"Thus, having a lobster on a Friday night is really not a fast...."
Darn! Another plan down the tubes. :(
I know ... bummer. But, interestingly enough, it didn't used to be that way. Early Christianity didn't have regulated fast, although twice weekly was always kept from Judaism. Slowly, the type of food and periods of fast were set by the Church. Monastic fasts were stricter and longer, but eventually everything evened out. Monastic orders maintain their own regimen nonetheless.
A fast is a true fast when it comes from the heart and not when it is an obligation imposed from the outside. As long as it represents obedience to someone else's directives, and is perceived as such, it is not a fast. Especially if it is done out of fear of retribution for disobedience.
I am certain that once the heart decides to fast, fasting ceases to be an obligation and it turns into a prayer. When that happens, all temptation ceases and all cravings disappear. I think the way to proper Orthodox fast is a matter of theosis, and how we experience fasting is a reflection of our position on that ladder.