Researched
and Composed by
Jacob Wilson, BSc. (Hons), MSc. CSCS
The following faq / summary of protein research is based on an in-depth
publication on protein which can be accessed by clicking
here.
What is the optimal amount of protein that should be consumed each day?
With all the research that has gone on, it appears that this question
may be a bit too simplistic. I say this because X amount of protein
consumed in a day can create a totally different response when the
timing, pattern, and type of protein are considered. There are far too
many variables to develop one optimal set amount of protein.
What we can do is give some general guidelines. In essence much of the
research is based on nitrogen balance techniques. Protein is made of 16
% nitrogen. Therefore if the amount of nitrogen lost is equal to the
amount of nitrogen consumed from protein, then an individual’s needs are
said to be met. Because bodybuilders are concerned with growth, they
are more interested in the amount of protein that optimizes growth and
performance. When the amount of nitrogen retained is greater than the
amount lost then an individual is said to be in a positive state of
nitrogen balance, and assumed to be in a state favorable to muscle
growth.
A number of studies have analyzed the amount of protein needed and their
data can be summed up as follows.
1. The general consensus for protein needs for strength athletes ranges
from 1.2-2.2 grams of protein per kilogram of bodyweight daily.
2. A great deal of evidence has shown that protein intakes beyond those
required to obtain nitrogen equilibrium increases the rate at which
protein is oxidized (used as fuel). However, those same studies
indicate that these excess protein intakes increase the retention of
nitrogen and place an athlete in a more anabolic environment. As a
review, Tarnopolsky and colleagues (1992) found that when bodybuilders
were administered 0.8, 1.4, and 2.4 grams of protein per kg of
bodyweight that nitrogen balance was negative in the low protein
condition (-2.4 g of N per kilogram kg), and increased from moderate
(0.7 g N) to high (3.8) protein conditions. This same trend has been
seen in a number of studies.
3. Finally a number of studies have shown that very high protein intakes
produce greater gains in muscularity and strength than lower protein
intakes.
I suggest a minimum of 1.8-2.2 grams of protein per kilogram
based on the studies I have reviewed. This works out to a minimum of roughly 1 gram of protein
per pound of bodyweight daily.
Is there evidence that higher protein intakes ( > 1.8-2.2) can be
beneficial?
While this goes against the general consensus, it can be argued based on
increased nitrogen retention from higher protein intakes ( > 1.8-2.2),
that bodybuilders can benefit from such habits. Further most nitrogen
retention studies are based on adequate energy intakes. It is clear
that when an athlete is dieting that their protein needs increase
notably. For example, the bodybuilders in the Tarnopolsky et al. (1992)
study consumed nearly
5, 000 calories daily and still were calculated to need a minimum of 1.8
grams of protein per kg of bodyweight to reach nitrogen equilibrium.
Had they been consuming a lower intake of calories, their protein needs
would have most likely increased, as has been documented in a number of
studies.
Further, endurance exercise adds to the oxidation rates of proteins. As
an illustration
Consolazio (1978)
found that 2.8 g·kg-1·day-1
of protein
produced greater nitrogen balance and lean body mass gains then 1.4
g·kg-1·day-1
for 40 days in a
combined resistance training and endurance program.
It is critical to understand that studies have not been done in athletes
training with resistance exercise and or cardiovascular work up to
three-four hours daily. If 1.8 grams per kg was needed in the
Tarnopolsky et al. (1992) study for 75 minutes of training, it may be
increased with two daily sessions.
Finally, evidence also suggests that training twice daily enhances
overall protein synthesis in an additive fashion, thus allowing the
athlete to greatly increase their capacity to utilize protein.
My thoughts are perhaps best summarized by Wolfe (2000), who is arguably
the top researcher in the world on protein for athletics:
“our results, along with virtually all data in the
literature on the topic, suggest that increasing AMINO ACID
intake will increase muscle mass, with all other variables
remaining constant. Whereas this concept runs counter to
popular perception, real-life examples abound in obese
individuals who have significantly elevated muscle mass
despite living sedentary lives. Thus, it is likely that increasing AMINO
ACID intake in accord with the principles discussed above to
optimize effectiveness will promote muscle anabolism, whether
in depleted individuals such as the elderly or in active
athletes trying to increase muscle mass. The exact
nutritional approach will determine the extent of anabolic
response(emphasis added).”
