2: The Origin of the Low-Fat, High-Carbohydrate Diet

If you saw a book cover entitled “Pure, White, and Deadly,” you’d likely think the book was about cocaine or heroin. But in 1972, Dr. John Yudkin, a medical doctor and a professor of Nutrition and Dietetics at the University of London, published a book with that exact title…a book that warned that the increasing consumption of sugar was closely associated with coronary heart disease and Type II diabetes. Studies Dr. Yudkin had been conducting for 15 years indicated that sugars and starches raised blood triglycerides and insulin levels. Dr. Yudkin warned that a diet high in carbohydrates was directly linked to what we now call the “metabolic syndrome”– obesity, diabetes, high blood pressure, cholesterol imbalances, and cardiovascular disease.  In Yudkin’s studies, fat played little or no role as the cause of metabolic syndrome.

In 1980, Ansel Keyes, an American epidemiologist and statistician, published the Seven Countries Study, which showed a correlation between cholesterol and cardiovascular disease in the populations of seven different nations. Keyes argued that the rise of serum cholesterol in countries such as England, the United States, Australia and Canada could be directly correlated to a rise in the consumption of dietary fat in these countries, and that the rise of such dietary fat consumption could therefore be linked to the rise of coronary artery disease. His findings were quickly embraced by the Department of Agriculture, the American Medical Association, and the American Heart Association.

Two years later, the USDA published new dietary guidelines encouraging a decrease in the consumption of dietary fats, while encouraging increased consumption of high-sugar carbohydrates such as grains, breads, and pastas. Ansel Keyes’ dietary recommendations had been officially vetted and approved by the United States government, and the “low-fat, high-carb” diet craze was on.  America’s (and the world’s) sugar consumption rose dramatically.

What has been the result of an entire society following Keyes dietary guidelines over the past 30 years?

According to the Center for Disease Control, metabolic syndrome is up 26% since 1988, and for the first time is increasing in overweight adolescents. Americans are now getting almost 25% of their daily caloric intake from sugar. As UCSF neuroendocrinologist Dr. Robert Lustig says in his lecture, Sugar: The Bitter Truth, “Fat’s are going down, sugar is going up, and we’re all getting sick.”

How did Keyes get it so wrong?  He failed to test the effects that increased sugar consumption was already having in the diets of the industrialized nations he tested.  Keyes was also accused of “skewing” his results to favor his hypothesis: while he accumulated data from 22 countries, he reported the results of only 7, leaving out the high-fat diets of countries like France, Switzerland, Iceland, and Austria that showed no increase in cardiovascular disease in correlation to their consumption of dietary fat.

Keyes never isolated sugar from his results– in other words, Keyes failed to test a control group that ate just high fats without increased sugar.  So while Keyes was attributing metabolic syndrome results to an increase in dietary fat, what many now postulate was really causing his results was the high concentrations of sugar already present in the industrialized diets that accompanied the fats.

As America (and much of the world) embraced Keyes’ dietary findings, fat consumption has dropped and sugar consumption has soared, especially consumption of a new, man-made sugar called “high-fructose corn syrup.”

In 1975, an industrially engineered sweetener came to the United States. Manufactured by an enzyme process developed in Japan by Dr. Y. Takasaki, this new inexpensive sweetener– called high-fructose corn syrup, or HFCS– converted the glucose of ordinary corn syrup into a much sweeter fructose sugar. As a result, companies that used cane or beet sugar (sucrose) in their products could now buy cheaper high-fructose corn syrup, and save even more money by having to use less of it in their recipes. Within 2-3 years, the sweeter and cheaper HFCS was being used in soft drinks, breads, cakes, peanut butter, ketchup, pastries, candies, breakfast cereals, pastas, juice drinks, and even baby formula.  By the mid-1980’s, HFCS was present in 50% of all the processed foods manufactured in the U.S.

Interestingly, before the introduction of HFCS, human beings had very little dietary exposure to fructose. Fructose in nature was mostly limited to fruits, honey, dates, raisins, grapes, and apples and thus consumed in small quantities.  With the introduction of HCFS, many scientists expressed concern that while glucose could be metabolized by every living cell in the body, fructose could only be metabolized by the liver,  and therefore the long-term effect of increased fructose exposure was unknown.  Yet, the USDA– without any studies– adopted the position put forth by the American Beverage Council and the National Corn Growers Association that HFCS was essentially a “similar sugar” that was being swapped for an existing sugar and therefore required no regulation.

The effect on sugar consumption has been dramatic.

In 1970, the per capita consumption of sugar in the United States was 73 pounds a year. In 1999, the USDA reported that number had increased to 146 pounds a year, of which 65 pounds was comprised of high-fructose corn syrup.  By 2010, annual per capita sugar consumption had risen to 160 pounds of sugar per year, of which 96 pounds was comprised of high-fructose corn syrup…almost half a pound of pure sugar per day for every man, woman, and child in the United States.

By comparison, in 1800, the average American only consumed about 18 pounds of sugar a year. The rise of sugar consumption over just the past three decades in the United States and around the world represents the largest, most drastic dietary change in the history of mankind.

Had Keyes isolated the sugar and tested for its effects without dietary fat, he would have discovered what we now know…that John Yudkin’s 1972 treatise on the dangers of sugar was correct. High levels of sugars and starches, not dietary fats, are the major cause of the medical disorders present in the metabolic syndrome.

Why haven’t we corrected this mistake?  U.S. industry currently exports billions of dollars of soft drinks and fast food around the globe– both products which use high levels of sugar as an integral part of their consumer demand, formulation, and profit. Breakfast cereals, which also rely heavily on sugared products, generate $6.5B in annual sales. Sugar production alone is a $10B industry in the United States.

The corn, food, and beverage industries spend millions of dollars a year lobbying congress to protect their interests, and have launched numerous public relations campaigns to convince the public that sugar– including HFCS– is healthy (see www.sweetsurprise.com, a website sponsored by the Corn Growers Association).  Currently, in an attempt to deal with consumers’ new reluctance to eat HFCS, the corn industry has a petition before the FDA to allow food and beverage labels to substitute the term “corn sugar” for the current “high-fructose corn syrup” name.

Institutional changes and beliefs happen slowly.  Companies are banning trans fats and eliminating HFCS from foods in response to consumer demand, and consumers are becoming more aware of the dangers of sugar.  I believe this trend will only continue. But getting sugar out of our individual diets is something each of us can begin to do right now, by eating a low-glycemic diet.

Next article: The Low-Glycemic Diet

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