In April, the New York Times Magazine published a powerful, misleadingly-titled article called Is Sugar Toxic?. I have since heard several interviews with the article’s author, Gary Taubes, and watched a lecture by one of the key scientists that Taubes highlights in his article, Robert Lustig. I find their argument pretty compelling (their real argument, not the simplified article title’s “argument”). I was going to write a summary of their argument (which, if true, could be very important to healthy living), but the more I’ve tried to bone up on the topic, the more complicated it’s gotten. It’s even worse as this topic covers all manner of physiology, biochemistry, and several other subjects I only have basic understandings of. So my opinion on this subject shouldn’t really sway anybody very much.
Anyhow, the Argument as I understand it.
Taubes isn’t really saying that sugar itself is toxic (Lustig is, but in the same way that the alcohol is technically toxic). But putting it into common language, they are saying that sugar and corn syrup (also known as sucrose and fructose), when eaten in large enough quantities (a threshhold that most Americans meet, cross and double) causes the body to react in incredibly unhealthy ways that cause obesity, diabetes, heart disease, and possibly even cancer. Eating lots of calories causes many health problems as well, but they argue that digesting sucrose and fructose create special problems above and beyond the disorders caused by overeating. So I guess you could revamp that article title to “Are Certain Types of Sugar So Harmful to Humans That They May as Well Be Toxic?”
Lustig’s lecture makes it very clear: the body digests different substances in many different ways. They get processed by different organs, using different enzymes, creating different byproducts, which in turn effect other biological processes not related to just digesting your candy bar. In his lecture, Lustig shows that the digestion of normal carbohydrates (bread, vegetables, etc.) gets energy to your cells, stores some of that energy in the liver, contributes slightly to weight gain, and not much else. He then shows how the process of digesting fructose and sucrose is more similar to those of digesting alcohol and pure fat. The process likewise gets energy to your cells, but perhaps half of these sugars are then stored as fat. These digestive processes then also create chemical byproducts which make you stay hungry longer, increase blood pressure, increase chances of diabetes, and contribute much more to the creation of fat. Taubes adds on to this, claiming that it also increases the body’s secretion of hormones that can help cancers to grow.
Lustig is on a crusade about this. That’s why he keeps referring to sugar as poison. We know that a high-fat diet is unhealthy, and Lustig argues persuasively that, in effect, a high-sugar diet is a high-fat diet because of how the body metabolises sugar. It also follows from this that all calories are not created equal, at least as far as obesity, heart disease, and diabetes are concerned. Eating 500 calories of candy and 500 calories of spaghetti effect your body differently. In a way, this is common sense; eating 10 carrots is better for you than drinking a can of soda. But the majority of public nutrition info in the past few decades has focused on calories in general, exercise, and fat consumption. If sugar (which is added to almost any food you can buy) is as big a factor as any of those other three, then that’s big news.
It would be one thing if this was an issue of individual diet and individual choices, but multiply the surprising impact of sugar times the number of Americans who eat food, and the number of residents of other nations who have largely adopted the American way of eating. Taubes mentions that some medical researchers see diabetes and obesity together in so many patients that they have coined a new term: “diabesity”. Lustig says that the United States has an epidemic of obese six-month olds. Some studies show that 17% of all American health care spending is on obesity-related treatments. This is horrifying.
Anyhow, biology was never my strongest subject, but I would recommend listening to those Taubes interviews if you’re interested, and reading his NYT Mag article. And then, if you want the hard stuff, or if biochemistry equations make you warm and tingly inside, watch the Lustig lecture. I could be wrong, they could be wrong/lying, I just don’t know. Worth a look, though.