Qualy #102 - Is the food industry still saying that all calories contribute equally to adiposity and insulin resistance?

**Peter Attia** (0:11)
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And currently the food industry says, I mean, I haven't really paid much attention to this, to be honest with you, in the last few years, but is the food industry basically still saying that while a can of Coke is not ever deemed even by Coca-Cola to be as nutritious as a carrot, in the end are they basically saying that all calories contribute equally to adiposity and insulin resistance?

**Robert Lustig** (1:02)
Yes, they are all saying it's about obesity and therefore it's about energy balance, therefore it's about calories, therefore all calories are the same. That's what they say. It is absolutely not true. And we have all the reasons in the world to show why it's not true. We have empiric data, we have mechanistic data, we have plausibility data, we have hard data that show that is just not the case. And if you want, I'll give you examples of it. All right, let's start.
Let's talk about fiber. You eat 160 calories in almonds.
How many do you absorb?

**Peter Attia** (1:37)
Two thirds.

**Robert Lustig** (1:38)
130
Yeah, I mean, 75%, okay. Well, what happened to the other 30?

**Peter Attia** (1:43)
Presumably it's going to drag some stuff out in your colon.

**Robert Lustig** (1:47)
Well, no, what happens is the soluble and insoluble fiber in the almonds forms a gel on the inside of the intestine. You can actually see it on electro microscopy, a whitish gel.
That's gonna act as a secondary barrier preventing absorption of some of those almond calories early on. Well, if they don't get absorbed in the duodenum, where do they go next?

**Peter Attia** (2:08)
Ilium, jejunum.

**Robert Lustig** (2:08)
Jejunum.
Well, what's in the jejunum that's not in the duodenum? The microbiome.

**Peter Attia** (2:13)
Yeah.

**Robert Lustig** (2:13)
The duodenum is essentially sterile. It's got a pH of one.
Only H pylori can live there. You have to get the bicarbonate infusion.

**Peter Attia** (2:21)
Wait, you're saying that that lining is formed in the duodenum?

**Robert Lustig** (2:25)
Duodenum, yeah.
Exactly. To prevent your liver from getting the whole dose because anything that's absorbed in the duodenum goes straight to the liver.

**Peter Attia** (2:34)
So how much fiber is in an apple?

**Robert Lustig** (2:36)
A lot. I mean, I can't give you a bunch.

**Peter Attia** (2:38)
But I'm just directionally making this number up. But let's say there's, how many grams of fructose in an apple? 20?

**Robert Lustig** (2:43)
There's 30 calories in a standard apple, half of which would be fructose of 15

**Peter Attia** (2:49)
That seems low. An apple like a big-ass Fuji apple?

**Robert Lustig** (2:52)
Well, I mean, not a big mother apple, but like an apple apple.

**Peter Attia** (2:56)
But so based on that, you're saying only half the fructose that you would eat in a piece of fruit might actually get to the liver?

**Robert Lustig** (3:03)
Yeah, or less.
Most of it's going to end up in the jejunum, and once it goes to the jejunum, it's a free-for-all. Do you absorb it or do the bacteria digest it and metabolize it for their own use? Remember, you have 10 trillion cells in your body, but you have 100 trillion bacteria in your intestine. Every one of us is just a big bag of bacteria with legs. Those bacteria have to survive.

**Peter Attia** (3:24)
If the fructose gets absorbed at the level of the jejunum, in other words, if the gut outcompetes the bacteria, can it still get back to the liver?

**Robert Lustig** (3:30)
Oh yeah. Yeah, but the area under the curve will be wider, which means the insulin response will be lower, which is what you want, because it took longer. But a lot of it won't get absorbed. It'll be digested. It doesn't come out in the stool. It gets digested by the gut bacteria who use it for their own purposes. Now, here's the thing that I only learned about a month and a half ago, which is absolutely essential.
If you don't consume fiber, that means that your gut bacteria are not getting the food they need because you're absorbing it all early. Well, they still have to survive. So what do they do?