t mix well with water
what is an important digestive enzyme help break down large FA to smaller
pancreatic lipase
role of lipoprotein + exemple
transport fat throughout the body -> chylomicron
which tissue play an important role in fat metabolism
adipose, muscle, liver tissue
fat that are digested and absorbed are stored in the body in the form of _ and what are the storages site
triglycerides, adipose tissue, liver, muscle and small degree in the blood
fat is metabolized where for energy
in mitochondria
Triglycerides stored in
adipocytes are broken down into the component parts glycerol and the fatty acid chains -> this catalyze by which hormone
hormone sensitive lipase
HSL is inhinbited by
insulin
mobilization of stored fat is inhibited _ have been consumed when _is elevated, and it is encouraged during the _ state (the period
from approximately 3 to 4 hours _eating until food is eaten again), fasting, starvation, and when stressed.
after meal, insulin, postabsorptative , after
HSL is stimulated by
epineprhine, norepinephrine, GH, TSH, cortisol
Each acetyl CoA that is derived from a
fatty acid chain can be oxidized to eventually form _ ATP
10
what is a limiting step of fatty acid metabolized
translocation
which cell have an increased capacity to take up and metabolized fat
Cells that have a large number of well-
developed mitochondria, such as slow-twitch muscle
fibers,
athlete with what have an increased ability to metabolized fat
attente with a genetic disposition for a greater number of slow-twitch muscle fiber
The normal blood ketone concentration is
less than
0.05 mmol/L
Ketone production is increased when fatty acid oxidation is _.
accelerated -> during fasting or starvation
what is the difference between ketosis and ketoacidosis
ketosis: elevated ketone bodies
ketoacidosis: prolonged excess of ketone bodies that overwhelms normal compensatory mechanism (decrease blood pH) -> pH in blood is more acidic than the body tissues
healthy individual have a normal ketone bodies of
< 3 mg/dL
advantage of fat supply during exercise
¡ Abundant in food supply
¡ Energy dense
¡ Substantial storage in adipose tissue
¡ Produces large amount of ATP
désavantage of fat use during exercise
require oxygen, several step so slow process
As exercise intensity _ (as a percentage of V ˙ O2max), the
percentage of energy provided by fat metabolism _, and
the percentage of energy from carbohydrate metabolism _.
increase, decrease, increase
what is the recommended fat-burning zone
lower-intensity aerobic exercise -> people burn more fat at lower intensity
why does fat oxidation decrease as intensity increase
increase anaerobic energy prod, lactate prevent FFA binding albumin , increase blood flow to muscle
T/F Long-term consumption of a diet that is high in fatwill result in a metabolic adaptation to favor fat oxidation at rest and during exercise of certain intensities.
t
what are the body adaptation to endurance exercise that allow fat mobilization
- FA mobilized from tissue more easily
- increase in capillary network
- increase in mitochondrial mass
effect of caffein on fat usage
caffeine may enhance free fatty acid mobilization during endurance exercise
the benefit of caffeine on fat usage is likely due to
its role as a central nervous system stimulant, resulting in a heightened sense of awareness and a decreased perception of effort
The appropriate amount of dietary fat for the athlete will depend on two factors
overall energy (caloric) need and macronutrient balance.
total daily fat intake
20-35% total caloric intake -> 1.0 g/kg/bw
effect of inadequate fat intake
Inadequate replenishment of intramuscular fat stores
¡ Inability to manufacture sex-related hormones
¡ Decline in high-density lipoprotein cholesterol (HDL-C)
¡ Inadequate fat-soluble vitamin intakes
WAYS TO LOWER DIETARY FAT
¡ Reduce portion size
¡ Prepare foods with less fat
¡ Add less fat to foods
¡ Order carefully at restaurants
¡ Be aware of “hidden fats”
¡ Lower-fat cuts of meat or poultry
¡ Low-fat or nonfat dairy products, and lower-fat versions of high-
fat processed foods
¡ Substitute fruits and vegetables for fat-containing snack foods
why do people may take medium chain triglyceride (MCTS)
supplies energy, reduce muscle glycogen, breakdown and improve performance
carateristic of MCTS
- 8-10C, easily digested, readily absorbed & oxidized rapidly
- burned, not store
max amount of MCTS tolerable
30g
claim of fish oil
increase vo2 max, improve membrane characteristic and function
caffein claims
improve performance in high intensity activities lasting 1-20min, delay fatigue,
T/F caffein increase fat oxidation
false
does of caffein supplement
5-6 mg/kg
what do you need to have if you want to increase carnitine
insulin
is there a scientific evidence that carnitine supplement alter fat metabolism or improve performance
no
Which of the following is an essential fatty
acid, one that cannot be manufactured in the body?
a. linoleic acid
b. palmitic acid
c. lactic acid
d. pantothenic acid
a
Most long-chain fatty acids are absorbed
from the intestinal mucosal cells in what form?
a. monoglycerides
b. triglycerides
c. chylomicrons
d. micelles
c
What is the enzyme found on the surface of
blood vessels that catalyzes the release of fatty acids
so they can be absorbed by fat and muscle tissue?
lipoprotein
The human body normally stores approxi-
mately how much energy as fat
a. 100 kilocalories
b. 1,000 kilocalories
c. 10,000 kilocalories
d. 100,000 kilocalories
d
A deficiency of carnitine in the body would
result in fat metabolism decreasing for which of the following reasons?
a. Triglycerides in fat cells could not be broken
down.
b. Fatty acids would not be transported properly
in the blood.
c. Fatty acids would not be transported properly
into mitochondria.
d. Beta-oxidation would be reduced.
c
When the body is stressed by exercise, fat
stored in adipocytes is:
mobilized
Which of the following is not true about fat
metabolism?
a. A person “burns” more fat as a percentage of total energy expenditure at rest.
b. As exercise intensity increases, the percentage of energy from fat decreases.
c. As exercise intensity increases, the total (absolute) amount of fat used for energy increases,
reaches a peak, and then decreases.
d. To “burn” more fat in a fixed period of time, a person should exercise at a low, “fat-burning”
intensity.
d
Which of the following statements about an
athlete’s dietary fat intake is true?
a. Athletes should always eat less than 30 percent
of their caloric intake from fat.
b. Athletes should determine carbohydrate and protein needs first, and then determine fat intake needs to maintain energy balance.
c. Low-fat diets will ensure a low percentage of
body fat.
d. As long as carbohydrate and protein needs are met, athletes do not need to pay attention to their fat intake.
b
What are the adverse consequences of inad-
equate fat intake?
a. inadequate fat-soluble vitamin intake
b. inability to produce sex-related hormones
c. inadequate replacement of intramuscular
triglycerides
d. all of the above
d
The appropriate amount of fat for training
and performance depends on:
overall energy need and macronutrients
Why would an endurance athlete limit the
amount of fat in a precompetition meal?
a. contributes to faster dehydration
b. delays gastric emptying
c. slows the metabolism of carbohydrate
d. all of the above
b
The mechanism by which caffeine most
likely improves endurance performance is that it:
a. spares muscle glycogen.
b. enhances the release of muscle and liver glycogen.
c. increases the oxidation of fatty acids during
exercise.
d. decreases perception of exertion.
d
Why do athletes consume medium chain
triglycerides (MCT) as a dietary supplement?
a. They are essential fatty acids that cannot be
manufactured in the body.
b. They add flavor and satiety to meals.
c. They are easily and quickly digested and ab-
sorbed compared to other fatty acids.
d. They reduce the risk of cardiovascular disease
c
