Why You Should Never Drink Fruit Juice, with Dr. Robert Lustig
Fruit juice has long been considered a healthier alternative to soft drinks like Pepsi and Sprite, but unfortunately this is far from accurate. In this episode of The Brain Warrior’s Way Podcast, Dr. Daniel Amen is again joined by “Fat Chance” author Robert Lustig for a discussion on why fruit is good for your body while fruit juice is not, and why we need to shift our focus to protecting the liver and feeding the gut.
Dr. Daniel Amen: Welcome to the brain Warrior's way podcast. I'm Dr. Daniel Amen.
Tana Amen: I'm Tana Amen. In our podcast, we provide you with the tools you need to become a warrior for the health of your brain and body.
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Dr. Daniel Amen: Welcome back. I'm here with Dr. Robert Lustig. You had talked about two Netflix documentaries that people could watch, Fed Up and Sugarcoat.
Dr. Robert Lustig: Sugarcoated.
Dr. Daniel Amen: You're All Sugarcoated. You're also the author of Fat Chance, the Fat Chance Cookbook, the new book, The Hacking of the American Mind. I hope you're finding this as fascinating as I am. What's the deal with virtues? I mean, everybody thinks, "Oh, if I can get my kid to eat fruit, to drink fruit juice in the morning, I'm a good mom or I'm a good dad." My dad's a grower of oranges. It's just been thought of is a health food for so long. then when I watched Sugar, the Bitter Truth, I don't think I've had a glass of juice since then.
Dr. Robert Lustig: Good, as you should. Let me try to explain a relatively complex subject. The short answer is fruit is good, juice is bad. Now you would say, "They're the same." And most people think of them as the same. Certainly the USDA thinks of them the same. They consider fruit juice fruit, as simple as that.
I would argue that they are not the same at all. The difference between the two is the fiber. Fruit has fiber. Fruit juice has lost one of its fibers. There are two. Whole fruit and for that matter, anything that comes out of the ground, any carbohydrate that comes out of the ground ...
Dr. Daniel Amen: Potatoes.
Dr. Robert Lustig: Potatoes, wheat, eggplant, anything comes with numerous nutrients, but two forms of fiber. There's soluble fiber, like for instance, pectins like what holds jelly together, inulin, which is a very specific plant, sugar source storage unit. These are globular. They are soluble in water. It's what metamucil is, psyllium. If you add water to Metamucil, you get this gel like stuff. That's soluble fiber.
Dr. Daniel Amen: Which you ingest.
Dr. Robert Lustig: Right, so when you consume fruit, you're getting the soluble fiber. When you consume fruit juice, you're getting the soluble fiber. But then there's this second fiber, insoluble fiber, so like cellulose, like the stringy stuff in celery, chitlins, many others, fructans that are stringy. They're long. They form a lattice work on the inside of the intestine. When you consume fruit, you're getting both of them. You're getting them with the appropriate geometry. The geometry matters. I'll explain how that works in a minute.
When you make fruit juice, you're throwing the insoluble fiber in the garbage. You're only getting the soluble fiber. You're only getting one of the two. When you smoothie a fruit, so put it in a Vitamix or a Breville or whatever, you are shearing the insoluble fiber to smithereens. You're cutting it up into little chunks that are so big that it will not do the function that you need it to do, which I'm going to explain in a minute.
You need the two together. Here's how this works. Imagine that you have a spaghetti colander, okay? Metal thing with holes, right? You run water through it. Water goes straight through, of course. Now take a blob of petroleum jelly, throw it into the center of the colander. Now run the water. Still runs through. Might bounce off the petroleum jelly, but basically you're going to end up with a wet sink. Now take your finger and rub that petroleum jelly all along the inside of that colander. Now run the water. Now you have an impenetrable barrier. The water won't go through, because the petroleum jelly is basically plugged the holes in the colander.
Well, that's what's happening in your duodenum, in the first part of your intestine. The insoluble fiber, the cellulose, the stringy stuff, acts like a fishnet. The soluble fiber acts like the kelp that plugs the holes. Together the two, when you have the appropriate geometry, acts as an impenetrable barrier on the inside of your intestine. Thus reducing the rate of absorption of carbohydrate and the various molecules, sugar, et cetera, from getting into the portal vein so that it doesn't all go to the liver. The whole goal of this is to keep the liver healthy by not flooding it. By cutting back on how fast the glucose and the fructose and the other nutrients reached the liver, you are protecting your liver. That is precept number one, protect the liver.
Now if you don't absorb it early because you've made this nice fiber gel, that means more of what you ate will go further down the intestine. What's down the intestine that wasn't in the front of the intestine. The bacteria, the microbiome. We now know the microbiome is huge in terms of metabolic health for all sorts of reasons, which we can go into if you like, but it's a big deal. You want your microbiome fed. The point is that if you didn't absorb it early, that means you're feeding your microbiome later. So even though you consumed it, even though it past your lips, you didn't get it. Your bacteria did. So even though you counted it as calories because it passed your lips, it doesn't count as calories because the bacteria chewed it up, not you, and you fed your gut.
