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Q: Nutrient timing, weightlifting and rebuilding muscle:eating before/after workout ( Answered 5 out of 5 stars,   0 Comments )
Subject: Nutrient timing, weightlifting and rebuilding muscle:eating before/after workout
Category: Health > Fitness and Nutrition
Asked by: donphiltrodt-ga
List Price: $36.00
Posted: 09 Apr 2005 12:16 PDT
Expires: 09 May 2005 12:16 PDT
Question ID: 507216
Here's the question I want answered:...

I've heard that after weight training, there is a 1-hour window during
which the body gathers all the nutrients it needs to rebuild and grow
the exercised muscles.  Is this true?

Here's the larger context of the question (but it's not what I'm
necessarily asking you to research):...

Can I restrict my calories thru the day, but eat more (carbs and
protein) before and after my workout and successfully build my

So... for the Official Question, please find credible research that
addresses this question and/or find some credible authoritative voices
on the subject.

You'll likely find a variety of differing opinions.  Your answer
should include links to the various "schools of thought" so that I
can, in a future GA question, request further research or synthesis of
the opinions you find.
Subject: Re: Nutrient timing, weightlifting and rebuilding muscle:eating before/after workout
Answered By: welte-ga on 10 Apr 2005 18:44 PDT
Rated:5 out of 5 stars
Hi donphiltrodt-ga,

Thanks for your question on the timing of nutrition to maximize muscle
building.  Please note that this not an endorsement for any
nutritional regimen and does not constitute medical advice.  An
individual should consult with a physician before undertaking any new
exercise routine or nutritional modification.

As you state, there has been some controversy around this topic.  For
this reason, I have focused on scientific articles, primarily review
articles, that review all of the available scientific evidence on a

A recent journal article, from Medicine & Science in Sports & Exercise
(the official journal of the American College of Sports Medicine)
addresses your question directly.  Here is the reference for the
Volek JS. Influence of nutrition on responses to resistance training.
[Journal Article] Medicine & Science in Sports & Exercise.
36(4):689-96, 2004 Apr.
Unfortunately, the full text of this article is not freely available. 
I can, however, provide some excerpts that may help answer your

The abstract of this article is available online, and will help you
decide if the full text is worth obtaining.  You can find it here:

I have also reproduced the abstract here, for convenience:
"A variety of dietary practices designed to enhance acute responses
and chronic adaptations to resistance training have been examined with
little consensus on the optimal nutritional approach for maximizing
muscle and strength gains. From a scientific and practical
perspective, the quantity, quality, and timing of nutrient ingestion
around a workout are important factors to consider. Manipulation of
exercise and nutritional variables can alter events that impact
adaptations to training by a variety of mechanisms related to nutrient
availability and uptake into tissues, hormonal secretion and
interactions with receptors on target tissues, and gene transcription
and translation of proteins that eventually impact protein,
carbohydrate, and lipid metabolism. If the nutrition-mediated
postresistance exercise change in any of these processes is of
sufficient magnitude and duration, then over time an effect of muscle
size, strength, and body composition is possible. To date, the
majority of research has concentrated on providing carbohydrate alone
or combined with protein before or after resistance exercise.
Carbohydrate and protein intake significantly alters circulating
metabolites and the hormonal milieu (i.e., insulin, testosterone,
growth hormone, and cortisol), as well as the response of muscle
protein and glycogen balance. The pathway of adaptation is proposed as
a model to assist in integrating research findings from the current
body of literature and future studies examining various diet and
resistance exercise configurations."

You can likely obtain a reprint copy of this article from the author,
Jeff Volek.  Here is his e-mail:  Authors are
usually very willing to e-mail PDF's of their research articles.


As the abstract states, the article examines the quantity, quality,
and timing of nutrient ingestion in relation to a workout.  The paper
looks at both acute (short term) and chronic (long term) adaptations
to resistance training that the body goes through.  The paper goes on
to discuss the intricate hormonal mechanisms believed to play a role
in how these three factors influence delivery and absorption of
nutrients by muscle and other tissues.  Lending more strength to this
paper, the author has looked at multiple other studies to attempt to
synthesize the current findings on each topic.  The bibliography of
this paper is a useful resource for further research on the topic.


