Does fat build muscle

Does fat build muscle? by Alfredo Franco-Obregón, PhD


Types of fat:

Dietary fats, with the notable exception of cholesterol, generally consist of
long chains of carbon atoms known as fatty acids. Typically, the carbon atoms
within a fatty acid chain concatenate via single bonds, accounting for two
bonds per carbon atom. Carbon’s remaining two bonding electrons are dedicated
to forming molecular bonds with hydrogen atoms (see figure). In brief, the
carbon atoms within a fatty acid chain make four bonds. Typically, two of the
bonds are to other carbon atoms within the fatty acid backbone and two bonds
are made to hydrogen atoms that emanate from the chain. The word typically is
stressed here, because, as should be expected by now, there are exceptions.

A fatty
acid is said to be saturated when every carbon atom within the chain is bonding
with two hydrogen atoms, or is saturated with hydrogen atoms. Since the number
of hydrogen-carbon bonds (red bonds in figure) determines the energy content of
a hydrocarbon, saturated fatty acids have the highest energy content (ability
to produce the greatest amount of ATP) of any fuel source, particularly when
compared to an equivalent amount (in weight) of protein. Furthermore, the oily
nature of fats reflects the fact that they exclude water, something that
carbohydrates and proteins are unable to do. Consequently, fats are a highly
dense source of energy. These physical-chemical properties make fats
particularly well suited to being nature’s long-term energy storage molecule?
In fact, 98% of our entire energy reserves lie within fat deposits.
Unfortunately, energy density is not everything. The hydrogen-carbon bonds held
within fats are somewhat difficult for the cell to access, which is why
carbohydrates (sugars and starches) are still quicker sources of energy.

Long-chain saturated fatty acids tend to pack tightly together and, hence, have
restricted mobility. This, in turn, means that saturated fatty acids of more
than 16 carbons in length are solid at room temperature. Natural sources of
saturated fats are in fact mixtures of several different fatty acid species and
commonly arise from animal sources. Examples include cheese and butter.
Nevertheless, some plant oils also possess significant levels of saturated
fatty acids, including coconut and palm oils.

Unsaturated fatty acids contain carbon atoms connected by double bonds within
the chain. Obviously, a carbon that bonds twice with a neighbor has fewer bonds
available to make with hydrogen. That is, a double bond unsaturates a fatty
acid chain. More importantly, a double bond creates a kink in the fatty acid
chain. The downstream effect of this is that unsaturated fatty acids cannot
pack as closely together as saturated fatty acids. They are therefore liquid at
room temperature. Most vegetable oils are sources of unsaturated fatty acids.
The figure shows an example of an unsaturated fatty acid possessing a single
double bond – a monounsaturated fatty acid. Olive and canola (rapeseed) oils
are good examples of monounsaturated fats.

Polyunsaturated fatty acids contain multiple double bonds within the fatty acid
chain making them contort into rather complicated shapes. The omega-3 fatty
acids are examples of polyunsaturated fatty acids that are very important to
overall health. However, despite their extreme importance, polyunsaturated fats
will not be dealt with today, but will be the topic of a subsequent issue of
the Creatine Newsletter.

The fat-muscle connection:

Testosterone is one of our principal tissue-building hormones. Testosterone is
also responsible for the expression of secondary sexual characteristics in
males. Testosterone is thus anabolic and androgenic, respectively, which is why
females typically cultivate less muscle mass than males.

Expectedly, diet influences the production of our anabolic hormones. The
specifics, however, certainly remain sketchy to most. Early studies have hinted
at an interaction between dietary fat intake and serum testosterone levels. In
particular, it has been shown that athletes consuming diets containing 40% fat
expressed greater serum testosterone levels than athletes consuming a diet
consisting of only 20% fat. Nevertheless, the exact type of fat responsible for
this effect remained unknown for some time.

One of the most potent stimulators of testosterone release is exercise, which
is the reason why that exercise typically stimulates muscle growth.
Unfortunately, exercise also liberates cortisol, our principal catabolic, or
tissue consuming, hormone. An overproduction of cortisol will completely undo
the anabolic effects of testosterone. Therefore, the trick for someone trying
to build muscle mass is to provide an exercise stimulus that releases
sufficient amounts of testosterone to build muscle, while keeping cortisol
release to a minimum.

