The second necessity in line. Water. You have about three days without this much needed element, and three miserable days they will be.
This one is sneaky. The suggested daily amount of water seems to be vague and that doesn't take into account many factors. How much did you sweat today? Did you eat/drink anything that is increasing dehydration? Height/weight? How much water was in the foods you ate?
The reality is that you really don't even need to think about it too much and you'll still survive, but will you thrive? I've always heard about mineral depletion in the body but it was only recently that I started looking into it. Again, the goal here isn't to give you a blueprint on what to do but to inspire you to do some of your own research. What I discovered is that we used to get a good portion of our minerals through our drinking water but this is when we could drink fresh water from the earth. This isn't an option for most of us anymore so all of that "pure" water you're drinking is most likely lacking in any minerals, and the more you drink, the more you flush from your body. Forget about it if your hydration source is from soft drinks or any variant...pretty much poison. I'm trying to stay off my soap box here but I get passionate when it comes to food and beverage. I'm not a nutritionist, just a guy who's been obsessed with what he eats/drinks for around 32 years. It's been a work in progress and it took about 30 years to figure out what works best for my body, but don't let that discourage you, I didn't have the internet when I started.
So what's the takeaway I'm hoping for? Keep coffee and tea to a minimum (I do around two cups a day) and try to get rid of anything else. Look into mineral supplementation to add to your daily water (check with your doc if you're into that) and find the balance you need as an individual. We are all drastically different with our needs so there is no perfect formula, but this can be a starting point to thriving.