Dr. Robert Lustig is waging a war on sugar. He calls sugar the culprit behind obesity, and wants the government to regulate sugar the way it does alcohol. But his ideas have stirred up controversy among his medical colleagues who say he has insufficient evidence linking sugar to obesity. Dr. Lustig joins us to talk about his new book, “Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease.”

Interview Highlights

On the Prevalence of Sugar

"This is not just about high fructose corn syrup. The reason high fructose corn syrup is a problem is because it's cheap. And because it's cheap, it lowered prices on sugar, the entire world wide and that let it start being put into everything.

It started being put into hamburger buns, it started being put into hamburger meat. It started, you know, the barbecue sauce, the salad dressings, bottom line is, you can't find a processed food that doesn't have sugar. Eighty percent of all of the items in the American grocery store are now laced with added sugar, and that is very specifically because the food industry wants it to."

On How the Food Industry Has Changed the Food Supply

"Once fat was taken out of the diet, it was taken out for very [spurious] reasons, the food industry said 'Well, how are we going to make this stuff palatable? How's anyone going to eat it?' And so what they did was they substituted sugar for fat.

The perfect example is the chocolate milk that kids are drinking in the school today. I mean, which was worse, the fat or the sugar? I'll tell you — categorically, no ifs and or buts, the sugar is way worse.

The [ food industry removed] fiber from many foods. They did that for shelf-life, because you can't freeze fiber. Fiber makes food go bad on the shelf. So the things they have done to the food supply are very specifically for them. Adding sugar for palatability and sales, taking out the fiber for shelf life… that's what the book is about — to explain how our food supply has changed, even though we didn't ask for it to change."

On the Fatty Liver Disease Epidemic

"Only the liver can metabolize the sweet part of the molecule called fructose, which causes liver fat to build up. We now have an epidemic of non-alcoholic fatty liver disease that is actually bigger than the obesity epidemic because 33 percent of all adults in America currently have fatty liver: 45 percent of Latinos, 33 percent of Caucasians, 25 percent of African Americans.

Considering that this phenomenom, non-alcoholic fatty liver, hadn't even been diagnosed in anyone until 1980, the fact that one third of all America has it right now, that is actually the biggest epidemic. How did the liver fat get there? The answer – sugar."

On Defining Processed Food

"Processed food is fiberless food. That's basically what it comes down to. Processed food means that you've got to take the fiber out for shelf-life. And there are two kinds of fiber. There's soluble fiber: which is the kind of stuff that holds jelly together, and pectins, and things like that. And then there's the insoluble fiber: the stringy stuff, like, you know, cellulose, like what you see in celery. You need both. What I describe in the book is like it's kind of like your hair-catcher in your bathtub drain. Um, you have this plastic lattice work with holes in it. So, if you take a shower and the hair is coming down, it blocks up the holes, but only if the hair catcher is there. So, imagine that the cellulose is the hair-catcher, and imagine the hair is the soluble fiber, blocking up the little holes. When they're both there, it forms a barrier on the inside of your intestine.

You actually can see it during electron microscopy, that it's a secondary barrier that reduces the rate of absorption of nutrients from the gut, into the bloodstream. And what that does is that it actually keeps the liver safe, because it reduces the rate at which the liver has to metabolize, the stuff. And if you overload the liver, what it does is it has no choice but to turn extra energy into liver fat. And that's what drives this whole process. Is the process of liver fat accumulation, and the thing that does that the worst is sugar, especially when it's not teamed up with fiber."

On the Science Behind Some of His Claims

What we have on cancer and dementia right now is correlation. We do not have causation in humans, and I'm very clear on that, it's why I say it's not for sure. We have causation in animals. We know that these things cause cancer and promote cancer growth in animals. That's an across the board. You can ask Lew Cantley, from Beth Israel, who is now in Mount Sinai, about that. He was the one who did the 60 Minutes piece with us back in April. So, we have the data in animals, no ifs, ands, or buts. And we have the correlative data in humans.

