Listen to Wolfshanze here, you really don't want to be producing NOTHING. Ideally, you stop short of striking in general. Maybe you can rearrange tiles and whatnot to get over too. Start making units then switch to others and leave them in queue, whatever.
If you're losing money at 0% science, hopefully you just completed a major conquest and are in the process of getting commerce onto your tiles before you strike. If this is the case, you should be building infrastructure buildings, then units to avoid a DoW and for HR garrison. If you're losing money without a major early conquest, you need to seriously modify your opening.
It's not always bad to be losing money at 0% though. In my most recent game (emperor/epic, small fractal map that wound up having 2 continents), I whipped out 6 elephants, 5 swords, 5 axes, and 8 catapults by 80 AD. When I attacked my first neighbor (my continent had 3 including myself), I was losing 5 GPT at 0% science, although by re-organizing tiles I was able to get +5 prior to entering enemy territory at least (forced to work tundra fur
). Razed cities I couldn't afford, kept ones that were cottaged well or otherwise powerful. Economy actually improved across the whole war - I actually picked up both currency and CoL along the way. Being ethiopia this meant cheap courthouse whipping, but also selling resources for 7 gpt.
The war never stopped. I killed the first guy then turned on my "ally", still using axes, elephants, and catapults exclusively (he had longbows and shortly into the war pikes, but so what? I had GG attached elephants!). I wiped out mehmed and was pleasantly surprised to learn that this was enough land for a 1525 AD domination - although I won lib in 1455 AD (stalin/hatsheput were on the other land mass warring also I think) and actually had over 400 BPT by the end of the game.
Always build something, and PLAN AHEAD so you don't strike...!