[gojomo]

Caffeine and phenylalanine, in addition to the sweetness-without-actual-energy that is likely backfiring to create further sweet-cravings.

(I wouldn't be surprised if research eventually concludes regular Coke is safer than Diet Coke, even given the problems with HFCS. So, if trying to quite Diet Coke, you might 1st want to try substituting regular Coke... which you might find more satiating and thus consume less of, by volume.)

[jheriko]

I'm not sure you can describe an essential amino acid as an addictive substance... sure there is a strong desire to consume it, but its closer to things like oxygen, water or any vital thing that keeps you alive.

Caffeine on the other hand has a well understood and documented mechanism of physical dependence, but its considered extremely mild compared to substances traditionally considered addictive (nicotine, alcohol)...

[gojomo]

Do people crave phenylalanine beyond the essential levels needed? There's strong hints some do, via both diet sodas and sugar-free gums. And there's a plausible mechanism, given phenylalanine's relation to key neurotransmitters, and its use in treating depression and other neurologic disorders.

(I suppose we could raise the same question about food in general. Obviously food is necessary, but can it ever make sense to talk about a 'food addiction'? Or perhaps more accurately, an 'overeating addiction'? I think it can, in some cases. For someone wondering why they feel 'addicted' to diet soda, the high levels of mood-altering phenylalanine from the aspartame is highly likely to be a factor.)

[jheriko]

we are still comparing apples and oranges even with your argument...

[beat]

I don't have much of a sweet craving. I turn down dessert much of the time, don't like candy generally.

What Diet Coke makes me crave is starches - "crunchy salt" in my wife's parlance. Potato chips, popcorn, crackers, stuff like that.

[cpeterso]

Yep, there are a couple recent studies showing diet sodas have no weight loss benefit over regular soda.

[sten]

Well it does, if all else is head steady. But the issue seems to be that nothing is held constant in reality and the missing sugars are made up for with snacks elsewhere.