Now, causative data is tough to come by, as you can imagine. Those are hard studies to do. Now, I'm the first one to say that we do not have causative data, in part, because everybody's exposed. There's nobody, who's not exposed. So that means the baseline's pretty darn high. So it's very hard to see an effect, especially since we've only just realized that this is a problem. So, this is going to take a while to get that data. Here's my issue – Medicare will be broke by 2024 — you want to wait?"

Robert Lustig, author, professor of pediatrics in the Division of Endocrinology and director of the Weight Assessment for Teen and Child Health (WATCH) at UCSF Medical Center

  • crayon

    I’ve been overweight since childhood, and nothing worked until I read Gary Taubes’ books and cut my carbs. I’ve lost 74 pounds, with about 15 left to go. My question is: for people who appear to be thin, or appear to be fit, how bad is sugar for them? Is it just that their metabolism can handle it, or is it still damaging?

  • doublegin

    Can you ask Dr. Lustig about the health benefits of green smoothies? In his book he says that fruit smoothies are similar to juice because the insoluble fiber is destroyed, but I’m wondering if the same is true of greens like collards and kale. I have been making green smoothies in my Vitamix for about six years and have found my digestion to be much improved in that time

    • I am a daily green smoothie person also. His primary concern is that glucose is more quickly absorbed without remaining locked in the fiber. Since green leafy veggies are low in glucose to begin with I’m not planning to stop using my vitamix. Way too many benefits and I just plain like them. (I’m not the fruit smoothie type.) When eating glucose rich foods I make sure they are still locked in their fiber. His book is excellent BTW.

  • Rajiv Narayan

    Some suggest the low-fat craze from the late 1980s to the mid 2000s is responsible for spawning the dramatic increase in the use of high-carb sugars, such as high-fructose corn syrup in processed foods. This timeline mirrors the epidemic rise in obesity. Does Dr. Lustig fear that targeting a currently over-used ingredient may spawn the overuse of a different processed ingredient that we’ll be reeling from in 30 years? How can we mitigate the blowback from food manufacturers?

  • kim shepard

    What about organic sugar? I am a sugar addict, probably my one true addiction, and so our my kids. However, we are all pretty fit, and hopefully I won’t jinx us, but hardly ever get sick when everyone else around us is, even those sugar haters who say how it breaks down the immune system. I have been an almost all organic everything shopper for years, and wonder if the organic sugar is some how different.

    • alekskela

      Organic, non-organic should not matter. Sugar is sugar.

      • kim shepard

        Well then my question would be is sugar the real villain? or is it the other ingredients that usually accompany sugar that has caused the rise in all these health issues. Because I am a 44 year old woman, who eats a lot of sweets, but I usually make them myself,or buy organic processed foods, that use a lot of sugar yes, but don’t have all that other stuff in it. And when getting life insurance I had to get a physical, and I found out I am in the top 1% of health, my insurance broker even congratulated me on my test results. So yes, I am the one annoying person who gets annoyed at the sugar haters. Is it really sugar, or the combination of sugar with all that fake stuff, food is made with these days, that has caused all these health problems? My kids eat sugar, probably a lot of sugar in the opinion of most people, and they are by far some of the healthiest kids at their school. I am in the opinion that it’s because when they were little and we lived in the country, they would be half way through their sandwiches before I noticed they should have washed their hands. But that’s a whole other show.

  • Lenny Lesser

    I agree that sugar is bad for 95% of people. What about endurance athletes? For those who exercise 8-12 hours of week and need a constant influx of calories, is sugar ok? The the high intensity exercise counter the harmful effects?

  • trite

    Overachiever? Oh dear, Michael Krasny. Please resist the impulse to boast.

  • Cal M

    Michael, the Doctor just stated that sweeteners such as honey and agave are “identical” to sugar in terms of their effects on the body. My understanding is that agave has a FAR LOWER glycemic index than sugar (this is a good thing). What’s the discrepancy? Is agave better or not?