Should I eat slow or
fast digesting proteins?
Digestion rate has been demonstrated in a number of studies to effect
both muscular protein synthesis and breakdown. Essentially, the overall
effect which determines whether you gain muscle tissue or lose muscle
tissue is centered around whether or not protein synthesis exceeds
protein breakdown.
There are a number of problems with studies that have been conducted.
First, many of the studies have compared whey protein to casein as
representatives of fast and slow digesting proteins respectively. Whey
protein has a higher quality of protein than casein as determined by its
essential amino acid profile. In particular it is higher in leucine
content. Leucine is thought to serve as a signaler molecule for the
quality and quantity of protein intake, and is a potent stimulator of
protein synthesis. To control for this, studies generally give more
casein protein than whey. For example Boirie and colleagues (1997) gave
individuals 43 grams of casein and only 30 grams of whey. While they
both had the same leucine content, the amount of protein served was
greater in the casein condition, which certainly can confound the
results.
Fortunately recent studies have investigated what happens when both whey
and casein contain the same amount of protein. The other problem is
that a number of studies have measured whole body protein synthesis.
But this does not differentiate between muscular protein synthesis, and
say protein synthesis in organs such as the liver. Again however, there
have been studies which correct for this. Overall, the evidence is
strong enough to tease several trends out of the background noise of
confounding variables. Here is the general consensus of what studies
suggest:
Slow vs. Fast digesting proteins when taken alone
1. Fast digesting proteins raise protein synthesis to a greater extent
than slow digesting proteins. For example, 30 grams of whey raised
whole body protein synthesis by 68 % compared to only 34 % in 43 grams
of casein. The rationale is that Essential amino acids serve as both
building blocks for muscle tissue, as well as signaling molecules which
trigger protein synthesis. Studies suggest that up to a point, the
higher the blood levels of amino acids are, the higher protein synthesis
will be stimulated. Because whey digests rapidly, plasma amino acid
levels rise rapidly and to a greater extent than casein, which rises
slowly.
2. Slow digesting proteins lower protein breakdown, while a fast
digesting protein does not have these properties. The rationale is that
an increase in amino acid levels must occur for a long enough time, or
it cannot exert its anticatabolic effects. Whey protein increases amino
acid concentrations rapidly, but also falls rapidly. In contrast casein
raises amino acid levels slowly and remains elevated for a while.
3. When both proteins taken alone are compared over a seven hour
period, casein produces greater whole body protein balance than whey.
The problem is, unless you are going to sleep, you are not waiting seven
hours before your next meal! And if you are extremely serious about
growth, you may not even wait that long during a nights sleep.
Slow vs. Fast digesting proteins when taken with carbohydrates and fats
1. In short, when taken with carbohydrates these results reverse.
Generally the addition of other macronutrients decreases protein
breakdown when taken with whey, but not to a great extent with casein.
While additional nutrients slow digestion, whey still rises more
rapidly. Further, the addition of carbohydrates does not greatly affect
protein synthesis. Therefore, when combined with a carbohydrate, a fast
digesting source of protein such as whey appears to be more anabolic.
This has also been supported in a study which compared an essential
amino acid / carbohydrate supplement and a meal with casein and other
nutrients and their direct effect on muscular protein synthesis. Both
had the same amount of essential amino acids (15 grams), yet the
supplement produced a markedly higher anabolic response. The rationale
was that the fast digesting amino acid source increased blood amino acid
levels so rapidly, that it decreased the efficiency with which other
organs like the liver could take up the amino acids, leaving more
available for muscular protein synthesis.
In summary, it appears that when a single meal is administered with
carbohydrates that a fast digesting source may be desirable. However,
when administered without carbohydrates a slow digesting source may be
more desirable. This would suggest that before bed would be an
excellent time to take a casein containing meal, such as cottage
cheese. Namely because the meal before bedtime is typically lower in
carbohydrates, to avoid fat deposition.
What is the optimal pattern of protein digestion?
Because bodybuilders eat numerous times within a single day, a seven
hour period of food abstinence, when comparing digestion rate is highly
improbable outside of sleep, and therefore not relevant to our waking
hours. This is why it is important to address the pattern of digestion
of protein intake.
