Ouch, no food for eight days? Do you not feed your cat or dog for that period while you're away? How about yourself?
While I know I'm not comparing apples to apples here, most fishes are eating food all day long, constantly grazing the reef. I suppose with minimal fish stocking and lots of natural food sources you could get away with it, but I wouldn't recommend it in most tanks.
Several of my clients tanks in offices have had major issues from not being fed over a weekend. Fish start to be more aggressive defending their territory when food is not around, resulting in badly beaten fish or death.
I agree to not put any type of feeding block into a tank. However there are some affordable dry food auto feeders out there, or better yet you can pre-portion an all-in-one frozen food like LRS and stick in your freezer for a tank sitter to toss in once or twice per day.