The Hormone That Cried Wolf

Gary Taubes wrote an interesting article in the New York Times. He outlines the studies indicating that excess sugar consumption  leads to fatty liver, insulin resistance,  obesity, diabetes, heart disease, and some cancers. He queries his way through the evidence to try to answer the question, “Is sugar toxic?”

First of all, let’s start out with some facts:

1. Taubes establishes that refined sugar (sucrose) is a 50-50 mixture of fructose and glucose. Fructose is what makes sugar sweet, which might partly explain the popularity of high fructose corn syrup, which is 55% fructose and 45% glucose. So  the maligned high fructose corn syrup is only 5% higher in fructose content than regular refined sugar.

2. It’s important to know that the body metabolizes fructose and glucose differently: the liver processes fructose, and every cell in the body processes glucose.  Complex carbs (rice, bread) are broken down into glucose.  The more fructose one consumes, and the smaller amount of time one consumes it in (say if it’s in a drink), then the harder the liver has to work.

3. The pancreas secretes insulin to respond to foods that raise our blood sugar, namely carbohydrates and sugars. The insulin scoops the excess sugar from our bloodstream and stores it in the liver and muscles in the form of glycogen. But if the reserves are full or too much sugar was consumed, the cells begin to ignore insulin.  The exhausted pancreas needs to pump out more insulin to get the same effect, and and the sugar is eventually stored in fat cells.

4. The process described above is called insulin resistance. To restate, this is when the pancreas cannot secrete enough insulin to manage rising blood sugar levels because the cells become resistant to insulin. Consequently,  the excess sugar and insulin remain in the blood stream for longer.  Chronic insulin resistance is also known as metabolic syndrome.

5. More and more evidence is linking sugar consumption with insulin resistance.

6. Insulin resistance and chronically elevated insulin levels are accepted as a significant risk factor (if not a precursor) to diabetes, obesity,  high blood pressure, low HDL cholesterol levels (the “good cholesterol”), and high triglycerides.

7. The World Health Organization’s International Agency for Research on Cancer studied large populations in 2004. Their findings state one is more likely to get cancer if they are insulin resistant, obese, and/or diabetic. Other researchers are finding this as well.

8. Furthermore, cancer researchers are finding that excess insulin (a symptom of insulin resistance) promotes tumor growth, and the cells of several human cancers need insulin for fuel/blood sugar. Insulin resistance seems to be at the center of several cumulative diseases.

9. Researchers currently studying insulin resistance assert that the accumulation of fat in the liver (fatty liver disease) is the likely cause of insulin resistance. Accumulation of fat  in the liver. According to the second point listed above, the liver processes fructose. So what causes fat to accumulate in the liver? Is it sugar, fructose consumption in particular? Yes, yes it is.

And if one were to look at the facts from a bird’s eye view, this would appear to be the case. For example, in the 1980’s, each American was consuming an average of 75 pounds of sugar per year (according to the USDA). One in seven were obese and 6 million were diabetic. Sugar consumption per person increased to 90 pounds a year in the early 2000’s. By then, one in every three were diabetic, and 14 million were diabetic.

The Centers for Disease Control and Prevention now estimate that 75 million Americans have metabolic syndrome. The information below is from the Centers for Disease Control and Prevention:

Unfortunately, while there is plenty of similar “circumstantial evidence” correlating sugar consumption to obesity and diabetes. The National Institutes of Health aren’t funding many viable studies that produce conclusive results. Taubes points out the flaws in several of the studies relating sugar consumption to insulin resistance:

  • There are studies that link consuming beverages sweetened with fructose to insulin resistance; however, refined sugar is half fructose and half glucose.
  •  The dosages used are perhaps too high (8-10 cans of Coke a day).
  • Insulin resistance, heart disease, and diabetes require several months to several years to develop. One meal or a few weeks’ worth of meal studies aren’t enough to establish whether or not  it is a culprit.

One reason why there has been so little attention given to sugar’s effects is because the people asserting that sugar is toxic are also advocating that saturated fat is harmless. In the 1970’s scientist John Yudkin did just this, and his work was not taken seriously because of the increasing prevalence of anti-fat biases. Dr. Atkins faced similar criticisms. Yet the fact remains that,trans fats aside, fat intake does not result in insulin resistance.

America has been quite busy with demonizing fat that it seems to have not noticed the elephant in the room: sugar. Sadly, as a result, we have little conclusive, time-tested evidence to portray sugar accurately to the general public. Thus the cycle continues: people continue to see fat as the bad guy while downing the insulin-producing sugars.

 However, Tabues is not asserting that just because many scientists have failed to exercise objectivity means we should passively wait around for them to do their jobs:

If sugar just makes us fatter, that’s one thing. We start gaining weight, we eat less of it. But we are also talking about things we can’t see–fatty liver, insulin resistance, and all that follows. Officially, I’m not supposed to worry because the evidence isn’t conclusive, but I do.

Keeping sugar intake to a minimum, watching how you feel, and keeping track of your stats (weight, blood pressure, cholesterol, triglycerides, thyroid function) is the most important research you can do.

Furthermore, plain old common sense helps. Insulin is at the center of it all. Sugar and carbohydrate consumption triggers insulin secretion; fat consumption does not. Chronically elevated insulin leads to diabetes, weight gain, high blood pressure, lower HDL cholesterol, metabolic syndrome, and even cancer. These are facts, and you can act accordingly.

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One response to this post.

  1. Posted by JB on May 2, 2011 at 5:58 pm

    Excellent writeup, love. You ought to email a link to mister Taubes.

    Maybe you could help me brainstorm on ways to reduce my sugar? Breakfast would be a good place to start. And good snack options.

    I think this is one of your best posts yet. When coming down on conventional wisdom, I believe it helps to avoid sounding condescending or utterly appalled at the establishment, which you’ve achieved here. Good work! 🙂

    Reply

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