Those are the two precepts to determine whether something is healthy, protect the liver, feed the gut. If a food does both, and fruit does both, it's healthy. If a food does neither, that would be like a soda, it's not healthy because you're flooding your liver and starving your gut. If a food does one or the other, but not both, like for instance, fruit juice, then it's halfway. That's what the data show. The empiric data on fruit juice and diabetes or fruit juice and heart disease or fruit juice and mortality show not as bad as soda, but clearly not as good as any other non-caloric beverage. Fruit juice is not good, just not as bad as soda.
Dr. Daniel Amen: That's so important. I mean, what an important message. Then when you read the labels, fruit crystals and organic grape juice is, it's just everywhere that fructose, and you had said it earlier, it's because that's the sweet part of the sucrose molecule ...
Dr. Robert Lustig: Exactly.
Dr. Daniel Amen: ... is fructose.
Dr. Robert Lustig: Exactly.
Dr. Daniel Amen: Is there a difference between high fructose corn syrup and regular corn syrup?
Dr. Robert Lustig: Well, yes, there's a difference between high fructose corn syrup and regular corn syrup. The question is, is there a difference between high fructose corn syrup and sucrose or table sugar and the answer's no. High fructose corn syrup is cheaper. It's homegrown. Iowa's filled with corn, got to do something with it. 17% of the corn crop each year is turned into high fructose corn syrup for sweetening this, that and the other thing. It is so cheap that it found its way into virtually every other food stuff that we buy at the store. Whoever heard of salad dressing having sugar, but go check your commercial salad dressing. The only way you get salad dressing without sugar is if you make it yourself. It's just that simple.
Dr. Daniel Amen: Or McDonald's grilled chicken has sugar.
Dr. Robert Lustig: Absolutely.
Dr. Daniel Amen: I'm like, "Why does it have sugar in it?"
Dr. Robert Lustig: There are only seven items at McDonald's that don't have sugar. Ready? French fries, but actually I've heard that back in the day they actually did add sugar because it browned the French fries better, but I think that they've stopped doing that now. Number two, the sausage does not have sugar in it. I was surprised. Chicken McNuggets do not have added sugar, but the dipping sauces do, so that's not a good one either. Hash Browns, for the same reason, the French fries, they don't have sugar. After that it's ice tea, if you say no sugar. Coffee, if you don't want sugar and water. That's it. Okay? Everything else at McDonald's is loaded with added sugar on purpose for their reasons not for yours. They know when they add it, you buy more.
Dr. Daniel Amen: Well, and I think of fast food basically is fiberless food.
Dr. Robert Lustig: That's right.
Dr. Daniel Amen: That way you can go in, you basically don't have to chew it. You just swallow it. Then you go out. So they get more turnover.
Dr. Robert Lustig: Absolutely.
Dr. Daniel Amen: People.
Dr. Robert Lustig: So I'm going to tell you ...
Dr. Daniel Amen: What's ...
Dr. Robert Lustig: ... a funny story. Let me just tell you a funny story about how important fiber is. I live in San Francisco. I have lived there twice. I lived there when I was a fellow back in the early '80s. Then I moved back in 2001, so two separate times. When I went to a Chinese restaurant in San Francisco the first time I was there, every restaurant had brown rice, because brown rice was good for you, right?
Then I left and I lived in New York and Madison, Wisconsin and Memphis. When I came back to San Francisco, no restaurant had brown rice, only white rice. Now, when I lived in New York, there are plenty Chinese restaurants there. They all had brown rice. When I came back to San Francisco, they've gotten rid of the brown rice. They only had white rice. Now why is that if it's healthy for you?
Dr. Daniel Amen: I have no idea.
Dr. Robert Lustig: Because in San Francisco, they charge for the rice. In New York the rice was free. The restaurateurs in San Francisco realized when people ordered brown rice, they only had half a bowl. But when they ordered white rice, they ate two bowls, because the fiber was satiating. Whereas in New York, they're perfectly happy for you to have brown rice because it was free.
Dr. Daniel Amen: Oh, that's so interesting.
Dr. Robert Lustig: Why would they want to give you two bowls?
Dr. Daniel Amen: It's funny. Along that line, have you ever asked yourself why when you go to a restaurant, do they give you free bread? The first thing they ask you is what alcohol beverage can I get you?
Dr. Robert Lustig: Right, absolutely.
Dr. Daniel Amen: Because both of them lower frontal lobe function. Bread causes an insulin spike, which drives serotonin, which drives tryptophan into the brain, so it actually makes you happy. It's the don't worry, be happy chemical. Even though you go in and go, "I'm not going to order dessert. I'm going to be good. I'm going to stay on my diet," that as soon as you get the bread, the diets out the window and alcohol drops your frontal lobe. They're very strategic on how to get more money out of your credit card.
Dr. Robert Lustig: There's no question about how strategic they are. They've got it down. The point is they know and you don't.
Dr. Daniel Amen: When we come back, we're going to talk about the hacking of the American mind and what's really going on in our society. You're going to find how similar it is to my new book, The End of Mental Illness and the Evil Ruler. You've heard me talk about if I was an evil ruler, how would I create mental illness in America? Dr Lustig is going to help us with that. Stay with us.
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