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There’s good reason to believe sugar is making us sick, according to Gary Taubes: He says it’s the primary culprit behind soaring diabetes and obesity rates.

Is sugar bad for you? It depends on whom you ask.

According to the authors of a review published on Dec. 19 in the Annals of Internal Medicine, there is, "no clear link … between added sugar intake and health outcomes."

The authors, including researchers from McMaster University in Hamilton, the Hospital for Sick Children Research Institute in Toronto and the University of Toronto, reviewed nine guidelines from health authorities around the world, including the World Health Organization, and found they were not based on reliable science.

But before you take this as licence to binge on leftover eggnog and candy canes, consider the accompanying editorial published in the same journal. The editorial raises problems with the methodology and points out the review was funded by the North American branch of the International Life Sciences Institute, a group that represents pop and candy companies, including the Coca-Cola Co., Nestlé USA and PepsiCo Inc. (In their review, the authors also acknowledge they have a financial conflict of interest and warn "readers should consider our results carefully.")

The editorial goes on to suggest the review is an example of "the politicization of science," whereby inherent uncertainties of science are exaggerated "to cast doubt on the scientific consensus."

In fact, there's good reason to believe sugar is making us sick, according to award-winning U.S. journalist Gary Taubes. It's the primary culprit, he argues, behind soaring diabetes and obesity rates.

In his new book The Case Against Sugar, released just in time for post-holiday remorse, Taubes scrutinizes how the kind of research, exemplified by the review in Annals of Internal Medicine, has obfuscated what he suggests are dangerous effects of sugar.

He argues sugar likely causes a condition called insulin resistance, whereby the body fails to respond properly to insulin, a hormone that drives the body to store fat. Since the pancreas secretes insulin when one's blood-sugar level increases, Taubes suggests a high-sugar diet leads to this disorder by triggering the release of excessive insulin. When the body can't keep up with high levels of insulin, the result over time, he explains, is both Type-2 diabetes and obesity. While it's commonly believed that obesity leads to Type-2 diabetes, Taubes takes the view that a common dysfunction, insulin resistance, is the cause of both.

For more than 15 years, Taubes has challenged conventional thinking about salt, fat and calorie-consumption in his articles for prominent publications, including The New York Times, the journal Science, and his books such as Good Calories, Bad Calories and Why We Get Fat. His work has earned him multiple awards, including from the National Association of Science Writers in the United States, but also criticism for oversimplifying the complexities and ambiguities of nutrition.

The trouble with figuring out the health impact of sugar is it's difficult, if not impossible, to be definitive. When it comes to studying human nutrition, you can't keep human test subjects in a lab and feed them strictly controlled diets for years to see what happens.

When it comes to sugar, Taubes says, nutritionists, scientists and doctors have spent decades been mistakenly blaming dietary fat and salt for our modern illnesses, when they should have targeted sugar.

In a phone interview with The Globe, Taubes explained why you won't catch him eating leftover Christmas sweets.

The conventional wisdom is that obesity is caused by ingesting too many calories and expending too few. Why do you say this explanation is flawed?

Imagine we were talking about the problem of poverty, and I said the cause is that people make too little money and spend too much. Would I have told you anything meaningful or given you any understanding of the societal forces that cause people to be poor?

If someone's getting fatter, they have to be taking in more energy than they expend. And somehow we've taken that reality and transformed it into this idea of causation. I believed this explanation when I started this research 15 years ago, and now I'm stunned that anyone could believe that obesity is an energy-balance disorder, as opposed to the phrase researchers used in the 1930s, which is an endocrine disruption or hormonal abnormality.

The question is why do fat cells accumulate too much fat? And that's completely determined by hormones and enzymes and the central nervous system. We have this physics explanation for obesity based on energy, when it's clearly biological.

You mention that some researchers have long suspected sugar was the culprit. How did saturated fats get the blame?

In the 1960s when the nutrition and cardiology communities implicated saturated fat as the cause of heart disease through its effect on cholesterol levels, they were stuck with this reality that heart disease and obesity tend to go hand in hand. So they decided that since dietary fat has such dense calories – they have nine calories per gram compared with four for carbohydrates – the reason we get fat is because eating these dense calories kind of fools us into overeating.

How do the traditional diets of other cultures suggest this doesn't hold up?

The Inuit ate a lot of fat, though it wasn't necessarily saturated. The Massai, these pastoral populations in Africa, they ate a lot of saturated fat in milk from the cows they herded. There are South Pacific populations that have a lot of high-fat diets from coconut fats. All of these populations had relatively low rates of obesity, diabetes and heart disease until they started eating Western diets. So the question becomes, what aspect of the Western diet triggers these diseases? If you blame it on saturated fat, you have to ask why didn't these populations have high levels of heart disease before?

You have these epidemics of obesity and diabetes worldwide in vastly different human populations. And every population that transitions to Western diets eventually sees these epidemics. So the question is, can you find one or two items in the diet or lifestyle that are consistent throughout all these populations? And the answer is yeah. They add sugar and white flour. You can't refute the hypothesis that sugar is involved.

What role did the sugar industry play on public health recommendations around diet?

It took advantage very much of bad science. I think the initial problem is that the research community failed in their job, implicating fat when they should have been going after sugar, and implicating all calories were equal with this naive energy-balance conception. But given that, the sugar industry had a vested interested, as all industries do, in profit.