From the section of the paper discussing the short-term effects of
protein and carbohydrate intake on protein metabolism:

" Infusion of amino acids or exogenous administration of amino acids
with or without carbohydrate stimulates protein synthesis after
exercise (2,4,45,59). Compared with placebo, carbohydrate intake (1 g
glucose·kg-1 body mass) immediately and 1 h after a bout of resistance
exercise resulted in higher plasma glucose and insulin, decreased
myofibrillar protein breakdown and urea nitrogen excretion, and
slightly increased fractional muscle protein synthetic rate (50).
These favorable effects of carbohydrate intake on protein balance were
achieved from a simple redistribution of the timing of the subject?s
habitual dietary energy intake. Consumption of both protein and
carbohydrate results in even greater effects on protein balance.
Protein synthesis was stimulated ~400% above preexercise values when a
protein and carbohydrate supplement (6 g essential amino acids and 35
g sucrose) was consumed 1 or 3 h after a bout of resistance exercise
(45). Consumption of this same protein and carbohydrate supplement
immediately before exercise resulted in increased amino acid delivery
to muscle and greater net muscle protein synthesis compared with
consumption of the supplement at various times after exercise (58).
These effects were evident in both men and women. In summary, there
appears to be an interaction between increased availability of amino
acids and increased insulin after exercise and the timing of
supplement ingestion (i.e., immediately before exercise) may be
important to maximize the anabolic response (58). Consumption of a
protein-carbohydrate supplement at times around exercise (i.e.,
immediately before and immediately after exercise) may provide the
ideal anabolic situation for muscle growth.

The amino acid composition is an important consideration when
examining the effects of protein feeding. Essential amino acids have
been shown to be primary regulators of muscle protein synthesis with
little contribution from nonessential amino acids (54,59,60). The
branched-chain amino acids, particularly leucine, appear to be the
most important stimulators of skeletal muscle protein synthesis (31).
Recent work indicates that it is the extracellular levels of essential
amino acids in the blood that regulate muscle protein synthesis as
opposed to intramuscular amino acids (8). Certain amino acids may also
regulate protein breakdown (30); however, these affects appear to be
less important in magnitude than those controlling protein synthesis
at physiological concentrations of amino acids."

The numbers above refer to references in the full version of the paper
from which these statements have been derived.  Essentially, the above
comparison of multiple studies finds that while intake of carbohydrate
and protein 1hr or 3hr after exercise increases protein synthesis,
intake of the same carbo/protein mix just prior to exercise was more
effective in the short-term.

The important question, however, may be how does nutritional
modifications effect the long-term chronic metabolism of protein.  The
above article discusses this point as well:

"The finding that protein and carbohydrate intake can alter the acute
phase response to resistance exercise in favor of anabolism is
intriguing; however, a more pertinent question is whether these
repeated metabolic alterations are of sufficient magnitude to alter
long term adaptations to resistance training. Although a strong
theoretical basis exists for expecting a beneficial effect of protein
and carbohydrate supplementation during resistance training, no
studies have systematically addressed the timing of supplementation
and linked acute physiological responses to chronic adaptations in the
same study."

The article goes on to discuss the studies that looked at timing of
carbo/protein supplementation with respect to muscle size and
strength.  Here is the relevent excerpt:

"Supplying additional protein or amino acids may augment adaptations
to training but precise timing of protein intake may enhance the
response further. A recent study in elderly men investigated the
effect of timing of protein-carbohydrate supplementation on muscle
size and strength responses to 12 wk of resistance training (14). The
supplement (10 g protein, 7 g carbohydrate) was consumed immediately
or 2 h after each training session. The group who ingested the
supplement immediately after exercise had significantly greater
increases in (mean ± SEM) lean body mass (1.8 ± 0.7% vs -1.5 ± 0.7%),
muscle fiber area (22 ± 6% vs -5 ± 6%), and quadriceps femoris area (7
± 1% vs no change). These data indicate that altering the timing of
calories, without altering the amount consumed, can impact chronic
adaptation to training. Specifically, early intake of protein and
carbohydrate after a workout is more effective at increasing skeletal
muscle hypertrophy and lean body mass than a supplement consumed
later. These findings are in conflict with a study that showed no
differences in acute measures of protein balance when protein was
ingested 1 or 3 h after exercise in healthy young subjects (45). This
apparent discrepancy related to timing of protein ingestion highlights
the importance of linking acute studies that measure protein kinetics
to long-term training studies that assess outcome measures related to
muscle size."

