BROKEN HEARTS 119In 1946, when this study began, most scientists believed that heart
disease was an inevitable part of aging, and nothing much could be done
about it. While Morrison didn't cure heart disease, he proved that some-
thing as simple as diet could significantly alter its course, even when the
disease is so advanced that it has already caused a heart attack.
Another research group proved much the same thing at about that
time. A group of doctors in Northern California took a larger group of
patients with advanced heart disease and put them on a low-fat, low-
cholesterol diet. These doctors found that the patients who ate the low-
fat, low-cholesterol diet died at a rate four times lower than patients who
didn't follow the diet.^23
It was now clear that there was hope. Heart disease wasn't the inevi-
table result of old age, and even when a person had advanced disease, a
low-fat, low-cholesterol diet could significantly prolong his or her life.
This was a remarkable advance in our understanding of the number one
killer in America. Furthermore, this new understanding made diet and
other environmental factors the centerpieces of heart disease. Any dis-
cussion of diet, however, was narrowly focused on fat and cholesterol.
These two isolated food components became the bad guys.
We now know that the attention paid to fat and cholesterol was mis-
guided. The possibility that no one wanted to consider was that fat and
cholesterol were merely indicators of animal food intake. For example,
look at the relationship between animal protein consumption and heart
disease death in men aged fifty-five to fifty-nine across twenty different
countries in Chart 5.3.^16
This study suggests that the more animal protein you eat, the more
heart disease you have. In addition, dozens of experimental studies
show that feeding rats, rabbits and pigs animal protein (e.g., casein)
dramatically raises cholesterol levels, whereas plant protein (e.g., soy
protein) dramatically lowers cholesterol levels. 24 Studies in humans not
only mirror these findings, but show that eating plant protein has even
greater power to lower cholesterol levels than reducing fat or choles-
terol intake.^25
While some of these studies implicating animal protein were con-
ducted in the past thirty years, others were published well over fifty
years ago when the health world was first beginning to discuss diet and
heart disease. Yet somehow animal protein has remained in the shadows
while saturated fat and cholesterol have taken the brunt of the criticism.
These three nutrients (fat, animal protein and cholesterol) characterize