Study Title:Testosterone and cortisol in relationship to dietary nutrients and
resistance exercise.

The study examined the hormonal responses of twelve fit males to approximately
20 minutes of resistance exercise. Five minutes after performing 10 sets of
bench press and 10 sets of jump squats serum levels of testosterone and
cortisol were measured and correlated with dietary patterns. The subjects were
asked to report all they had eaten for 17 days prior to performing the exercise
session. The strongest positive correlation found was between dietary fat
intake and resting testosterone levels. Diets containing greater amounts of fat
were associated with higher levels of free testosterone at rest. Interestingly,
a strong negative correlation was found between protein intake and pre-exercise
testosterone levels. This finding is very important in light of the fact that
many athletes limit their intake of fats, while increasing protein intake in an
attempt to gain muscle mass. Obviously, this would have the exact opposite
effect on testosterone release as desired and will consequently interfere with
muscle growth.

The results from this study are summarized below.

Approximately 20 minutes of resistance exercise was sufficient to raise serum
testosterone levels significantly.

The exercise consisted of 5 sets of bench press (10 repetitions to failure) and
5 sets of jump squats (10 repetitions at 30% of each persons maximum squat)
with 2 minute rest intervals in between sets.

Jump squats released larger amounts of testosterone, due to the greater amounts
of muscle mass recruited in performing the tasks. In other words, large
multi-joint movements release more testosterone.

However, this exercise regimen was not enough to raise serum cortisol levels.

Reducing the rest intervals by half (one minute) may have been enough to induce
the release of cortisol.

Therefore, 20 minutes of resistance exercise is sufficient stimulus to release
testosterone, while avoiding the release of cortisol!!

Diets containing greater amounts of fats were correlated with higher resting
testosterone levels.

Specifically, the consumption of saturated fats was strongly correlated with
higher resting levels of testosterone.

Monounsaturated fats were the next highest predictor of resting serum
testosterone levels.

The absolute levels of polyunsaturated fats had no effect on serum testosterone

The increments in serum testosterone observed after exercise were not
influenced by diet.

Measuring serum testosterone levels at 5 minutes post-exercise may have been to
soon to reveal an effect of diet on post-exercise testosterone levels. Later
time points may be necessary to unveil a possible effect.

Surprisingly, higher protein diets were negatively correlated with plasma
testosterone levels.

The type of protein appears to matter. Previous studies have shown that animal
protein is more effective at raising stabilizing serum testosterone levels than
vegetable or egg proteins.

There was no apparent effect of nutrition of resting cortisol levels.


We live in a fat-phobic society. It now seems, however, that a little bit of
dietary fat is a good thing as far as testosterone is concerned. Given the
results of this study, I recommend that daily fat comprise 15-20% of your
diets, especially while undergoing heavy training. Protein should comprise
25-30% of your diet as to supply an adequate amount of substrates for the
production of new muscle tissue. Finally, carbohydrates should make up about
60% of your diet to maximally stock your energy reserves. It is also important
to keep you training sessions intense, but brief, as to avoid the release of
cortisol, but to stimulate the release of testosterone.

I will discuss in subsequent issues of the Creatine Newsletter exactly why fats
have this effect on serum testosterone levels, as well as how to specifically
combine carbohydrate and protein intake for an optimal anabolic status.


Despite the findings of this study, DO NOT adopt a more is better mentality
concerning the intake of saturated fats. It is important to keep in mind that
diets high in saturated fats also greatly increase your chances of developing
Coronary Heart Disease (CHD) in later life. On the other hand, monounsaturated
fats have been shown to have a positive influence on serum cholesterol levels
and, consequently, help protect against CHD. Therefore, canola oil (a
monounsaturated fat also known as rapeseed oil) may be a worthwhile addition to
your diet since it has a positive effect over free testosterone levels as well
as contains valuable polyunsaturated fats. Elevated testosterone levels may
also predispose one to certain types of cancers.

Scientific References

Jeff S. Volek, William J. Kraemer, Jill A. Bush, Thomas Incledon and Mark Boetes
(1997) Testosterone and cortisol in relationship to dietary nutrients and
resistance exercise. Journal of Applied Physiology Volume 82 (1), pages 49-54.

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