Why 'instead'??
I don't drink anything 'instead', I just don't drink milk, or a million other things I don't like. I don't drink any diet soft drinks, I don't drink juice, I don't drink scotch, gin, wine, etc You don't need an instead.
So what am I supposed to say?? I wake up and I think, 'wow I don't drink milk, so I better have something else instead."
Generally drink water 90% of the time, either plain tap water or soda water, or soda water with some fresh lemon added if I get bored of plain water.
On long boring road trips or or when working nights with little sleep may have some coffee, or on occasion a redbull, or small can of mothers.
When going out or having a drink it will be Beer or Bourbon, but not instead of anything.