Robert Lustig is a medical expert at the University of California, San Francisco, who has written extensively about the major health problems attributed to sugar. He's written two major papers — "Fructose: it's 'alcohol without the buzz'" and "The toxic truth about sugar" — laying out the case for treating sugar like a controlled substance, similar to alcohol and tobacco. I spoke with Lustig on the phone in June 2014 about the issue. This interview has been edited for length and clarity.

German Lopez: Walk me through the argument for treating sugar like a controlled substance.

Robert Lustig: Once upon a time, sugar was a condiment. Now it's a diet staple. That's a problem, because as it turns out, we as human beings have a limited capacity to metabolize it. There are things you can do to up your metabolism, like vigorous exercise. But the bottom line is we have a limited capacity to metabolize it — virtually like every poison, kind of like alcohol. So a little is okay; a lot is not.

The dose determines the poison. The data says that the dose on average that is safe is six to nine teaspoons of added sugar per day. Currently, Americans are at 22 teaspoons of added sugar per day. That excess is driving obesity, diabetes, lipid problems, heart disease, cancer, dementia, fatty liver disease — virtually every chronic metabolic disease that you can think of is being driven by this excess of sugar.

"If a substance is abused and addictive, ... that's criteria for regulation"

This has all been put into our food by the food industry because they know when they add it, people buy more. It's addictive — weakly so, but addictive nonetheless.

Now, how do you deal with addiction? You get off it, right? But how do you get off it if it's all around you?

The definition of addicted is that you know it's bad for you and you can't stop anyway, like heroin, cocaine, alcohol, and nicotine. You know it's bad for you. You know it will kill you. But you can't stop anyway, because the biochemical drive to consume is greater than any cognitive ability to restrain oneself.

There are two phenomena attached to addiction: one's called tolerance, the other is withdrawal. It turns out sugar does both of those as well.

If a substance is abused and addictive and it contributes to societal problems, that's criteria for regulation.

GL: Is that really grounds for considering it a controlled substance, though?

RL: There are four things that have to be met in order to consider a substance worthy of regulation. Number one: ubiquity — you can't get rid of it, it's everywhere. Number two: toxicity — it has to hurt you. Number three: abuse. Number four: externalities, which means it has a negative impact on society.

Sugar meets all four criteria, hands down. One, it's ubiquitous — it's everywhere, and it's cheap. Two, as I mentioned, we have a dose threshold, and we are above it. Three, if it's addictive, it's abused. Four, how does your sugar consumption hurt me? Well, my employer has to pay $2,750 per employee for obesity management and medicine, whether I'm obese or not.

"in order to solve this public health debacle we have to reduce consumption"

We meet all four criteria for regulation. Now, obviously, no one is thinking about banning the stuff. Me neither. You don't think we're going to have ice-cream sodas speakeasies or anything like that. We tried banning alcohol, and look what happened; it was a complete and utter disaster.

So no one is talking about getting rid of it, but in order to solve this public health debacle we have to reduce consumption. The only way to do that for an addictive substance is to reduce availability, and the only way to reduce availability is taxation or restriction of access or banning. Forget banning; that's out. That leaves taxation and restriction of access — well, that's regulation.

GL: The thing that led me to look into your paper is that I wrote an article a couple weeks back about how the three most dangerous drugs in the country are legal: tobacco, alcohol, and prescription painkillers. And a few people mentioned that I forgot sugar. That idea really interested me.

RL: Yeah, that's right. The Wall Street Journal asked Americans what are the most dangerous of four substances in America: tobacco, 49 percent; alcohol, 24 percent; sugar, 15 percent; and then marijuana, 8 percent. Sugar was doubly worrisome to Americans than marijuana was. How about that?

GL: There are plenty of people out there who want to increase the alcohol tax to help fight health issues and crime, but they have a really hard time selling that to the public. With sugar, I imagine that would be an even bigger hurdle.

RL: No question. All true. The questions are what are you doing with the money and why are you suggesting the tax. That's what this issue is about.

