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Sports Nutrition
Lesson 27
Fats: Ergogenic Aspects
Because Exercise training leads to an increased utilization of Fatty Acids as an
energy source and improved performance in prolonged endurance events, a
variety of practices have been employed in attempts to facilitate this metabolic
process during exercise.
In other words, what can be done to make
fat burning improve athletic performance?
Fats: Ergogenic Aspects
FAT LOADING
Dietary strategies designed to increase the supply or metabolism of fat as an
energy source during exercise may be called fat loading.
Fat loading can be done on an acute basis or chronic basis.
Acute - dietary strategies immediately before exercise.
Fats: Ergogenic Aspects
Acute Fat Loading
Because the rate at which FFA are oxidized in the muscle is dependent in part
upon their concentration in the blood plasma, several strategies have been tried in
an attempt to increase plasma FFA levels.
Lipid digestion and absorption are slow, so one strategy is to infuse a lipid solution
directly into the blood along with heparin.
Heparin is a substance that stimulates lipoprotein lipase activity and increases fat
oxidation. It also reduces CHO oxidation,
Fats: Ergogenic Aspects
A national team in the Tour de France used this practice. The entire team
withdrew from the race, allegedly due to a bad reaction.
No research supports
this ergogenic technique.
Fats: Ergogenic Aspects
Another strategy is to ingest a high-fat meal before exercise performance.
Research subjects consumed a high-fat meal, a high CHO meal, and a high
protein meal.
They performed a cycling test to exhaustion
at 78-80% VO2 max.
The meal composition had no clear effect
on performance.
Fat: Ergogenic Aspects
An acute high-fat diet does not seem to enhance performance and in fact may
actually impair performance if it contributes to gastrointestinal distress.
Research has shown that a high-fat diet
for 1-2 days may actually impair
performance in high-intensity exercise.
Fats: Ergogenic Aspects
CHRONIC HIGH-FAT DIETS
Researchers studied the effects of a long term high-fat diet. Athletes consumed
diets that were about 50% fat. (current recommendation is 30%)
Research has shown that when an individual is placed on a low-CHO and high-fat
diet for about a week or more, the body adjusts its metabolism to use fats more
efficiently .
However, some athletes respond to this diet and some don’t. Screening is
necessary to see if they athlete will or will not respond.
Fats: Ergogenic Aspects
Research has been done on chronic high-fat diets under a variety of
circumstances. Athletes in general showed increased fat metabolism.
Findings generally support the conclusion that chronic
high-fat diets for 1-2 weeks are not ergogenic for
endurance athletes.
Fats: Ergogenic Aspects
FASTING
Some research indicated that fasting for 24 hours may increase plasma FFA
availability. Does this work?
Fasting reduces muscle glycogen stores and Hypoglycemia.
Some research involved long term caloric restriction. (60% of maintenance)
Fasting for several days may impair CHO metabolism and is not a recommended
procedure for endurance athletes.
Fats: Ergogenic Aspects
Medium Chain Triglycerides can be absorbed directly by the liver without going
the chylomicron route. It was suggested that they could be available for use faster
because of the direct absorption.
MTC’s were studied under a variety of circumstances. MCT’s alone, CHO alone,
and MTC and CHO together. Review of these studies concludes that MTC
supplementation is ineffective in improving exercise performance.
Fats: Ergogenic Aspects
IS THE GLYCEROL PORTION OF TRIGLYCERIDES AN EFFECTIVE
ERGOGENIC AID?
As you know, glycerol is one of the by-products of triglyceride breakdown. This
glycerol can be oxidized during prolonged exercise, following conversion into
glucose in the liver.
The theory was that it could be an efficient energy source during exercise.
Did it work? No! The rate at which the liver converts glycerol to glucose is not
rapid enough to be an effective energy source.
Fats: Ergogenic Aspects
LECITHIN
Lecithin is a phospholipid that occurs naturally in a variety of foods like beans,
eggs and wheat germ. Because it is an important component of many types of
human body tissues, the theory is that it will be ergogenic in nature.
Studies have not shown that lecithin is an
effective ergogenic aid.
Fats: Ergogenic Aspects
PHOSPHATIDYLSERINE
Phosphatidylserine is a naturally occurring phospholipid found in cell membranes.
Foods that are good sources are green leafy vegetables, rice, fish and soybeans.
Phosphatidyl Serine is marketed as a dietary supplement said to improve brain
health.
Studies have not shown this supplement to be ergogenic.
