The Origins Of The Low Fat Diet Push
How Misguided Food Labeling Led To Our Consumption Of Trans-Fats
Soy's LimitationsThere are, however, issues with soybean oil. It has properties that make it unsuitable as a simple substitute for animal and tropical fats in various applications (if you are interested there is a short course on the chemistry of oils and fats at the end of this post). It couldn’t be used to make a substitute for stick butter because it was liquid at room temperature. Soybean oil was also poorly suited for deep fat frying applications because it didn’t have the necessary “fry life” to fit in the burgeoning fast-food industry of that time. After a relatively short period of high temperature cooking, it would develop off-tastes. In other products it tended to turn rancid faster that other alternatives.
Between low cost and these positive-sounding messages, hydrogenated soybean oil found its way into a host of foods in the US diet. When mandatory nutrient content labeling was established in 1990, Congress failed to fund the education component envisioned in the bill. Thus, the official "back label" only served to further propel the sales of various fat-avoidance products and trans-fats, and did nothing to stem the disinformation on the front, marketing-oriented labels.
Early on, the substitutions being made by these commercial entities were done with confidence that they were a good thing. Unfortunately, that was not true.
The Solution Becomes The Problem
What Should We Learn From This?
So, did we learn from the low fat marketing experience? Seemingly not much. Instead we have continued down the path of magical thinking about food. We go through fad after fad about what single bad actor ingredient to avoid or what magical good component to eat, somehow believing that these simplistic formulas can put us on the path to health. The press, various celebrities and "experts" are often guilty of over-selling such ideas as they emerge incompletely formed from the fields of nutrition or medicine. Well-meaning or simply opportunistic food marketers are then more than willing to follow or even promote each fad. I call that "the marketing of non-existance." We continue to be sold new non-existence options such as “Low Carb,” “no High Fructose Corn Syrup,” “Gluten-Free,” and “non-GMO.” These are dietary strategies based on the mindset that foods are something to be feared or at least viewed with suspicion.
These fads distract us from the fundamental healthy diet principles of moderation and diversity. They distract us from the fact that the most dramatic way that most Americans could improve their health prospects would be to consume more fruits and vegetables. Perhaps its time to start buying what we eat for what it is as a whole food, not for what it is not.
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A Short Course About Oils And Fats
What makes the various fats and oils different from one another is what kind of fatty acids they contain.Fatty acids are chains of carbon atoms with a polar carbonyl group at one end. They differ in the length of the chain and in how many double bonds there are between the carbons.
As shown above, the dominant fatty acid in animal fats is stearic acid with 18 carbons and no double bonds (saturated). Oleic acid which is a major component of olive oil or modern Canola and Sunflower oil also has 18 carbons, but has one double bond (mono-unsaturated). Linolenic acid was one of the problematic components of soybean oil which needed to be fixed by partial hydrogenation. It has 18 carbons and three double bonds (poly-unsaturated). "Tropical oils" are generally shorter chained - Palm oil has mostly 14 carbon amino acids and coconut oil has mostly chains of 12 carbons.
The cis- and trans- fats differ in the orientation of the hydrogen atoms (white) attached to the carbon atoms (black) that are connected by a double bond. The normal cis- configuration has both hydrogens on the same side of the chain. The trans- configuration has the hydrogens on the opposite side of the chain and this gives the fatty acid a different bend and influences its fluid properties when it is part of a membrane. There are some natural trans-fats, particularly in meat and milk from ruminants because rumen bacteria convert unsaturated fats to saturated forms, going through some trans- intermediates along the way. There are actually health benefits associated with the production of Conjugated Linoleic Acid (CLA) in this process.