Part 3 in a series of posts adapted from my paper, "Modern Health, Primitive Wisdom: American Health History and the Findings of Weston A. Price."
Over a hundred years, we have conquered tuberculosis and pneumonia, improved safety measures in work environments, developed methods to increase food supply, and improved infant survival rates. Yet the quality of our lives is now diminished through conditions such as diabetes, heart disease, and cancer. These changes in disease patterns over the last century correlate strongly with changes in diet. Aside from an increase in processed food consumption since the early 1900s, our consumption of fats and oils has shifted quite dramatically in terms of quality (not so much quantity, contrary to popular belief). In other words, the type of fats (animal, fruit, and vegetable) and specific fatty acids (saturated, monounsaturated, and polyunsaturated) that Americans ate one hundred years ago were very different from those that are eaten today. The table below provides an overview of the changes that have taken place.
Much of the fats that Americans have eaten for centuries -- and that many traditional cultures have eaten for thousands of years -- have been mostly saturated and monounsaturated. Animal fats top the list in 1890 as the fat of choice for cooking, baking, and spreading. Yet, heart disease (commonly believed to be caused by animal fat consumption) was far less prevalent during this era. In 1990, we see vegetable oils are leading the way, while animal fat consumption is so minimal that it does not make the list. For the first time in history, people are ingesting large amounts of polyunsaturated oils extracted from seeds and grains. These oils are often unknowingly eaten in prepackaged foods, as they are the oil of choice for the modern food industry due to their cost-effectiveness. Most potato chips, for example, use corn, canola, or soybean oils -- none of which were consumed in significant amounts by our ancestors.
As the type of fats and oils that the United States consumes has changed in the last 100 years, degenerative diseases have became more and more common. Saturated fat consumption has been blamed for causing many modern diseases. Modern Americans are claimed to be eating too much saturated fat and have been encouraged to cut back as much as possible to prevent disease. Is saturated fat to blame? If it were, one would expect the consumption of saturated fat to have increased substantially since the early century. This has not been the case, however:
Over the course of the 19th century, as heart disease has increased and cancer has become a common cause of death in the United States, saturated fat consumption has remained quite stable. Monounsaturated fat consumption has increased substantially. Yet this change pales in comparison to the growing popularity of polyunsaturated fat in the American diet. In the 1950s, with polyunsaturated vegetable oils gaining favor by the edible oil industries (whose primary motivation was to make a profit), Americans began eating more and more of these unnatural, man-made fats -- fats which were traditionally only consumed as whole foods, such as grains, vegetables, seeds, and nuts.
In her book, American Food Habits in Historical Perspective (1995), Elaine N. McIntosh states: "Essentially, the consumption of animal fat has declined since 1940, and the consumption of vegetable oils has increased steadily since 1909, overtaking animal fats in 1950" (p. 210). The transition from a diet rich in saturated and monounsaturated fatty acids (mostly from animal fats) to a diet high in polyunsaturated fatty acids (vegetable oils -- many of which are hydrogenated trans fats) has been one of the most significant changes in human nutrition in the past 100 years.
Source for above tables:
Enig, Mary G. (2000). Know Your Fats : The Complete Primer for Understanding the Nutrition of Fats, Oils and Cholesterol. Silverspring, MD: Bethesda Press
Next, Part 4: "What About Cholesterol?"