The pattern of digestion simply means how an individual consumes their
protein throughout a day, and what sources are utilized during this time
zone.
There are a few key points to understand when considering the pattern of
digestion.
1. An increase in extracellular amino acid levels triggers protein
synthesis, while a decrease lowers protein synthesis, despite absolute
concentrations. What I mean is this is if your amino acid levels rise
250 %, and then fall to 150 % above resting levels, protein synthesis
will most likely lower to basal levels again. However, if you raise
amino acid levels at that point, you will get another increase in
protein synthesis.
2. The machinery which increases protein synthesis goes refractory when
amino acids are raised and held at a constant rate for an extended
period of time. For example, in studies in which authors increase blood
amino acid levels through intravenous infusion, and maintain those
levels at say 200 % above resting, after 2 hours protein synthesis will
return to resting levels. The system may act on some form of negative
feedback.
3. In response to this, a number of scientists have suggested that
continually consuming slow digesting proteins can mimic intravenous
infusion, and though amino acid levels are risen for hours on end, cause
the system to lower protein synthesis. However, a fast digesting
protein source, like whey, or essential amino acids will rapidly rise,
and possibly fall within 1-2 hours.
4. Studies show that with fast digesting proteins or essential amino
acids, that a similar anabolic response will occur when they are
delivered 1 hour apart. So let’s say that you consumed 15 grams of EAAs
at 12:00 right after working out, and then again at 1:00. If at 12:00
protein synthesis increased by 50 %, you would most likely get the same
response an hour latter. The rapid rise in amino acids and drop, may
keep the system from lowering protein synthesis in response to
continually maintaining a similar amino acid concentration.
5. Rises in protein synthesis throughout the day are additive in
nature. This means that if you normally synthesize X amount of
proteins, and working out increases protein synthesis by Y amount, then
total protein synthesis for the day would be X + Y. If you then
consumed 2 extra essential amino acid drinks throughout the day, each of
which increased protein synthesis by Z amount (2Z), then protein
synthesis would be X + Y + 2Z. Cool ha!? This means that you can take
advantage of rapid increases in amino acids.
Overall suggestions. My overall suggestions are summed by a recent
study. In the study they gave participants their normal 3 meals a day,
and then added 3 servings of essential amino acids combined with
carbohydrates between meals. Here is what it looked like
Figure 6 - Meal schedule with added CAA supplement. From Paddon-Jones
et.al.(2004)
They found that protein balance increased tremendously compared to the
anabolic response of the participant’s normal meals. Therefore my
overall suggestion is to consume a minimum of 3-5 of your normal meals
with normal whole food proteins. Then, the rest of your meals may
optimally come from fast digesting proteins for a minimum of three
protein shakes. Finally before bed time consume a casein containing
protein source such as cottage cheese. This adds up to a minimum of 7
meals, and does not include the pre workout amino acid shakes.
I will outline the meal plan shortly. But the point is simple. If you
continually consume slow digesting proteins, you may stunt protein
synthesis. The above is a sample of a minimal game plan. Below is a
hardcore sample with a bodybuilder who trains up to two times daily
Extremely
Hardcore Sample Plan
Overall game plan: To spike protein synthesis in an additive fashion
throughout the day. To do so you will need several servings of fast
digesting sources of protein.
Meal 1 – 6:00 in the morning
Carbohydrate – to suppress protein degradation
Fast digesting source of protein – to spike protein synthesis
Supplement - 7:00 –
Essential amino acids, and glutamine - Increase extracellular amino
acid concentrations,
7: 30 – Begin workout – The workout will increase blood flow to working
muscles, combined with the increased extra cellular amino acid levels,
an incredible delivery of these vital substrates will be delivered to
your muscle tissue.
Meal 2 - 8:30-9:00 – End of workout –
Fast digesting carbs – depress protein degradation
Glutamine, and whey protein – Blood flow is still severely increased to
muscle tissue, and will have an additive and possibly synergistic effect
when combined with a rich supply of amino acids.
Supplement - 10:00 – 10:30
Consume a small fast digesting protein shake or Essential amino acids to
further spike protein synthesis in an additive fashion to the last
meal. Protein synthesis can be seriously increased with a serving as
small as 6-15 grams of Essential Amino acids, or 20-40 grams of whey.