    • disqus_MyR0Nmhzx8

      unfortunately agave does have the same effect…

    • dactylopterus

      Pure fructose also has a low glycemic index, because glycemic index is a measure of a food’s effect on blood glucose. Agave syrup is mostly fructose, which is the sugar that Dr. Lustig is most concerned about.

  • Belle Adler

    Why are told that a glass of wine is good for you when it’s sugar-loaded?

    • disqus_MyR0Nmhzx8

      everything in moderation!

  • Aaron

    Throughout our history, humans have never had to fear food that tasted sweet precisely because it wasn’t poisonous. Utilizing government laws to regulate sugar may be the easy part – the hard part will be to alter our Darwinian human instincts of survival.

  • Marga Castaldini

    I am using Xylo-Sweet. Is that o.k.?

  • Christopher Burnett

    Sounds very scary. Processed foods can easily be linked to chronic medical conditions, but what does the good doctor suggest? Any recommendations to bettering our diets? Thanks. – Chris

  • julian nichol

    What about breast milk being very sweet?

    • dp300

      Breast milk contains (same as cow milk) primarily lactose as its sugar. It is less concentrated and the fat changes over time and the casein to non casein protein ratio is lower. If you wanted to approximate Human milk from cow milk you would have to use 1%-2% milk and dilute it 1- 2.5 fold then add whey…then maternal antibodies and other unknown protecting agents and a large dollop of love and you still wouldn’t get there. For infants there is nothing wrong with even the sweetest of Human breast milk

  • disqus_MyR0Nmhzx8

    Please ask Dr. Lustig about cell inflammation due to high sugar and flour intake and all the diseases that accompany an empty carb diet.

  • Carrie Anne Arreola

    Thank you for this topic. Could you talk about how a vgan diet helps? Im thinking of going vegan.

  • Dan Foust

    Is it true that raw foods decrease calories because they are less digestible and consume more energy to digest?

  • chrisnfolsom

    We are taught to chew our food, and I know that mastication is in no way as good as a blender, but can we chew food too much? This is interesting. Obviously how and what we eat has changed and it’s affects along with a more sedentary lifestyle are showing their effects.

  • Rohit Priyadarshi

    The best food is what we evolved with, before we started cooking it to death. In absence of canine teeth, we were very likely fruits and vegetable eaters and ate it without processing like we do today. I am expecting that our bodies have evolved with that instead of all the stuff we eat today. I am very impressed with Dr. Robert Lustig’s discussion.

  • I think our lack of nutrition in food goes hand in hand with sugar. I think demonizing sugar ignores the problem that we dont know basic health in the US.
    I also disagree with your assessment on Juicing. Ive seen first hand the benefits of juicing. raw uncut vegetables can be harder to digest.
    Unbounded sugars are far worse then the once found in an orange.

    • adam222green

      “[…] are far worse then the once found in an orange.”

      That’s a marvelously accented use of the words then and once.

      I think your point is to say that health is a matter of education.

  • Susan

    If the aim is to stabilize insulin, what is the most effective way to eat in order to do that?

    Also – I heard you interviewed by Alec Baldwin and you
    openly stated you don’t practice what you preach, you eat a bagel and cream cheese for breakfast and processed food for lunch because you’re busy seeing patients. How about a few celery sticks with 2 tablespoons of natural (no sugar or palm oil added) crunchy peanut or almond butter for lunch with a boiled egg or two?

  • Lucinda

    I’ve always believed that whole grains are fiber. Paleo diet says grains are bad and cause leaky gut syndrome. Your “fiber mesh” sounds like the opposite of leaky gut but you say it is created by fiber (whole grains)? Who is correct?

  • Denise

    Correction for Michael, the last caller said it was the advice of the local health food store that caused her to get her glucose normal, not the doctor. Doctors do not know anything about nutrition and this is another problem for people who need better information about what to do.

