Sunday, August 2, 2009
Although the effects of eating various foods or supplements pre-workout and its effects on LBM are unclear, recent data suggests nutrients taken im- mediately before or during exercise may also play an important role. One recent study found that pre-exercise nutrition had an even greater impact than eating post-workout. The study was designed to determine whether consumption of an oral amino acid-carbohydrate supplement be- fore exercise would result in a greater anabolic response than supplemen- tation after resistance exercise.
Six subjects participated in two trials in random order. The amino-carb mix
consumed immediately before exercise or the same amino-carb drink con-
sumed immediately after exercise. Blood and muscle phenylalanine (an
amino acid) concentrations were increased by approximately 130% after
drink consumption in both trials. Blood levels of phenylalanine during ex-
ercise increased dramatically and remained elevated for two hours after
exercise in both trials.
What was interesting however was the delivery of amino acids was sig-
ni cantly greater when they took the amino-carb mixture pre-workout vs.
when they ingested the amino-carb drink after exercise.
These researchers concluded:
“...these results indicate that the response of net muscle protein synthesis to
consumption of an amino acid and carbohydrate solution immediately before
resistance exercise is greater than that when the solution is consumed after ex-
ercise, primarily because of an increase in muscle protein synthesis as a result
of increased delivery of amino acids…”
A more recent series of studies examined the effects of consuming either
carbohydrate, protein, or a combination of the two during resistance ex-
ercise. The researchers found that combined consumption of carbs and
essential amino acids (EAAs) signi cantly reduced post-exercise cortisol
levels, and reduced excretion of 3-methylhistidine - a marker of protein ca-
tabolism - for up to 48 hours post-workout. In a second paper, the same
group also reported greater increases in cross-sectional area of Type I, IIa,
and IIb muscle bers in the group receiving both the carbs and EAAs.
So what’s the take-home lesson?
The best solution is probably to do both: consume some carbs and protein
immediately before, or during your workout, and then after your workout
is complete. We know from previous work that there are additive effects
when more than one dose of amino acids and carbs are consumed, so it
makes sense to cover all the bases.
This approach is also recommended by researchers John Ivy and Robert
Portman in their recent book “Nutrient Timing”. In their book, they divide
the muscle growth cycle into three distinct phases: the “Energy Phase” (e.g.,
immediately prior to, and during the workout); the “Anabolic Phase: (e.g.,
the 45 minute period following the workout); and the “Growth Phase” (e.g.
the subsequent hours of the day). They present compelling evidence that
the right mixture of nutrients, taken at key points in the muscle growth
cycle, will optimize improvements in muscle growth, strength, and power,
as well as enhance recovery from exercise.
Combining pre- and post-workout nutrition received some very recent, ex-
perimental con rmation. The 10 week study by Dr. Paul Cribb compared
pre- and post-workout carbs, protein and creatine consumed by a group of
resistance-trained men, to a group taking the same nutrients at other times
of the day. Improvements in strength and lean mass were greater in the
group receiving the pre- and post-workout feedings. The study conclud-