...and undeniable.

We asked four people to drink only water...

for one month.

Monster headaches.

I'm so tired.

Lashing out.

We want fucking water!

Stop torturing me.

This is a psychological component.

I might die doing this. I literally might die doing this.

Coffee is life. Life is coffee.

Like, on a normal day, I'm dehydrated.

I'm probably dehydrated right now.

I don't know how to watch Netflix without wine.

I'm addicted to coffee. I love soda on the weekend.

I really hope to not be dehydrated all the time.

I'd like to know what it feels like to feel healthy.

I wanna be not addicted to caffeine.

I feel really sluggish in the afternoons around 2 or 3,

and I'm hoping that maybe if I just go all water

I'll have some more energy.

I can do this, 100%. (laughs)

Good morning, everybody.

So, got my water, I'm ready to do this,

I'm feelin' pretty good.

Actually, I'm pretty excited. Let's do this!

Healthy living: day one.

It's day three. I feel like I'm dying right now.

Can I chew, like, coffee beans for caffeine?

I went into this really confident, but this is actually

one of the hardest things I've ever done.

I'm so tired. And all I wanna do is drink coffee.

I have had a ton of withdrawal.

I just feel terrible.

Monster headaches,

lashing out at other people for no reason.

To me, I feel like this was probably the toughest week.

Cause it was the change.

I feel like now I'm sorta getting used to not having tea.

But the biggest bummer, I think, was socializing.

David. How's that water thing coming, buddy?

The water thing is just great,

and I was just getting some water right now.

Which water were you gonna get in there?

And don't you guys have jobs or something?

Don't you have jobs? Get to your jobs.

Eating and drinking are so tied to my social life.

It's difficult to be at breakfast and just drinking water

and everyone else is drinking, like,

a coffee or some orange juice.

This challenge is the worst possible thing.

I've gained weight.

The fact that I'm drinking so much water

makes me feel entitled to make choices like nachos.

I guess when I came into this I was kinda hoping

that I would notice more energy,

or notice something significant about the way I feel change

and that hasn't happened.

I also haven't been super good about not drinking alcohol.

I just wanna have fun on a Friday after the difficult week

so I've had a few drinks. (buzzer)

and then I went to karaoke and

(buzzer) drank a lot. (laughs)

Proper hydration can lead to improved physical performance.

So we're gonna play some kind of

weird mash-up of Capture the Flag and tag?

I feel okay, I feel pretty fine.

I'm not too tired, so maybe I have been

a lot more hydrated these past three weeks.

Since I've started the only water thing, I have noticed:

the wall I hit at 3 or 4 pm has kind of gone away.

I've been managing my sleep better,

so I force myself to go to bed at a certain time

if I know that the next day I have to get up early.

Cause usually I'll just like use coffee to cover all that up.

I also didn't realize just how often in my life

alcohol is just around, and more often than not, free.

In this past week I was at three different parties

where people were offering me lots of free alcohol.

Stop torturing me.

This is way harder than I thought it was going to be.

This is just, this has been the worst.

Post-Water

I'm about to explode with happiness. Oh my gosh!

It's been a long time. (sighs)

This is great.

It is before 11:30 in the morning.

It's one week out and I feel tired, still, all the time.

I feel like coffee should really affect me now,

but I feel like now I'm just desensitized to it.

Doing this life change was really good

because now any future life changes I wanna make

I'm a little more prepared for.

My base lesson is that water should be

what you drink as a baseline.

I can't tolerate coffee anymore.

Which is so sad and so difficult.

You're forcing me to be hydrated

and not have an excessive amount of caffeine.

You... You messed with my life.

(laughing) You've changed my life.