The Case Against Sugar

The diet that many public-health authorities believe is the healthiest is known as DASH—Dietary Approaches to Stop Hypertension. The authors of the first study on DASH described it as “rich in fruits, vegetables, and low-fat dairy foods and with reduced saturated fat and total fat.” A primary goal of this dietary prescription is to provide significant potassium, magnesium, and calcium, with the assumption that this in turn will lower blood pressure. But it also prohibits sugar, sweets, and sugary beverages other than fruit juices. Its benefits may come as much from that restriction as any other

Ultimately and obviously, the question of how much is too much becomes a personal decision, just as we all decide as adults what level of alcohol, caffeine, or cigarettes we’ll ingest. I’ve argued here that enough evidence exists for us to consider sugar very likely to be a toxic substance, and to make an informed decision about how best to balance the likely risks with the benefits

If it takes twenty years of either smoking cigarettes or consuming sugar for the consequences to appear, how can we know whether we’ve smoked or consumed too much before it’s too late?

And if the symptom or complication of metabolic syndrome and insulin resistance that manifests first is something other than getting fatter—cancer, for instance—we’re truly out of luck

if it takes years or decades, or even generations, for us to get to the point where we manifest symptoms of metabolic syndrome, it’s quite possible that even these apparently moderate amounts of sugar will turn out to be too much to reverse the situation and return us to health

This leads those like Cantley and Thompson directly back to sugar. As Cantley has said, sugar “scares” him, for precisely this reason. If the sugars we consume—sucrose and HFCS specifically—cause insulin resistance, then they are prime suspects for causing cancer as well, or at the very least promoting its growth. Even

But the other way to initiate the cancer process, according to these researchers, is to increase the levels of insulin and blood sugar in the circulation itself. Insulin resistance would do that. Thus

By metabolizing glucose at such a rapid rate, as Thompson suggests, these cancer cells generate relatively enormous amounts of compounds known technically as “reactive oxygen species” and less technically as “free radicals,” and these, in turn, have the ability to mutate the DNA in the cell nucleus. The more glucose a cell metabolizes and the faster it does so, the more free radicals are generated to damage DNA, explains Thompson. And the more DNA damage, the more mutations are generated, and the more likely it is that one of those mutations will bestow on the cells the ability to proliferate without being held in check by the cellular processes that work to prevent this pathological process in healthy cells. The result is a feed-forward acceleration of tumor growth.

Howard Temin, who would later win the Nobel Prize—demonstrating that cancer cells require insulin to propagate; at least they do so outside the human body, growing as cell cultures in the laboratory. This

Cancer researchers trying to make sense of this association would later say that something about cancer seems to thrive on the metabolic environment of the obese and the diabetic.
One conspicuous clue as to what that something might be was that the same association was seen with people who weren’t obese and diabetic (or at least not yet) but suffered only from metabolic syndrome and thus were insulin-resistant. The higher their levels of circulating insulin, and that of a related hormone known as insulin-like growth factor, the greater the likelihood that they would get cancer.