I tried it several times over the weekend, with at best mixed results. If course, the first thing is that with only one content citizen, you have to up the entertainment slider, and unless you are on a river, the worker isn't even contributing to that expense. You won't even get the road to help out. So science is much slower than would otherwise be the case.
This, of course, means the first couple warriors will be MPs rather than explorers. Hope you are expansionist, otherwise you have several more turns before another warrior pops out so he can do some exploring.
OK, assume you lucked out and picked the right direction with your explorer. When your settler pops, he's going to walk 3 turns or more, rather than the 1-2 he would otherwise have.
So when didn't the start bite? Hard to say -- I couldn't rerun the scenario and pretend I didn't know where I wanted my second town. I'm pretty sure I got my settler out earlier when I was on grassland with a few bonuses. I'm pretty sure I was slower when there was bonus food I could have irrigated. I was ahead with starts that were mostly hills, mountains, forests, deserts and plains that I could not irrigate. I think I was about even on jungle starts.
Basically, what I found was that on a map I would ordinarily Ctrl-Shift-Q, its possible to make it play a little better than it otherwise would. I'm not sure I would even consider it then unless I was expansionist, but since I don't really like expansionist, I'm likely to Ctrl-Shift-Q.