Saturday, May 9, 2009

Big, Fat Changes in American Foods

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?"

4 comments:

Stephan said...

Nice one. The comparison between sources of fat is really striking. Most of the fat they ate in 1890 was "paleo". I suppose butter was a luxury item for most people. I'm going to put your blog in my links.

Stephan

Ryan Koch said...

Yup. Good old lard was the most utilized fat in 1890 -- pretty practical fat when you think of the gobs of the stuff that comes from a single pig. During that time, it would be more common to spread lard on bread than butter!

Thanks for adding me to your links, Stephan -- greatly appreciated!

Dana Seilhan said...

Coming in late on this but the irony of using lard as a spread is that it is actually mostly monounsaturated fat. Read the nutrition label for lard versus the one for butter sometime. It's enlightening. I began cooking with lard several months ago and slowly came to the realization that I didn't have to let it warm to room temperature in order to scoop it out of the tub. Butter, on the other hand, is useless at fridge temperature unless you will immediately be melting it or cooking with it.

Gary Taubes says lard has the same kind of monounsaturated fat present in olive oil. How it ever came to be seen as unhealthy, I have no idea. I can only attribute it to food marketing, which should never have been confused with science.

I remember it being presented to me when I was a kid that saturated fat is bad for you and clogs arteries because it is solid at room temperature. It never occurred to me then that if a human being were room temperature, saturated fat would be the least of his or her worries. Then again, at the time I didn't know what the proper definition of "room temperature" was, and I suspect my teachers and the media didn't know either.

Ryan Koch said...

Dana,

Lard is certainly wonderful stuff. Check out the first table on the post, and you'll see that many of the fats -- not just lard -- that Americans consumed at the turn of the century were very monounsaturated.

Funny stuff about the "room temperature" stuff! I never thought of it like that -- really makes the mainstream nutrition folks look silly. Nice one!