  • I, like many informed parents, am making every effort to get my child’s health and nutrition off to a good start. My son is now 11 months. I make just about all of his solid food and he is still breastfeeding. I just heard on the program that blending fruits and vegetables (pureeing in my case) “destroys” just about all of the insoluble fiber. Do babies just have a lower fiber requirement or is my son missing out on fiber whenever I blend his food?

  • fritzlan

    Sadly, not much is going to change. The food industry gives politicians lots of money to fund their endless campaigns. Congress then gives billions right back the food industry for this favor. Check it out, look up your local Congressperson and see how much cash they received from the sugar and food industry.

    And we enable it.

  • If you have fair skin and blue eyes, odds are that your ancestors lived for hundreds of decades in places that were too cloudy and too cold to grow sugar cane, corn and other sweet stuff. Our metabolic ancestry simply does not have the ability to contend with it successfully.

  • Tony Hanson

    The only counter-argument Lustig gave against the libertarian concern of government intruding more and more into our lives and bodies with his proposal for more regulation, was that industry, without our choice puts sugar into food. Therefore, it’s a good idea to regulate it. Of course, that is a very flawed argument. Industry sells lots of products that are not good for you. It does not follow that you are forced to buy them. There are plenty of alternatives. Why do liberals persist in their totalitarian tendencies to control every aspect of our lives? Keep the government out of my stomach!

  • DavidMDriscoll

    Is Dr Lustig really suggesting that there isn’t evidence to support views contrary to him (or was the suggestion that the evidence was tainted)?

    He was certainly called out for overstating the evidence and poorly extrapolating rat research at a conference he spoke at earlier in the year – check out the Q and A video in the attached article by David Despain (as well as the other lectures)! for a full review and links to all lectures – if not just watch the Q and A at and

    The major issue with Dr Lustig’s theory is looking at US Sugar intake over history – levels were still high in the early 20th century – so saying it is sugar is either an oversimplification or there is a threshold value that we have recently crossed. Methinks that it is a perfect storm of more sugar and less burning it up with physical activity!

    Plenty of evidence flew back and forth in this exchange with Dr Lustig too!

  • DavidMDriscoll

    When I do an honest literature review in pubmed, these are the review article re fructose I find
    Metabolic Effects of Fructose and the Worldwide Increase in Obesity

    Health implications of fructose consumption: A review of recent data

    Effect of fructose on body weight in controlled feeding trials: a systematic review and meta-analysis

    The Effects of Fructose Intake on Serum Uric Acid Vary among Controlled Dietary Trials

    Effect of fructose on blood pressure: a systematic review and meta-analysis of controlled feeding trials

    Role of fructose-containing sugars in the epidemics of obesity and metabolic syndrome

    Evidence-based review on the effect of normal dietary consumption of fructose on blood lipids and body weight of overweight and obese individuals

    Fructose toxicity: is the science ready for public health actions

    Review article: fructose in non-alcoholic fatty liver disease

    ‘Catalytic’ doses of fructose may benefit glycaemic control without harming cardiometabolic risk factors: a small meta-analysis of randomised controlled feeding trials

    Effect of fructose on glycemic control in diabetes: a systematic review and meta-analysis of controlled feeding trials.

  • Curious if anyone here or the Dr. Himself has heard of CSID, a genetic enzyme deficiency that minimizes effective digestion of sucrose and starch. The dilemma in light of the topic is that fructose s is the main source of digestible carb and most fiber-rich foods contain too much starch (all grains) for us to digest properly. We use agave and honey to gain essential carbs in our very limited diet. See my personal blog for more at

  • Elliott Eugene Blake

    What else is new? Junk food ruins your health. I personally think it would be great for the government to enact vast regulation regarding food and nutrition. Arguing that it’s a civil liberty to eat garbage and die a slow and expensive death is like saying that it’s your right to drive your car into a telephone pole. Sure you can do it, but we all have to pay for it; and at that point your rights are limited.

  • Julie

    Gary Taubes will be speaking at the JCC East Bay this Thursday, February 7 at 7:30 PM. Buy tickets online:

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