So beginning in the 1920s, they created organizations that were dedicated to convincing Americans that sugar was as healthy as possible and defeating any suggestions that it wasn't. By the 1960s, when our nutritionists and cardiologists began implicating dietary fat as the primary evil in the diet, and other British researchers began saying, "no, it's sugar; it's not fat," the sugar industry responded by paying researchers to produce documents that insisted it was fat. can we link to this study? They equated ambiguous evidence that sugar was involved as no evidence that sugar was involved. And they had their pick of influential nutritionists they could pay to write these studies because virtually all influential nutritionists did believe the problem was fat and not sugar.

The sugar industry, through its public health campaign, pretty much delayed the progression of the science and its implications by about 30 years. So research we are doing today should have been done in the 1980s, and beliefs that are finally forming today were beliefs that were forming in the 1970s before the sugar industry carried out its public health coup.

We've often heard the recommendation, "Don't eat sugar because it's just empty calories." How would that advice have benefited the sugar industry?

So long as sugar was empty calories, the worst that could be said about it is that we eat too much of it. "It tastes too good. Don't blame us. We have a great product and people over-consume it." So the solution is you don't regulate sugar, you just tell people to consume it in moderation and because it's excess calories, you can just burn it off with exercise.

If researchers had demonstrated that there was something uniquely deleterious about sugar – that it caused this condition called insulin resistance – independent of the quantity, in effect, the caloric content of it, then you've got a compound that's as bad for us as tobacco and you would expect the government to get involved.

As you mention, thoughts on sugar are now changing and the American Heart Association this year introduced recommendations on limiting children's sugar intake (to no more than six teaspoons of added sugar a day). What has prompted this change in attitude?

The obesity epidemic began to wake people up. People like neuroendocrinologist Dr. Robert Lustig at the University of California, San Francisco, myself and other people started in very visible ways arguing that sugar is the obvious culprit. Another factor was we had spent roughly 30 years directly and indirectly testing this idea that dietary fat was the problem, and we failed to confirm it. So more people are willing to look elsewhere.

In the book, you mention that sugar consumption actually increased during the Depression; people don't seem to stop buying it when they can ill-afford it. What are your thoughts about the efficacy of sugar taxes?

One of the questions is: if it costs you 20 cents more to buy a 20-ounce Coke, are you not going to buy it? The economists say it's effective. I wonder if the main benefit of sugar taxes is getting people to hear all the time that sugar isn't good for them. In that sense, you sort of change the default thought environment about sugar. In that sense, I think sugar taxes play a valuable role.

How do you approach sugar consumption in your household?

I tend not to eat it. But you can't keep your kids away from sugar in this environment. In an ideal environment, you could. So my kids get less sugar than probably their peer group, but they still get some. Of course, when I'm not around, they get more. But I'm one of these people who find it easier to avoid it entirely than to use it in moderation.

Given that sugar is in everything from salad dressing to cereal, how do you avoid it?

The obvious way is to stay away from things like sugary beverages, candies, cakes, all of life's pleasures, in effect. You can do it by reading nutrition labels; I tell my wife if it's over seven grams of sugar per serving, it's excessively sweet. You can find low-sugar versions of most foods. But what's stunning to me are health foods that, when you look closely, have more sugar than Coca-Cola or Pepsi. It takes conscious thought and you avoid a lot of processed foods.

But what's it like to abstain from, as you say, "candies, cakes, all of life's pleasures"?

This is where it gets complicated. My experience was informed by having been a smoker. While I was smoking cigarettes, I could not imagine life without them. And then you quit, and for about three weeks, you're miserable. For a year, you're unhappy. And eventually, you get to the point where you can't imagine why you ever smoked.

I think the situation is very similar with sweets. I don't consume sugar and I don't miss it.

But a low-fat diet without sugar is a diet that may not be very satisfying to many people. It's hard to find the pleasure in it. So if you don't eat sugar and you don't eat highly refined grains, the easiest way to make a diet very pleasing is to have it be high in fat, and to some extent, salt. Basically, you eat how the French would have eaten in the Julia Child era, without the pastry.

Now the question is, is this kind of diet going to kill you? The French were among the longest-lived populations in the world and they had anomalously low rates of heart disease. Hence, the French paradox. But I don't think it's a paradox; they were historically low sugar consumers.

What's wrong with the idea of eating sugar in moderation?

Well, define moderation. If you're obese and/or diabetic or predisposed to be, what does sugar in moderation mean? It's true if you ate five Snickers bar and drank four Cokes a day, and now you're eating one Snickers bar and drinking one Coca-Cola, that's more moderate consumption and I would think you would be healthier.

But there's this issue that maybe if you consume none at all, as well as making other changes to your diet, you might not be obese and/or diabetic. And it may be easier to consume none, like it is an ex-smoker to have no cigarettes than one.

Ultimately, it's a tradeoff. We all want to have pleasure in our lives. But I think we have to make that tradeoff with the awareness of what the costs are of what we're doing. And the costs may be much higher than we think.

The other argument is fine, eat sugar in moderation. But considering what the downside might be, why don't you go three months without it and see how you feel, and see how much you miss it?

This interview has been condensed and edited.