As stated, one must not look simply at short-term acute change in
protein metabolism, but rather at the long-term effects.  This is
likely the source of conflicts in this field of study, where effects
on protein metabolism in short-term studies have been extrapolated to
long-term effects that may or may not be true.  When the long-term
effects were finally studied, they at times conflicted with these
earlier extrapolations, but are based on data and are therefore more
believable in the right  context.


So, the important result is that ingestion of the supplement described
in the paper (10g protein, 7g carbohydrate) immediately after exercise
results in a significantly greater increase in lean body mass, muscle
fiber area, and quadriceps femoris area.

Of course, the overall picture is complicated by hormonal influences
(testosterone, insulin, etc.), which are also discussed in the paper. 
The paper above summarizes these effects and synthesizes the current
understanding of nutritional effects on adaptations to resistance

"Diet can favorably influence key steps in the pathway of adaptation,
which can optimize adaptations to resistance training. A primary
mechanism via which diet can exert these effects is by providing key
energy substrates (e.g., glucose, amino acids, lipid substrates, etc.)
at precise times and by altering the hormonal environment to favor
anabolism. Resistance exercise substantially elevates protein turnover
and ingestion of essential amino acids before and after exercise
stimulates transport of amino acids into skeletal muscle and protein
synthesis. Although there have been some enlightening studies on the
role of insulin in mediating responses to diet and exercise
interventions, the influence of other hormones (e.g., GH, IGF-I,
testosterone, cortisol) that have potent effects on carbohydrate,
protein, and lipid balance remain unclear. Future studies should
consider how the entire hormonal milieu responds to different diet and
exercise configurations with an emphasis on target tissue effects.
Because most studies are focused on a single outcome (e.g., protein
balance, glycogen resynthesis, body composition, etc.), one challenge
in the future will be to integrate the findings from these varying
perspectives into a unified model. The pathway of adaptation presented
in this article is one example of such a model. Another challenge in
the future will be to match the varying nutritional demands associated
with periodized resistance training programs with periodized diet
strategies. Ultimately, ?timing or cycling? of diet on an hourly,
daily, weekly, or monthly basis to match the unique demands of each
workout or phase of training may enhance adaptations to training."


Dr. Volek also published a review article  (here is the reference):
Volek JS.  Strength nutrition.  Curr Sports Med Rep. 2003 Aug;2(4):189-93. Review.

This may be helpful for a larger overview of nutrition in strength
training.  You might request a copy of this article along with the one
above if you e-mail the author.

Another study, looking at the effects of supplement consumption on
adaptations to resistance training can be found here:

Rankin JW, Goldman LP, Puglisi MJ, Nickols-Richardson SM, Earthman CP,
Gwazdauskas FC.  Effect of post-exercise supplement consumption on
adaptations to resistance training.  J Am Coll Nutr. 2004

Here is a link to the abstract:

The article is available free online from the above link.

This study looked at nutritional manipulations as they affect
enhancement of lean tissue gains stimulated by resistance training. 
This study found no difference in untrained 18-25 year old men for
consumption of milk vs. a carbohydrate-electrolyte drink consumed just
after exercise.


Yet another group, from Texas, reviewed the literature around
carbohydrate supplementation and resistance training.  Here is the
reference and link to the abstract:

Haff GG, Lehmkuhl MJ, McCoy LB, Stone MH.  Carbohydrate
supplementation and resistance training.  J Strength Cond Res. 2003
Feb;17(1):187-96. Review.

Here is the important portion of the abstract:
"Some researchers suggest that ingesting carbohydrate supplements
prior to and during resistance training may improve
resistance-training performance. Additionally, the ingestion of
carbohydrates following resistance exercise enhances the resynthesis
of muscle glycogen, which may result in a faster time of recovery from
resistance training, thus possibly allowing for a greater training
volume. On the basis of the current scientific literature, it may be
advisable for athletes who are performing high-volume resistance
training to ingest carbohydrate supplements before, during, and
immediately after resistance training."

The full version of this article can be requested from Dr. Haff at the
following e-mail address:


Another review can be found in this reference from a group in Canada:

Lemon PW, Berardi JM, Noreen EE.  The role of protein and amino acid
supplements in the athlete's diet: does type or timing of ingestion
matter?  Curr Sports Med Rep. 2002 Aug;1(4):214-21. Review.