Meal 3 – 11:30 - Normal Meal –
Mixed protein sources from various meats. – You are probably tired of
eating for what seems like every other minute! So give yourself a
break, have a normal meal, and don’t worry about eating for 2 to 3 hours
(no more than three!)
Meal 4 – 2:00 to 2:30 - Faster digesting sources of protein like
egg whites and super lean meats (an omelet is great) so that the fat
does not hinder digestion.
Meal 5 – 4:30 – Mixed protein sources from various meats
Supplement – 6:00 – Essential amino acids and glutamine
6:30 – Train
Meal 6 - 8:00 – Post workout shake, in smaller quantity then
earlier workout
9: 00 - Supplement – small serving of whey or EAAs
Meal 7 - 10:30 – Cottage cheese, broccoli, glutamine – Lower
overnight protein degradation
Wake up in the middle of the night – Turn over throw down a casein
containing supplement like pro score, milk, or casein and go back to
sleep!
Sleep and start over again.
The above diet is only concerned with protein sources. I only discussed
the carbohydrate source with breakfast, post workout, and before bed
time as it is not the primary concern of this article.
What about the timing of protein intake?
Timing of post
workout nutrition.
Nutrient
timing is a huge topic in exercise nutrition (For a thorough analysis of
post workout nutrition timing, readers are referred to Knowlden (2003,
A Scientific Investigation into the Rationality of Post Workout
Carbohydrate Consumption ).
And rightfully so. In essence the way you time the consumption of a
given nutrient has tremendous effects on the anabolic effect of that
nutrient. As an example, Dr. Esmark and colleagues (2001) compared
consuming a protein supplement immediately after exercise or after a two
hour delay. It was found that the group that consumed the drink
immediately after exercise increased muscle mass, where as the delay
group had no significant increases in muscle tissue. Similarly
Levenhagen et al. (2001) found that delaying a protein supplement for 3
hours resulted in a net decrease in protein balance, where as the
immediate condition increased protein balance. And protein synthesis
was 3 times greater in the early condition than the late
condition!
There are a number of reasons for these findings such as blood flow
differences. Blood flow is greatly enhanced after exercise to the
working musculature, and blood is shunted away from other organs. This
results in a greater delivery of amino acids to muscle tissue, and a
lower percentage of amino acids being taken up by splanchnic tissues
such as the gut. The timing of the post workout drink should be
immediately after training, so as to take advantage of this primed
anabolic environment.
How should I time my pre workout nutrition?
During exercise the muscles which are ferociously working need a greater
supply of energy and oxygen. In fact, the percentage of blood delivery
to working muscles can increase by 80 %! Pre workout nutrient timing
takes advantage of this occurrence. You see, by administering EAAs
30-45 minutes before a training session, the trainee will (A) have a
heightened supply of the nutrients critical for muscle repair and (B)
deliver those nutrients to the muscle at a rate much greater than could
occur at rest.
This was recently studied at the University of Texas medical branch, by
a group of scientists who found that consuming a supplement containing
EAAs prior to exercise increased blood flow up to 324 % during exercise,
in comparison to only 200 percent for those individuals who did not
consume the drink. If that wasn’t enough, the exercisers increased
amino acid deliver to the leg by 650 %, leading to a much greater repair
of the working muscle tissue.
Again, the rationale is based on combining the effects of increased
blood flow to the musculature and enhanced amino acid availability.
Which is better and what should I have, a pre workout or post
workout meal?
This is actually a common question. However, to me, asking this
question is similar to asking “ What is better, lunch or dinner?” In
reality, you should eat both meals. Similarly, both pre and post
workout meals are vital to an athletes success. Blood delivery is
increased when training, so you will want to have a source of amino
acids prior to training. In fact, studies show that normally a
bodybuilder is in negative protein balance while training, this is
because protein synthesis has little change during the exercise session,
but protein degradation increases, leading to a net loss of muscle
tissue. Supplementation prior to exercise changes this situation.
However, after working out muscle blood flow is still increased, and
consuming another meal is critical to taking advantage of this anabolic
window (I would again refer you to Knowldens (2003, 2004) work on the (
The Window of Opportunity &
the Rationality of Post Workout Carbohydrate Consumption
). Further, as was discussed previously studies clearly show that
consuming an amino acid supplement one hour apart results in similar
anabolic responses.
