Protein
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1. Are all proteins the same?
No. Fruit, vegetables, grains, and legume / bean protein sources are slightly low in
a couple amino acids. Soy (a legume) is the most complete protein of these, but its
slight deficiency in methionine requires that ~5% more soy be eaten than meat, dairy,
or fish sources in order to maintain nitrogen balance. Five percent is not a lot, so you
can pretty much assume that soy is complete. Grains and vegetables compliment
legumes and beans so that including a source of each (grain or vegetables as well as
either legumes / soy or beans) results in your getting a complete amino acid profile.
The American College of Sports Medicine has issued a “position statement” regarding
complimentary proteins stating that it is not important to eat plants and legumes
together to get complete protein. If you look at their scientific references, however, you
will see that both animals and human children have had increased protein breakdown
in their body (negative nitrogen balance) when complimentary proteins are not eaten
together. They ignore this and conclude that adults need not eat complimentary
proteins together because no experiments have actually been done in adults. I
disagree with their conclusion. Proteins from dairy, meat, and fish are equivalent to
each other and are complete on their own.. Protein powders (including soy, which is
the only legume nearly complete in its amino acids relative to our needs) are
equivalent to each other. Isolates (as opposed to concentrates) are more pure, more
easily digested, and more soluble in water.
2. What are BCAAs?
Branched Chain Amino Acids. These are the three amino acids (leucine, isoleucine,
and valine) that have a branch in their molecular structure. These amino acids are the
easiest for the body to convert into glucose (the sugar used by the body as fuel) and
constitute ~1/4 of the amino acids in the proteins of your muscles. When the body is
low in carbohydrate fuel, it breaks down muscle tissue to burn amino acids. The BCAAs
are consumed first since they are burned the easiest). Although, theoretically,
supplementing with BCAAs should trick the body into not breaking down its own
muscle, scientific studies have shown only modest reductions in muscle protein
breakdown with amino acid supplementation during training. My personal opinion is
that an athlete should stay on the safe side and supplement with some protein (BCAAs
if you prefer, but not necessarily). There is no evidence that taking more than 15 g of
BCAAs or 50 g of whole protein (powder) during training results in any additional
positive benefit beyond the mild benefits given by these levels of intake (see Article
#1). In summary, some protein intake during training, whether in the form of BCAAs or
protein powder, will help you spare muscle tissue to a small extent. It is therefore worth
the effort of including some protein, but not worth the effort of including a lot since you
will just slow down your digestion, possibly get stomach cramps, and unnecessarily
elevate your blood amino acid concentration. High amino acid concentration in the
blood has been shown to reduce the rate of sugar intake into muscle [Tremblay F and
Marette A, J Biol Chem, 41 2001 38052; Krebs M et al, Diabetes, 51 2002 599].
No. Fruit, vegetables, grains, and legume / bean protein sources are slightly low in
a couple amino acids. Soy (a legume) is the most complete protein of these, but its
slight deficiency in methionine requires that ~5% more soy be eaten than meat, dairy,
or fish sources in order to maintain nitrogen balance. Five percent is not a lot, so you
can pretty much assume that soy is complete. Grains and vegetables compliment
legumes and beans so that including a source of each (grain or vegetables as well as
either legumes / soy or beans) results in your getting a complete amino acid profile.
The American College of Sports Medicine has issued a “position statement” regarding
complimentary proteins stating that it is not important to eat plants and legumes
together to get complete protein. If you look at their scientific references, however, you
will see that both animals and human children have had increased protein breakdown
in their body (negative nitrogen balance) when complimentary proteins are not eaten
together. They ignore this and conclude that adults need not eat complimentary
proteins together because no experiments have actually been done in adults. I
disagree with their conclusion. Proteins from dairy, meat, and fish are equivalent to
each other and are complete on their own.. Protein powders (including soy, which is
the only legume nearly complete in its amino acids relative to our needs) are
equivalent to each other. Isolates (as opposed to concentrates) are more pure, more
easily digested, and more soluble in water.
2. What are BCAAs?
Branched Chain Amino Acids. These are the three amino acids (leucine, isoleucine,
and valine) that have a branch in their molecular structure. These amino acids are the
easiest for the body to convert into glucose (the sugar used by the body as fuel) and
constitute ~1/4 of the amino acids in the proteins of your muscles. When the body is
low in carbohydrate fuel, it breaks down muscle tissue to burn amino acids. The BCAAs
are consumed first since they are burned the easiest). Although, theoretically,
supplementing with BCAAs should trick the body into not breaking down its own
muscle, scientific studies have shown only modest reductions in muscle protein
breakdown with amino acid supplementation during training. My personal opinion is
that an athlete should stay on the safe side and supplement with some protein (BCAAs
if you prefer, but not necessarily). There is no evidence that taking more than 15 g of
BCAAs or 50 g of whole protein (powder) during training results in any additional
positive benefit beyond the mild benefits given by these levels of intake (see Article
#1). In summary, some protein intake during training, whether in the form of BCAAs or
protein powder, will help you spare muscle tissue to a small extent. It is therefore worth
the effort of including some protein, but not worth the effort of including a lot since you
will just slow down your digestion, possibly get stomach cramps, and unnecessarily
elevate your blood amino acid concentration. High amino acid concentration in the
blood has been shown to reduce the rate of sugar intake into muscle [Tremblay F and
Marette A, J Biol Chem, 41 2001 38052; Krebs M et al, Diabetes, 51 2002 599].
© Clyde F. Wilson