Fats: Ergogenic Aspects
Omega-3’s
The theories -
One theory is based on findings that omega-3’s may be incorporated into the
membrane of the red blood cell making the RBC less viscous(sticky) and less
resistant to flow.
Another theory is based on the role of omega-3 by-products- eicosanoids.
Eicosanoids prostaglandin E and prostaglandin I.
Fats: Ergogenic Aspects
Eicosanoids
These 2 eicosanoids may cause a dilation of the blood vessels. The combination
of less viscous RBC’s and vasodilation should enhance blood flow, facilitating the
delivery of blood and oxygen to the muscles during exercise benefiting the
endurance athlete.
These prostaglandins may also stimulate the release of human growth hormone.
This might stimulate muscle growth and benefit the strength/power athlete and
may also help recovery from intense exercise bouts.
Fats: Ergogenic Aspects
The best selling book by Barry Sears “The Zone” suggests that certain fats in the
“zone” diet are of value to the athlete. The zone diet is based on the consumption
of 40% of calories from CHO, 30% from protein and 30% from fat.
There are companies that manufacture products based on the 40:30:30 ratio and
target them at the sports nutrition market. Sports bars containing omega-3’s are
one example.
Several reports in swimming magazines indicated that such a diet was responsible
for the success of the Stanford swim team. However the data was
anecdotal(stories) rather than scientific.
Fats: Ergogenic Aspects
Fats: Ergogenic Aspects
The bottom line on omega-3’s - There does not appear to be sufficient data to
support an ergogenic effect of omega-3’s.
Fats: Ergogenic Aspects
CARNITINE
Carnitine is a water-soluble vitamin like compound that facilitates the transport of
long-chain fatty acids into the mitochondria.
There are several forms of carnitine, and in this discussion carnitine will mean Lcarnitine.
Carnitine was discovered in 1905 and was considered to be an essential vitamin.
More recently is was conditionally labeled an amino acid.
Fats: Ergogenic Aspects
CARNITINE
While carnitine is an extremely important catalyst for metabolic reactions in the
muscle, carnitine is not an essential dietary nutrient because it may be formed in
the liver from other nutrients.
Carnitine is found in substantial amounts in animal foods so most individuals
consume a sufficient amount in the diet.
The theory is that carnitine can enhance physical performance because of several
of its metabolic functions in the muscle cell.
Fats: Ergogenic Aspects
The theory is that supplemental carnitine might facilitate the transport of LCFAs
into the mitochondria for oxidation, which would be an important consideration if
the oxidation of fatty acids was limited by their transport into the mitochondria.
Using the theory that carnitine supplementation will increase fatty acid oxidation,
manufacturers marketed it as a weight-loss supplement either alone or with
exercise to facilitate fat burning. The thinking is that loss of excess body fat could
provide a mechanical edge to some athletes.
Fats: Ergogenic Aspects
Fats: Ergogenic Aspects
CARNITINE
Another metabolic role of carnitine may be to facilitate the oxidation of pyruvate.
This could enhance the utilization of glucose and reduce the production of lactic
acid during exercise thus enhancing performance.
However, carnitine may expedite the oxidation of amino acids, leading to
premature fatigue.
Fats: Ergogenic Aspects
Carnitine supplementation has been used effectively to improve exercise
capability in patients with serious diseases.
Patients with peripheral vascular disease and heart and renal disease have shown
increased exercise capacity with carnitine supplementation.
.
Fat: Ergogenic Aspects
HYDROXYCITRATE
Hydroxycitric acid is derived from a tropical fruit and marketed as a dietary
supplement that will promote oxidation of fatty acids.
The available evidence indicates that HCA supplementation does not modify fat
utilization during exercise, much less confer an ergogenic effect.
Fats: Ergogenic Aspects
Fat: Ergogenic Aspects
CONJUGATED LINOLEIC ACID
CLA has been marketed as a sports dietary supplement to resistance trained
individuals, manly as a means to promote weight loss and to gain muscle mass.
For similar and other reasons it has been marketed as a means to promote health.
Based on current research, CLA does not appear to be an effective ergogenic aid.
Fats: Ergogenic Aspects
Conclusions:
- Endurance capacity is not systematically improved with increases in serum
FFA
- Individuals may find it difficult to adhere to a high-fat diet
- US Anti-Doping Agency stresses that no attempt should be made to consume
more fat.
- Carbohydrate is more important that fat for exercise
Fats: Ergogenic Aspects
Research dietary supplements that are marketed to help you burn fat and/or
enhance performance. Evaluate the supplement labels for content and
performance claims and compare them to what you have learned in this lesson.