Saturday, July 4, 2009

Macronutrient Basics: Fats

11:49 PM by dody ·
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Fats are deceivingly simple molecules. Fats are just atoms of carbon linked together in a chain. Assuming nothing is attached to either end of the chain (a free fatty acid), you will nd a carbon surrounded by hydrogen (CH ) on one end, and on the other end you will nd a few oxygens (COOH 3 or COO-). Surrounding all the carbons are hydrogen atoms. Now what gives vari- ous fats most of their biological character is the length of the chain and the number of double bonds. The more carbons, the longer the chain. A double bond is what you get when you take away a few hydrogens and the bond “doubles up” on the carbon (see picture). These double bonds are very important and dictate (along with the length and shape) the type of fat and its e ect on the body.

For example, a fatty acid chain with no double bonds is said to be “ satu-
rated” and is known as a saturated fat. These are fats that are hard at room
temperature. Although much maligned, saturated fats do have a place in
the diet of athletes, as will be explained later in this chapter. Put a single
double bond in the fat and it is a“ monounsaturated” fat. It becomes a“ poly-
unsaturated” fat, as you make more double bonds.

Olive oil is an source of monounsaturated fat, and oils such ax, corn, soy-
bean, etc. are sources of polyunsaturated fats, as they have multiple dou-
ble bonds. The more unsaturated a fat is, the lower melting point it has - so
these fats are liquid at room temperature.

Highly unsaturated fats such as those in sh oil actually remain liquid at
very low temperatures. This is why cold water sh have high levels of these
lipids (fats).

Saturated fatty acid: (caproic acid)

CH3-CH2-CH2-CH2-CH2-COOH
CH3-CH2-CH2-CH2-CH2-CH=CH-CH2-CH=CH-
CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH
Like the essential amino acids, the body has two essential fatty acids it can-
not make itself – due to a lack of the necessary enzymes – so they must be
supplied by the diet and are aptly called the “ essential fatty acids” or EFAs.

The two EFAs are linoleic acid (LA) and alpha-linolenic acid ( ALA). LA is
known as an “ omega-6” fatty acid and ALA is known as an “ omega-3” fatty
acid. Minimum requirements for the essential fatty acids are 3 - 6% of daily
calories for LA and 0.5 - 1% of daily calories for ALA. Sources such as ax,
hemp, and perilla oils contain signi cant amounts of ALA, while sa ower,
sun ower, and grapeseed oils are high in LA.

As with many vitamins and minerals, it is di cult to get optimal amounts of
unprocessed essential fatty acids (especially the omega-3 fatty acids) from
our heavily processed food supply. The term “ omega-3 fatty acid” should
ring a bell for the reader.

Fish oils are a well-publicized source of the omega-3 fatty acid metabolites,
EPA and DHA, which our bodies make from ALA and has been shown to
have many bene ts. Although early research told us we need a bit more LA
than ALA, in practice, I nd that a diet higher in ALA produces the best re-
sults for athletes looking to build muscle with minimum increases in body
fat.

Americans tend to get their fats from saturated fats, rancid fats, and highly
processed fats (which contain by-products such as trans fatty acids), thus,
giving fats a bad name. EFAs are not to be avoided as a “bad fat” because all
fats are not created equal.

From a general health standpoint, EFAs are involved in literally thousands
of bodily processes essential to our health and general well being. Immu-
nity, aging, hormone production and hormone signaling... well, you get
the point. As one would expect, EFAs have been found to have many health
uses including cholesterol reduction, possible cancer prevention and the
treatment of in ammatory conditions.
In particular, the omega-3 fatty acids are anti-lipogenic (block fat storage),
anti- catabolic, and anti-in ammatory. They also increase beta-oxidation
(fat burning!), improve insulin sensitivity, increase thermogenesis and do
a whole lot more that we don’t have the space, time, or need, to cover in
this chapter.

Recent research has found that EFAs, in particular the omega-3 lipids, con-
trol gene transcription. Omega-3 lipids appear to have the unique ability
to enhance thermogenesis and thereby reduce the e ciency of body fat
deposition.

For the more technically adept: omega-3 lipids play essential roles in the
maintenance of energy balance and function as fuel partitioners. They do
this by directing glucose toward glycogen storage and directing fatty acids
away from triglyceride synthesis and assimilation - thus aiding fatty acid
oxidation (fat burning).

EFAs exert their e ects on lipid metabolism and thermogenesis by up-
regulating the transcription of uncoupling proteins and increasing the en-
coding for genes that produce enzymes involved in fatty acid utilization;
while down-regulating the transcription of genes encoding for enzymes
involved in lipid synthesis, such as fatty acid synthase (FAS).

A lack of EFAs, especially the omega-3 EFAs, appears to be one of the dietary
factors leading to the development of obesity and insulin resistance seen
in Syndrome X. Syndrome X is a process whereby the body becomes resis-
tant to insulin. The result is a long list of health problems, such as weight
gain, heart disease, high blood pressure and full blown diabetes.

Of particular interest, the body makes compounds called prostaglandins
– as well as other highly unsaturated compounds – from both of the essen-
tial fatty acids. Prostaglandins are highly active, short-lived, hormone-like
substances that regulate cellular activities on a moment to moment basis.

Prostaglandins are directly involved with regulating blood pressure, in-
ammatory responses, insulin sensitivity, immune responses, anabolic/

unknown. To sum up without going into a long and boring biochemical
explanation: omega-3 fatty acids are responsible for forming anti-in am-
matory prostaglandins and omega-6 fatty acids are responsible for many
of the pro-in ammatory prostaglandins (in addition to the many other
products derived from EFAs).
->Read More

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