Op-Ed: How much sugar is too much?

Sugar may well be a killer. The conventional thinking is that it’s an “empty calorie” — it fills you up without providing nutrients. But there’s a growing body of research suggesting that sugar actually triggers a disorder known as metabolic syndrome, which the Centers for Disease Control and Prevention says now afflicts 75 million Americans. If it does, then it plays a critical role in virtually every major chronic disease, including obesity, diabetes, heart disease, cancer and even dementia. The catch is that the evidence is ambiguous. At this point, scientists can’t tell us definitively whether this accusation against sugar is true. Nor can they exonerate sugar.

Given the lack of clarity, and the stakes, how much sugar is too much? How little is still too much? The World Health Organization recommends that we get no more than 10% of our calories from sugars — sucrose and high-fructose corn syrup in particular — and that 5% would be even better. For someone who eats 2,000 calories a day, that’s less than a 12-ounce can of Coca-Cola. Other scientists are more flexible. They simply urge moderation.

The problem is, everyone’s a little different; one person’s “enough” is another’s “too much.” As individuals, we only know we’re consuming “too much” when we’re getting fatter or manifesting other symptoms of metabolic syndrome. Our blood pressure is going up, for instance, or our HDL cholesterol (i.e., the good cholesterol) is low. At that point, we may assume that we can dial it back a little and be fine — eat ice cream on weekends only, rather than as a daily treat.

If, however, it takes years or decades for us to get to the point where we manifest symptoms of metabolic syndrome, it’s quite possible that even apparently trivial amounts of sugar will turn out to be too much to reverse the situation and return us to health. And if the symptom or complication of metabolic syndrome that manifests first is something other than getting fatter — cancer, for instance — we’re out of luck.

The authorities who argue for moderation in our eating habits tend to define it, tautologically, as whatever works for them, or a relatively small number of research subjects. They assume that the same approach will have the same beneficial effect on all of us (and that it will continue to work for them as well).

If it doesn’t — if we fail to remain lean and healthy — they assume that we’ve failed in our assessment of moderation. By definition, we ate too much sugar. What we thought was moderation was, in fact, too much.

To better understand the folly of this tautological logic, imagine a situation in which a cigarette smoker who doesn’t get lung cancer (or heart disease or emphysema) assumes that those smokers who do are those who smoke “too much.” He’d certainly be right, but we still wouldn’t know what constitutes a healthy level of smoking, or whether such a thing as smoking in moderation even exists.

How often can we smoke cigarettes without doing at least some harm to our health? Doctors these days answer “never,” thus redefining the concept of moderation. We don’t say smoking too much causes lung cancer, although that’s surely true. We say smoking does.

The same hard line may also make sense for sugar. If it takes 20 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? Isn’t it more reasonable to decide early in life (or early in parenting) that not too much is as little as possible?

Any discussion of how little refined sugar is too much also has to account for the possibility that sugar is a drug and perhaps addictive. Even if “people just act like it is,” as the journalist-historian Charles C. Mann has written, this suggests the possibility that trying to consume sugar in moderation, however that is defined, may be no more successful for some of us than trying to smoke cigarettes in moderation — just a few cigarettes a day, rather than a pack. Whether or not we can avoid chronic disease by doing so, we may not be capable of managing our habits, or managing our habits might become the dominant theme in our lives (just as rationing sweets for our children can become a dominant theme in parenting).

Some of us certainly find it easier to consume no added or refined sugar than to consume a little — no dessert at all, rather than a spoonful before pushing the plate to the side. If sugar consumption is a slippery slope, if a little creates a fierce craving for more, then advocating moderation is not a meaningful concept.

I keep returning to a few observations from my research — unscientific as they may be — that make me question the validity of any definition of moderation in the context of sugar consumption. One was a comment made by the British physician Frederick Slare in 1715, when he wrote a pamphlet defending sugar as a healthy item. At a time when sugar consumption in England was perhaps 5 pounds per capita per year — equivalent to consuming only the sugar in a single can of Coke every six days — Slare still considered it enough to make women “inclining to be fat … to be fatter than they desire to be.” If a single Coke every six days makes you fatter than you desire to be, isn’t that already too much?

Ultimately and obviously, the question of how much sugar is too much is a personal decision, just as we all decide as adults what level of alcohol, caffeine or cigarettes we’ll ingest. We have to balance the likely risks with the benefits that would come from quitting. To know what those benefits are, though, it helps to know how life feels without sugar.

Former smokers often say that it was impossible for them to grasp what life would be like without cigarettes until they quit; that through weeks or months or even years, it was a constant struggle. Then, one day, they reached a point at which they couldn’t imagine smoking a cigarette and couldn’t imagine why they had ever smoked, let alone found it desirable. A similar experience is likely to be true of refined sugar — but until we experiment, we’ll never know.

Gary Taubes is the co-founder of the Nutrition Science Initiative and author most recently of “The Case Against Sugar.”

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