A HOUSE OF PROTEINS 31showing that "low-quality" plant protein, which allows for slow but
steady synthesis of new proteins, is the healthiest type of protein. Slow
but steady wins the race. The quality of protein found in a specific food
is determined by seeing how fast animals would grow while consuming
it. Some foods, namely those from animals, emerge with a very high
protein efficiency ratio and value.^1
This focus on efficiency of body growth, as if it were good health, en-
courages the consumption of protein with the highest "quality." As any
marketer will tell you, a product that is defined as being high quality
instantly earns the trust of consumers. For well over 100 years, we have
been captive to this misleading language and have oftentimes made the
unfortunate leap to thinking that more quality equals more health.
The basis for this concept of protein quality was not well known
among the public, but its impact was-and still is-highly significant.
People, for example, who choose to consume a plant-based diet will
often ask, even today, "Where do I get my protein?" as if plants don't
have protein. Even if it is known that plants have protein, there is still
the concern about its perceived poor quality: This has led people to
believe that they must meticulously combine proteins from different
plant sources during each meal so that they can mutually compensate
for each other's amino acid deficits. However, this is overstating the
case. We now know that through enormously complex metabolic sys-
tems, the human body can derive all the essential amino acids from the
natural variety of plant proteins that we encounter every day. It doesn't
require eating higher quantities of plant protein or meticulously plan-
ning every meal. Unfortunately, the enduring concept of protein quality
has greatly obscured this information.THE PROTEIN GAP
The most important issue in nutrition and agriculture during my early
career was figuring out ways to increase the consumption of protein,
making sure it was of the highest possible quality: My colleagues and I
all believed in this common goal. From my early years on the farm to my
graduate education, I accepted this virtual reverence for protein. As a
youngster, I remember that the most expensive part of farm animal feed
was the protein supplements that we fed to our cows and pigs. Then,
at graduate school, I spent three years (1958-1961) doing my Ph.D. re-
search trying to improve the supply of high-quality protein by growing
cows and sheep more efficiently so we could eat more of them. 2 .3