Protein Timing: Protein Essentials (excerpt from the book)
By Jamie Hale
There’s a window of opportunity around workout time where protein consumption
enhances muscle protein synthesis above normal levels (in addition to the
protein synthesizing effects of resistance training). In this section, we will
examine what various researchers have found regarding protein timing. Some
authorities have reported that protein timing is just as important as total
protein intake. (My note: I doubt that.)
A session of heavy resistance training increases muscle protein synthetic rates
rapidly. MPS rates return close to baseline at approximately 36 hours. Some
studies have even suggested that protein synthesis rates stay elevated for up to
48 hours after a heavy resistance training session. If foods containing proteins
or
amino acids are delivered either immediately before exercise or in the
post-exercise period then the rise is greater. If insufficient supplies of amino
acids are provided, protein breakdown will exceed protein synthesis and there
will be no net accretion of protein.
A study conducted by Tipton showed the delivery of
amino acids to be
significantly greater during exercise when consumed pre-workout than
post-workout (Tipton 2001). The study was designed to determine whether
consumption of an oral essential amino acid, carbohydrate supplement (EAC)
before exercise results in a greater anabolic response than supplementation
after resistance exercise.
Six healthy human subjects participated in two trials in random order, PRE
(EAC consumed immediately before exercise) and POST (EAC consumed immediately
after exercise). A primed, continuous infusion of L-[ring-(2)H(5)]phenylalanine,
femoral arteriovenous catheterization, and muscle biopsies from the vastus
lateralis were used to determine phenylalanine concentrations, enrichments, and
net uptake across the leg. The results indicated that the response of net muscle
protein synthesis to consumption of an EAC solution immediately before
resistance exercise is greater than that when the solution is consumed after
exercise, primarily because of an increase in muscle protein synthesis as a
result of increased delivery of
amino acids to the leg.
In one study, the consumption of six grams of
amino acids plus 35 grams of
sucrose consumed one hour post-exercise and three hours post-exercise made
little difference because the same positive net protein balance resulted at both
times (Rasmussen et al. 2000). A comparison of the two studies indicated that
the response of net muscle protein balance was greatest when the
carbohydrate-amino acid mixture was consumed immediately before exercise.
A study by Borsheim indicated that essential amino acid ingestion after exercise
increased net muscle protein balance while non-essential amino acids were not
needed to increase balance. Borsheim also indicated that there is a dose
dependent response to essential amino acid ingestion (there may be a point of
essential amino acid availability above which no further stimulation occurs).
Additional support for this concept comes from the fact that net muscle protein
synthesis was similar when 20 grams and 40 grams of essential amino acids were
ingested after resistance exercise (Tipton et al. 1999). The response of net
muscle protein synthesis to the drink ingested two hours after exercise was
comparable to the drink consumed one hour after exercise.
In another study conducted by Tipton and colleagues, they evaluated the effects
of casein and
whey protein ingestion on protein balance after resistance
training. Twenty-three subjects consumed one of three drinks, one hour after a
bout of leg extensions. Subjects consumed the placebo, 20 grams of casein
protein, or 20 grams of whey protein. The results indicated that ingestion of
whey or casein protein after resistance exercise increases net muscle protein
synthesis.
In a review by Rennie and colleagues, they concluded that increasing amino
acid concentrations by intravenous infusion, meal feeding, or the ingestion of
free
amino acids increases muscle protein synthesis. They also concluded that in
the post-exercise period increased availability of amino acids enhances protein
synthesis.
In a recent study, Miller et al. compared the independent and combined effects
of a balanced mixture of
amino acids (EAAs + NEAAs) and carbohydrates on muscle
protein synthesis after resistance exercise. Adding 35 grams of carbohydrate to
six grams of mixed AA did not cause a greater stimulation of net muscle protein
synthesis than the AAs alone. From these results, it is clear that the
stimulation of protein synthesis by EAAs is not a caloric effect. The ingestion
of an additional three grams of EAA (difference in EAA content between mixed AA
and EAA groups) caused a much larger effect than adding 35 grams of carbohydrate
to the amino acid mixture, and 35 grams of carbohydrate alone had a minimal
effect.
Esmarck et al. reported that a protein-carbohydrate-fat supplement was effective
in stimulating muscle protein gain over a period of resistance training in
elderly men but only when ingested immediately after as opposed to two hours
after exercise. Levenhagen et al. found a greater stimulation of net muscle
protein synthesis when a protein-carbohydrate-fat supplement was given
immediately after aerobic exercise than when it was given two hours later.
Protein Timing: My Thoughts
Protein consumption (non limiting protein) immediately before or following the
workout has shown positive results regarding muscle protein balance. The
question is which one is better. The study that compared before and after showed
better results when consumed before. But does this make a significant difference
if we consider all of the other protein meals throughout the day?
My point is that this study compared two meals but didn’t look at other meals
throughout the day. These other meals have an additive effect on net protein
balance (the study was also done in a fasted state, and generally this would
only occur if the workout was done first thing in the morning).
I often recommend consuming a protein shake or meal before and after (within one
hour after workout) the training session. If you are consuming a mixed protein
meal, I suggest eating it 90 minutes to two hours before the session (consume
minimal amounts of saturated fat and fiber in this meal as it slows gastric
emptying). If consuming a shake before training, I recommend drinking a
whey
protein shake about 15–20 minutes before training. Ingesting any high quality
protein will probably be efficient post-workout.
If you will not be eating again for a long time after the post-workout meal,
a slow acting protein might be better (casein or mixed protein meal). The pre-
or post-workout meal plays an important role in protein gains, but it is the
overall effect of what you do throughout the entire day that will probably have
the biggest impact on net protein balance.
Copyright 2006 Jamie Hale
Jamie Hale is a sports conditioning coach, author, gym owner, and fitness
and nutrition consultant. He has contributed to numerous exercise and sports
publications (nationally and internationally) and has authored four books. He is
a member of the World Marital Arts Hall of Fame in recognition of his
conditioning work with martial artists and is considered by most in the industry
to be a specialist in agility and sledgehammer training. Jamie is also known for
his ability to get bodybuilders as lean and dry as bone for competition. To
learn more abut Jamie, visit his website at
www.maxcondition.com. He is available for seminars and camps.
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