This is a partial transcript from "The O'Reilly Factor," March 19, 2004 that has been edited for clarity.
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BILL O'REILLY, HOST: In the "Back of the Book" Segment tonight, Americans drink billions of gallons of diet soda a year. It's incredible how much we consume. And some believe millions of Americans are addicted to the stuff. They have to have it.
With us now is Dr. Shari Lieberman, a certified nutrition specialist here in New York City.
All right. So it's -- 10 billion cases of soda sold every year in the USA, and 30 percent of that, approximately, is diet soda, and I know people who walk around all day long drinking diet soda. What is that all about?
SHARI LIEBERMAN, PH.D., CERTIFIED NUTRITION SPECIALIST: It's unbelievable. It is such an addicting substance. You have both the aspartame, the NutraSweet, combined with the caffeine. You're basically getting a rush all day. It actually messes with your brain chemicals, Bill.
O'REILLY: Does it really?
LIEBERMAN: It really does. You know, aspartic acid actually makes what we call excitatory neurotransmitters. Imagine we have a balance of ones that calm us down and ones that hype us up.
So, if you're drinking something that's going to make the ones that are excitatory or making us hyper all day long, that's why there are so many side effects associated with NutraSweet, such as irritability and anxiety.
I mean people are basically getting a rush all day from drinking this.
O'REILLY: OK. So, if you're drinking diet soda all day long or, say, you're drinking, you know, 48 ounces, 50 ounces a day, which a lot of people do...
LIEBERMAN: They do.
O'REILLY: ... you are basically -- it's an upper.
LIEBERMAN: It's an upper. Exactly. And guess what happens when you run out of it? It's a crasher...
O'REILLY: Is that right?
LIEBERMAN: ... and then you need an upper.
O'REILLY: You feel bad after it.
Now is this physically addicting, do you believe, or is it psychological?
LIEBERMAN: I believe it's physically addicting. You know, we know that caffeine is. So you've got a ton of caffeine in the diet sodas. Then you actually have a substance that's affecting neurotransmitters. So they're really getting a double whammy, and, of course, we're talking about people that are drinking it all day long.
O'REILLY: Yes, and they think that, well, I can drink it all day long because there's no calories in it, I'm not going to get fat. Go ahead.
LIEBERMAN: I have to tell you something about that. If you look at the research, people that drink diet sodas are oftentimes eating more calories than people drinking regular sodas.
O'REILLY: But they're eating them.
LIEBERMAN: It actually increases...
O'REILLY: You know, that's -- they're eating.
LIEBERMAN: It seems to increase...
O'REILLY: You can't get fat drinking diet soda.
LIEBERMAN: It's not that you get fat, Bill. I think it's the...
LIEBERMAN: ... taste of the sweet. It keeps you so addicted. They seem to eat more carbohydrates throughout the day when they're drinking diet soda. Go figure.
O'REILLY: What other physical things -- if you're consuming a lot of diet soda, what happens to your body?
LIEBERMAN: Well, you also can get a certain amount of methanol, which is the more toxic alcohol. That's a byproduct of NutraSweet and aspartame, if you're drinking a lot of it, and that's a wood alcohol that's actually rather toxic and can cause some problems as well. So you have a substance that, when you're taking in really large amounts, is going to affect your chemistry, your brain chemistry, your...
O'REILLY: Your body chemistry and...
LIEBERMAN: Exactly. Your body chemistry.
O'REILLY: OK. Now there are no warnings on any of the soda labels, and nobody says any of this. But, you know, I -- and I wanted to do the story because, anecdotally, I've seen people, you know, in the office here and all of that, drink diet soda after diet soda after diet soda.
LIEBERMAN: Well, who did my makeup today actually said to me she's drinking a ton of diet soda and is suffering from migraines. There are reports of migraines and fibromyalgia and certain illnesses disappearing when people go off diet sodas. So, I mean, there is a relationship between taking in a lot of this stuff -- we're not talking about the occasional user.
LIEBERMAN: But if -- you know, once again, you've got these excited neurons in your head, and it is related to migraines and fibromyalgia and a number of other illnesses that have been shown to go away.
O'REILLY: Right. And it doesn't do any -- your teeth any good either?
LIEBERMAN: It really -- it doesn't protect your teeth like Xylitol and some of the other sweeteners.
O'REILLY: All right, Doctor. I knew drinking 50 ounces of that stuff wasn't good.
LIEBERMAN: You were right, Bill.
O'REILLY: You know, one Dr. Pepper once in a while, fine, but, you know, leave the six-pack home.
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