[Seanette]

Alcohol is addictive, and can lead to the user harming those around him/her (trust the daughter of a violent alcoholic on this one). I'm not sure how a "live on pizza" type is likely to, while under the influence of pizza, turn violent toward family members, crash his/her car, lose judgment sufficiently to engage in sexual indiscretions, etc. (Side note on DUI car crashes, from police: the DUI driver is more likely to walk away than his/her victim.)

Tobacco can also have detrimental effects on people who have to be in the same room with a smoker (and smokers do have a higher risk of setting the house on fire). Addictive, too.

Tea and coffee don't much impact the people around the user, granted, but can be addictive (this from someone who really needs to cut down her caffeinated soft drinks, I must confess).

Also, all the above-named substances can be rather expensive, for negligible at best health benefits, and the resources involved in producing and consuming them could very likely be better directed into more beneficial items.

I'm not too inclined to start hyper-analyzing why the Lord has set the standards He has, since I trust Him to know what's best, what with that omniscience deal. I do worry that things like Mountain Dew and chocolate may wind up on the prohibited list, but if that happens, I'll suck it up and obey.