Everything You Know About Sugar Is Wrong

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With one of the major eating festivals on the horizon, Childhood Obesity News looks to Scientific American’s Ferris Jabr for information on the toxicity (or not) of sugar. This topic also fits into the “everything you know is wrong” niche for contested theories, which seem to be particularly abundant in the field of obesity. As we have seen, a large number of health professionals are against sugar in any form, assigning it responsibility for the obesity epidemic, the rise in cardiovascular disease, and the surge in Type 2 diabetes and other metabolic disorders. However, there is contrary evidence. Jabr examined a 2011 study in which a team analyzed data collected from 25,000 Americans, noting:

They did not find any positive associations between fructose consumption and levels of trigylcerides, cholesterol or uric acid, nor any significant link to waist circumference or body mass index (BMI).

This result surprises no one, because the research was conducted by a big food processing company. But as it turns out, even some scientists who are apparently not backed by the high fructose corn syrup industry think that the widely-demonized HFCS is not so bad.

One such voice belongs to John Sievenpiper, of St. Michael’s Hospital and the University of Toronto, who conducted a series of meta-analyses in which he examined dozens of human-based studies. The research team found “no harmful effects of typical fructose consumption on body weight, blood pressure or uric acid production.” Sievenpiper suggests that a person with a weight problem would do well to cut back on sugars, but to expect a magic-bullet effect across the board, in all populations, would be unrealistic because, “obesity is more complex than that.”

Jabr gives a helpful explanation of the difference between fructose, glucose, and sucrose, and what High Fructose Corn Syrup is all about. Whether a person eats table sugar or HFCS doesn’t matter much, because it all breaks down into glucose and fructose molecules. But when a person’s diet is top-heavy with fructose, the liver has to work too hard because it is practically the only place where the body can convert the stuff into energy. A stressed liver pushes back by overproducing uric acid, which can lead to high blood pressure, kidney stones, gout, and medical bills.

Sugar’s Bum Rap

Fructose especially has a terrible reputation, being blamed for insulin resistance, stuffed-up arteries, and fatty liver disease. Jabr learned that, like many other laboratory explorations of substances, some of the major fructose studies bear little relation to reality. (Incidentally, some serious doubts have arisen in recent years about the diabetes mice.)

First of all, the subjects are rodents, which although similar to humans in some ways, are unalike in important respects. For instance, when fructose goes into rat bodies, their livers turn half of it into fats, whereas a human body only does this with one percent of the fructose it receives. This is only one example of differences in the metabolic processes of the two species.

Another factor is that humans rarely consume fructose molecules unaccompanied by glucose molecules, because food just doesn’t grow that way. Even table sugar contains both elements, and HFCS does too, only more of the fructose. But the lab animals get pure fructose, which is enough to make an experiment invalid in some critics’ opinions. Also, rodent experimenters tend to slam the subjects with grotesquely exaggerated doses of the substance being assessed.

How it All Adds Up

Jabr allows that one deleterious effect of fructose in humans might require further scrutiny. It seems to lead to production of the hormone ghrelin, which makes people think they are hungry. Glucose, on the other hand, fosters the production of leptin, which makes people think they have been fed and are not currently hungry. To be in one or the other of those mind-states makes an enormous difference in eating habits. He seems to feel the appropriate response is to not worry about which kind of sugar is worse, but cut down on all of them. He says:

A small percentage of the world population may in fact consume so much fructose that they endanger their health… But the available evidence to date suggests that, for most people, typical amounts of dietary fructose are not toxic.

Exercising, favoring whole foods over processed ones and eating less overall sounds too obvious, too simplistic, but it is actually a far more nuanced approach to good health than vilifying a single molecule in our diet—an approach that fits the data.

Luc Tappy of the University of Lausanne sums up the argument in the phrase “entirely dispensable nutrient.” In other words, sugar is one nutrient we don’t need to worry about lacking. We get enough of it through ingesting a reasonably sane diet, and there is no need to sprinkle it on or stir it into anything. The adjective “dispensable” suggests a call to action: dispose of it.

Your responses and feedback are welcome!

Source: “Is Sugar Really Toxic? Sifting through the Evidence,” ScientificAmerican.com, 07/15/13
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  1. I agree with Jabr – reduce, and don’t fret. Obesity is complex, and certainly also is a result of sitting more, as well as sedentary lifestyles in general. I agree that everyone should check their sugar intake, and make sure sugars aren’t displacing other important nutrients or foods. But a balanced, and enjoyable, diet has some room for some sugar. I put a touch on my hot oatmeal so I can enjoy the whole grain. Sometimes I like jam on my toast. What’s important is choosing healthy foods first, getting enough activity, and enjoying sweet treats on occasion. When evaluating research, it is important to see if it is a rodent or human study, and if the eating or nutrition intake is “typical” (ie, not being delivered large glasses of fructose-liquid 3 times daily to induce an effect). I can share this info on behalf of my #client, the Calorie Control Council: http://www.fructose.org/Research%20Shows%20No%20Harm%20at%20Typical%20Intake%20Levels.html

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