Now, I will tell you that America doesn't trust its politicians. And we have a good reason for that: they suck. If you don't quote me, I will be upset. The reason they suck is because, number one, they're interested in power, not doing the right thing, and, number two, they take money. So everyone assumes that any tax that you would place on any given substance is either a money grab for coffers for other things or going into politicians' pockets. Based on previous behavior of our elected officials, that's a damn good guesstimate. We've seen this movie before.

"The questions are what are you doing with the money and why are you suggesting the tax"

So in order to make such a sugar tax palatable to the general populace, what you have to do is tie the tax to a benefit, and it has to go to back to the community that it came from.

Example: Mexico passed a soda tax in October. Mexico doesn't even have potable water. You're going to tax the only thing that's safe to drink? They did. How did they do that? Because they tied the tax to improving the water supply all over the country. So what they did was tie the carrot to the stick.

That's called differential subsidization. In order to change behavior, there's two forms: carrots and sticks. Neither work alone. But put carrots and sticks together, that's when they work. When you do that, you nudge people off their mark and get them to migrate to the behavior that you're trying to foster.

GL: So how would that concept work with sugar in the US?

RL: In America right now we subsidize all of the bad stuff: corn, soy, sugar — commodities of storable foods. We have since 1933, when we had the Dust Bowl. That's when we had a destitute population that was starving. So we needed to produce storable food that wouldn't go bad, that we could put in silos, and ship around to the rest of the country to keep everyone from going hungry. That's what we did, and it made perfect sense in 1933.

Do we need those policies today? No, we don't. But they've only gotten and more ingrained. That's because politicians like the idea. Americans don't care; Americans just like the idea of cheap food.

You could instead subsidize broccoli [with revenues from a sugar tax]. Instead, we subsidize all the bad things, and now we're over our limit.

GL: One potential hurdle is that controlled substances are typically seen as drugs. Do you consider sugar a drug?

RL: Of course it's a drug. It's very simple: a drug is a substance that has effects on the body, and the effects have to be exclusive of calories.

So in order to qualify it as a drug, the negative effects of sugar have to be exclusive of its calories. Is 100 calories of sugar different from, say, 100 calories in broccoli? The answer is absolutely.

"Sugar is the alcohol of a child"

Can you name another substance of abuse for which the effect of the substance is more dangerous than the calories it harbors? Alcohol. Its calories are dangerous not because they're calories; they're dangerous because they're part of alcohol. Sugar is the same.

Sugar is the alcohol of a child. You would never let a child drink a can of Budweiser, but you would never think twice about a can of Coke. Yet what it does to the liver, what it does to the arteries, what it does to the heart is all the same. And that's why we have adolescents with type 2 diabetes.

GL: Can you elaborate on that? Could you describe the precise negative biochemical effects sugar has on the body?

RL: There are three.

One, fructose, the sweet molecule in sugar, is not metabolized like glucose. It's metabolized in the mitochondria, and it is metabolized in the liver to liver fat. That liver fat mucks up the workings of the liver and leads to a process called insulin resistance. That raises your insulin levels because your pancreas has to make more insulin. That drives all the chronic metabolic diseases we know about, plus it burns out the pancreas, leading to diabetes.

"For other drugs of abuse, we limit them in various ways"

Two, cellular aging. When bananas ripen, they brown. The sugar in the bananas binds to proteins in the bananas nonenzymatically, even in dead tissue. That's called the cellular aging or Maillard reaction. That happens to everyone all the time, so we brown inside. You don't want to brown very fast, but we're all browning because that's how we age. But sugar makes us brown seven times faster; it basically kills our organs quicker.

Three, sugar is addictive. So a little makes you want more, because of the effect of the reward center of the brain.

For other drugs of abuse, we limit them in various ways. If they're legal drugs of abuse, we make them expensive and we have all sorts of restrictions on access. But for sugar we have nothing. We give it to newborns, we give it to two-year-olds, we have it at birthday parties and at school, etc. So we have a nation of childhood addicts; just walk into any supermarket and watch these kids nag their parents for the stuff. That's why we should regulate it.

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