The full version of the paper can be requested from Dr. Lemon at this
e-mail address:

This review article is a couple of years older than the one I
discussed in more detail initially, and covers much of the same
information, but may give you a somewhat different point of view. 
Here is the abstract for convenience:

"Rather than the age-old debate regarding overall protein and amino
acid needs of athletes, this paper focuses on the importance of timing
and type of protein and amino acid ingestion relative to both muscle
growth and exercise performance. Evidence discussed comes from
definitive measurement techniques including net protein balance
determinations (for acute studies) or quantification of muscle size or
strength (for chronic studies) First, recent data indicate that
consuming a small meal of mixed macronutrient composition (or perhaps
even a very small quantity of a few indispensable amino acids)
immediately before or following strength exercise bouts can alter
significantly net protein balance, resulting in greater gains in both
muscle mass and strength than observed with training alone. With
aerobic exercise, some evidence suggests immediate postexercise (but
perhaps not pre-exercise) supplementation is also beneficial. Second,
protein type may also be important owing to variable speeds of
absorption and availability, differences in amino acid and peptide
profiles, unique hormonal response, or positive effects on antioxidant
defense. In addition to athletes, many others who desire to regain,
maintain, or enhance muscle mass or function, including those with
muscle-wasting diseases, astronauts, and all of us as we age, need to
ensure that nutrient availability is sufficient during the apparently
critical anabolic window of time associated with exercise training
sessions. Future studies are needed to fine tune these


A more recent article from Canada (the reference and link are below)
discusses more broadly nutritional strategies related to training,
including caffeine, creatine, intramuscular triacylglycerol, etc.

Spriet LL, Gibala MJ.  Nutritional strategies to influence adaptations to training.
J Sports Sci. 2004 Jan;22(1):127-41. Review.

The full version of this article can be requested from the author (Dr.
Spriet) at this e-mail address:

Here is the interesting portion of the abstract:

"...(1) caffeine ingestion; (2) creatine ingestion; (3) the use of
intramuscular triacylglycerol (IMTG) as a fuel during exercise and the
nutritional effects on IMTG repletion following exercise; and (4) the
role nutrition may play in regulating the expression of genes during
and after exercise training sessions. Recent findings suggest that low
doses of caffeine exert significant ergogenic effects by directly
affecting the central nervous system during exercise. Caffeine can
cross the blood-brain barrier and antagonize the effects of adenosine,
resulting in higher concentrations of stimulatory neurotransmitters.
These new data strengthen the case for using low doses of caffeine
during training. On the other hand, the data on the role that
supplemental creatine ingestion plays in augmenting the increase in
skeletal muscle mass and strength during resistance training remain
equivocal. Some studies are able to demonstrate increases in muscle
fibre size with creatine ingestion and some are not. The final two
nutritional topics are new and have not progressed to the point that
we can specifically identify strategies to enhance the adaptation to
training. However, it is likely that nutritional strategies will be
needed to replenish the IMTG that is used during endurance exercise.
It is not presently clear whether the IMTG store is chronically
reduced when engaging in daily sessions of endurance training or if
this impacts negatively on the ability to train. It is also likely
that the increased interest in gene and protein expression
measurements will lead to nutritional strategies to optimize the
adaptations that occur in skeletal muscle during and after exercise
training sessions. Research in these areas in the coming years will
lead to strategies designed to improve the adaptive response to


Although somewhat dated, the official Guideline report from the
American Dietetic Association, Dietitians of Canada, and the American
College of Sports Medicine on nutrition and athletic performance
remains a useful guide for general nutrition for athletes.

Here is the abstract, which contains the major points of the guidelines:

"It is the position of the American Dietetic Association, Dietitians
of Canada, and the American College of Sports Medicine that physical
activity, athletic performance, and recovery from exercise are
enhanced by optimal nutrition. These organizations recommend
appropriate selection of food and fluids, timing of intake, and
supplement choices for optimal health and exercise performance. This
position paper reviews the current scientific data related to the
energy needs of athletes, assessment of body composition, strategies
for weight change, the nutrient and fluid needs of athletes, special
nutrient needs during training, the use of supplements and nutritional
ergogenic aids, and the nutrition recommendations for vegetarian
athletes. During times of high physical activity, energy and
macronutrient needs--especially carbohydrate and protein intake--must
be met in order to maintain body weight, replenish glycogen stores,
and provide adequate protein for building and repair of tissue. Fat
intake should be adequate to provide the essential fatty acids and
fat-soluble vitamins, as well as to help provide adequate energy for
weight maintenance. Overall, diets should provide moderate amounts of
energy from fat (20% to 25% of energy); however, there appears to be
no health or performance benefit to consuming a diet containing less
than 15% of energy from fat. Body weight and composition can affect
exercise performance, but should not be used as the sole criterion for
sports performance; daily weigh-ins are discouraged. Consuming
adequate food and fluid before, during, and after exercise can help
maintain blood glucose during exercise, maximize exercise performance,
and improve recovery time. Athletes should be well-hydrated before
beginning to exercise; athletes should also drink enough fluid during
and after exercise to balance fluid losses. Consumption of sport
drinks containing carbohydrates and electrolytes during exercise will
provide fuel for the muscles, help maintain blood glucose and the
thirst mechanism, and decrease the risk of dehydration or
hyponatremia. Athletes will not need vitamin and mineral supplements
if adequate energy to maintain body weight is consumed from a variety
of foods. However, supplements may be required by athletes who
restrict energy intake, use severe weight-loss practices, eliminate
one or more food groups from their diet, or consume high-carbohydrate
diets with low micronutrient density. Nutritional ergogenic aids
should be used with caution, and only after careful evaluation of the
product for safety, efficacy, potency, and whether or not it is a
banned or illegal substance. Nutrition advice, by a qualified
nutrition expert, should only be provided after carefully reviewing
the athlete's health, diet, supplement and drug use, and energy


As implied in the Guidelines report above, another consideration is
that a body builder doesn't want to enter a catabolic state.  In other
words, starving yourself all day, and only eating after lifting, may
be counterproductive if taken to the extreme.  At some point, the body
requires both energy and raw materials to function.  If it's not
receiving this from the gut, then it will get it from fat, glycogen,
muscle, etc.

The full version of this Guideline report can be found here:


Most of the web resources, books, etc., are in some way, it seems,
linked back to the scientific studies done on nutrition and weight
lifting cited by the articles above.  In some cases, the results are
faithfully reproduced in the proper context.  Most of the time,
however, the results are either overstated or extrapolated beyond what
is reasonable.

That being said, some web resources that may also be of interest follow:

From Dr. John Berardi (Ph.D.), a two-part article on nutritional
timing that has numerical references, but no actual bibliography of
references.  I would bear in mind that Dr. Berardi has also published
a nutrition book and has a vested interest in selling his ideas.  Here
are the links:

Yet another site advocates carbohydrate replenishment before, during,
and after exercise.  Here is a link to an article on this method by
Dr. James Meschino D.C., M.S.:

Other articles from this site on nutrition can be found here:

This article from Muscle & Fitness/Hers (August, 2004) by Martica
Heaner discusses some of the studies done on nutritional timing for
women athletes and is a somewhat better source of information, but is
short on specifics.


A useful Google search for finding websites:
"weight lifting" nutrition timing

I also recommend trying this search on the beta Google site:
This tool makes finding scientific and scholarly research articles
easier.  Obviously, these tend to be more credible.

I hope this information was helpful.  Please remember that every
individual is different and no nutritional or lifting regimen will
work for everyone.

Please do not hesitate to request any clarification.



Request for Answer Clarification by donphiltrodt-ga on 11 Apr 2005 17:31 PDT
Rats.  I can't post a comment.  This is not actually a "request for clarification".

I highly value your research and synthesis skills.  Can I use you to
research other non-health related topics?  (e.g. software usability,
artificial intelligence, analysis of "popular opinion" from forums,
lists and blogs for a variety of topics) If I post a question in other
areas, will you see it?

Clarification of Answer by welte-ga on 11 Apr 2005 19:01 PDT
Thanks for your generous tip, comments, and ratings.  You can post
questions in any area with something like "for welte-ga" in the
subject line.  I periodically search for such questions and usually
try to scan new questions every couple of days.  If a question is too
far outside my area of expertise, I'll let you know.


donphiltrodt-ga rated this answer:5 out of 5 stars and gave an additional tip of: $10.00
This is an utterly stellar answer.

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