Who says it is the acid that would harm you internally? It's pure sugar and chemicals.But the point it made was that your own stomach acids are many times more powerful than coke, so coke won't damage you internally.
They didn't get good results in dissolving things like rust off a bolt, but they did get good results with coke as a cleaner, especially the blood test and chrome, and the tooth didn't fare too well, but teeth never seem to hold up well.I remember Mythbusters creaming that...they didn't get ANY good results using cola as a cleaner.
Maybe I'm a little over zealous, but it will dissolve paint, I know this much, clean blood, and clean pennies. Whether or not the acid in the drink makes it bad for you is not really an issue in my mind. It's the sugar, the caffeine, the links to obesity and diabetes and in diet soft drinks the links that are only now being understood between diet drinks and irritable bowel syndrome, crohn's, and some are speculating even alzheimers.
I'm not trying to get anyone to stop drinking pop. That's like trying to get someone to quit smoking or to go out and jog.