In summary, approximately 30 minutes before training an athlete should
consume an essential amino acid based supplement, or at least a fast
digesting source of protein such as whey. After resistance exercise
bodybuilders should consume a rapid digesting source of carbohydrates
and proteins as described by Knowlden (2003, 2004, also see Wilson, G.
2003,
Dextrose, Maltodextrin, and Sodium an In Depth Analysis).
What is the
difference between low carbohydrate or high fat diets on the sparing of
muscle tissue?
This is an interesting topic. Earlier studies indicated that
carbohydrates spared muscle proteins to a higher extent than fats.
However, current evidence suggests that they both have similar muscle
tissue sparing effects. What I mean is this: carbohydrates and fats
are both sources of energy. When dietary energy provision is low, the
body will breakdown proteins at a heightened extent for energy.
Therefore a high provision of dietary energy lowers this effect.
Diets which are lower in carbohydrate and higher in fats spare muscle
proteins similarly to carbohydrates. Further, both of these
macronutrients have indirect anabolic effects on muscle tissue through
the stimulation of hormones. Carbohydrates primarily stimulate insulin,
which is known to hinder protein degradation and increase protein
synthesis if amino acid concentrations are maintained, and specifically
when insulin levels are very high such as after exercise. Fats,
particularly saturated fats, stimulate anabolic hormones such as
testosterone.
In this context, it is important for athletes to provide some nitrogen
sparing energy source with meals. When meals are low in carbohydrates
they should be higher in fats, and vice versa.
If this is true, then why do I feel like it’s harder to maintain
muscle tissue when low carbohydrate dieting?
Recently my colleague Gabriel Wilson and I did an extensive review on
factors involved in maintaining performance. The evidence kept pointing
to the same variable
à Intensity. If you lower intensity adaptations in
strength and muscle size appear to decrease proportionally. Because
carbohydrates are the main source of energy for hypertrophy inducing
sets ( 8-12 repetitions), bodybuilders on low carbohydrate diets have a
hard time maintaining the intensity of the stimulus, and therefore
deadaptation occurs.
Further, insulin is a potent hormone for enhancing protein balance,
which is necessary for muscle growth. All in all, if you want to
stimulate an adaptive response, you must expose the system to greater
and greater stimuli. In this context, carbohydrates appear to play a
critical role.
What is the interaction between carbohydrates and protein in terms of
insulin release?
They appear to work synergistically. Meaning carbohydrates and protein
combined stimulate insulin secretion to a greater degree than when
consumed alone.
How is protein
quality determined?
There are
several ways to determine the quality of a protein. But, let’s just sum
it up and say that most are based on the essential amino acid profile of
the protein in question. As you know, there are 20 amino acids, 11 of
which can be produced by the body (non essential), and nine of which
cannot (essential)! Just one missing essential amino acid, and an
individual can enter into serious negative nitrogen balance, if they
were to only consume protein from that source.
Does protein quality have an effect on muscle growth?
Absolutely! This has been demonstrated in a number of
studies. For example Phillips et al. (2005) administration either milk
protein or soy protein after participants trained with weights. After
12 weeks of resistance training, it was found that the group that
consumed milk protein had greater muscle mass than the placebo group who
only had maltodextrin. However, there was no difference between the soy
and maltodextrin group!
Generally animal based products are the highest quality proteins. These
products consist of meats such as beef, and chicken, as well as egg
products, and milk based products. One study conducted by Campbell and
colleagues (1999) found that subjects who consumed a meat based protein
diet, compared to a vegetarian based protein diet, gained lean body
mass, and lost body fat in a 12 week resistance trained program.
However, the vegetarian group lost muscle tissue and gained fat! For
vegetarians who cannot consume meat, an alternative would be whey
protein, and casein based products.
There are a number of reasons why higher quality proteins stimulate a
greater degree of growth. Two of the most important are as follows:
1. Essential amino acids act to stimulate protein synthesis directly.
Meaning as their extra cellular concentration increases protein
synthesis increases. Non essential amino acids do not have this effect.
2. Proteins that are deficient in one or more of the essential amino
acids, appear to increase protein synthesis in the splanchnic tissues
such as the liver, and depress protein synthesis in muscle tissue. The
opposite occurs for proteins with a high profile of essential amino
acids. One of the reasons is that a number of the essential amino
acids, particularly the branched chain amino acids are poorly absorbed
by the liver and other splanchnic tissues. So they have a much greater
availability for muscle tissue!
Should I combine proteins to increase their quality?
In short, yes! Complementary proteins is a notion popularized by
vegetarians. For example grains are deficient in lysine, but high in
methionine, while legumes are high in lysine, and low in methionine. By
combining the two you complete the amino acid profile. Studies show
that complementary proteins should be eaten at the same meal, or you
will have additive effects of ingesting multiple incomplete protein
meals, as opposed to additive effects of complete protein meals.
The concept of complimentary proteins can also be used for meat eaters.
Typically proteins such as steak, and chicken, are higher in some amino
acids than others. By combining the two proteins in a single meal, you
increase the quality of that meal.
In summary, I suggest consuming the majority of your proteins from meat
based products. Further it is optimal to combine protein sources. For
example, an egg white omelet with lean chicken is excellent. Another
example is lean turkey and steak in the same meal.
Complementary proteins should be consumed in the same meal.
What is the point of protein supplements when you can just consume
protein from whole foods?
There are numerous reasons. First, protein supplements such as whey are
extremely cheap relative to whole meats. But, what is interesting is
that they may be somewhat more anabolic. Fast digesting proteins like
whey, and Essential amino acid supplements, like Champion Nutrition’s
Essential Amino acid shooter have been shown to be more anabolic then a
larger meal containing the same amino acid profile! But why would two
meals containing the same essential amino acid profile differ in their
anabolic response? Padon-Jones et al. (2005) suggests that the faster
digestion of the protein supplement may decrease the efficiency of
uptake of amino acids in splanchnic tissues, and leave more available
for muscle tissue.
Further, consumption of an essential amino acid supplement, with high
doses of leucine has been shown to be more anabolic than a normal
protein supplement. Leucine is known to both increase protein synthesis
as well as increase the sensitivity of muscle tissue to insulin’s
anabolic effects!
How much protein can
you consume in a single serving?
Really I
think the question is what is optimal? Well, it appears that increasing
extra cellular EAA levels will directly stimulate protein synthesis
proportionally to the increase in a curvilinear fashion. This means
that increasing EAAs early on raises protein synthesis in an almost
direct relationship as amino acid levels rise up to 80%. After this,
protein synthesis continues to rise, but in a slower fashion. However,
the point at which an increase in amino acids stops stimulating protein
synthesis is unknown.
What we do know is that there appeared to be no difference between 20
and 40 grams of essential amino acids, which in a normal protein would
amount to being no difference between 40-50 grams of protein to about 80
grams of protein in one serving. However in a study by Dangin and
colleagues (2003), they found that increasing protein intake with whey
from 22 to 33 grams markedly increased protein synthesis. However, it
should be noted that this will vary with bodyweight. For example, the
protein intake I mentioned was an average of 33 grams in the high
condition. But in reality the authors prescribed to each participant
0.48 grams of whey protein per kg of bodyweight. Therefore a roughly
200 pound man, would have consumed 43 grams of protein.
Therefore the optimal level of protein may hover between 0.48 grams
of protein per kg of bodyweight per meal (it could be less or it could
be more). Further, this optimization appears to be based on the
essential amino acid profile. When consuming essential amino acids,
studies suggest that >= to 20 grams should be sufficient.
It should be emphasized that the above recommendations are limited and
that more studies will need to be conducted to see what is truly
optimal.
Conclusions
I must say that this series has been an experience. Protein consumption
is an extremely complex subject. Fortunately a number of great
scientists have conducted exquisite research relative to a great number
of variables effecting the anabolic properties possessed by a given
bolus of protein.
I could go on and on. But suffice it to say. If you apply the
principles laid out in this series you will become leaner, fuller, and
heck freakier as well!
Yours in Sport
Jacob Wilson
jwilson@abcbodybuilding.com
President Abcbodybuilding.com / The Journal of HYPERplasia Research
© ABC
Bodybuilding Company. All rights reserved. Disclaimer
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