I Quit Coffee for 90 Days - Here’s How It Affected Me as a Software Engineer

Date: 2025-04-25 | coffee | productivity | reflect | simple-scalable-systems | software-engineering |

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I quit coffee in January after a friend quit and said it was beneficial. It's now been 90 days and I've seen some substantial changes so thought I'd share my experience and how it's affected me while I can still remember the before / after of what it feels like.

My Background

A little background about me - I've worked professionally as a software engineer since 2017. I've been an avid coffee drinker for the last ~decade, often drinking 2-3 cups a day.

  • Morning: Large iced coffee (Dunkin) - ~398 mg caffeine
  • Lunch: Small coffee - ~95 mg caffeine

This puts my daily caffeine intake just under 500 mg a day.

In the past year I started getting into teas (Liquid Death iced teas) and would often drink that in early afternoon which adds another ~30 mg per day.

Caffeine has always been a tool for me to get focused ("locked in" as the kids say) on my work. In college I used to drink white Monsters during study sessions. In my professional career, I used coffee alongside my productivity blocks to get in the zone to finish my daily tasks.

This code and coffee mindset is pretty common I think and tbh is something that worked well for me for years.

Why I Decided to Quit Coffee

I am pretty open to trying new things with my life if I think it may make me happier, healthier, or more positive - even if that move seems drastic from the outside.

Recent examples:

I'd been thinking about reducing my coffee intake for awhile - especially as friends and family have noted how much more coffee I drink than normal.

In January one of my close friends told me he had quit coffee a few months prior and now felt smarter and more productive than before. He's one of the best software engineers I know and really focuses on the impact of things rather than hype so generally trust his opinion when he shares results of doing something.

This doesn't mean I go for everything. He also said that creatine made him smarter (which some studies actually back up) and moved to a near nocturnal sleep schedule (getting up ~1600) both things I've stayed away from.

I read up on other ppl's experiences (esp r/decaf) and was intrigued by some of the anecdotal benefits of lowering / removing caffeine intake. So with some more evidence that perhaps it was beneficial to lower caffeine intake, I decided to try it myself.

Results of Quitting Coffee

It's now been 3 months since my last coffee. I do drink a Liquid Death tea in the morning (~30 mg of caffeine - same as a decaf coffee) but still this brings my caffeine intake from ~500 mg to ~30 mg.

Coffee Energy over a Day

Benefits

  • Get up in the morning feeling rested, often before my alarm goes off
  • Don't need caffeine in the morning to start doing things - whether it's working out or getting out of bed or starting my day
  • Less activation energy required to start a focus session
  • Anxiety in the evening reduced by ~80% - less spiraling and doom scrolling
  • Get to sleep on time more often - I actually feel tired right around bed time
  • Wake up in the middle of night less

Drawbacks

I'm not really smarter or more productive. In fact I might say I'm a bit less locked in - especially for things I don't really want to do.

Balanced

Coffee tends to give a lot of drive to do something once you've had it but this drive is short-lived and tends to wear off in an hour or two and then you're left with the lower amount. So kind of high highs and low lows in terms of energy and drive.

Without coffee, energy and focus is a bit more consistent. So a bit less locked in BUT because the difference in energy / focus between different activities (even those you like and don't like) is a bit more even, it actually seems the activation energy to start is reduced further - at least in comparison to with coffee.

I find the better sleep and consistent energy / focus throughout the day has helped me to be more intentional about how my time is spent with less need to veg on the couch / doom scroll.

How was Quitting Coffee?

A big thing I was worried about was how the quitting process would be. I was an avid coffee drinker and many people report severe withdrawal symptoms from migraines to irritability to low energy / depression.

I didn't really have time to go through a depression as I was in the process of interviewing for new jobs so really needed to be top of my game (or at least able to perform decently) so decided to try quitting using my teas as a crutch if I needed it and if things went poorly would delay the experiment to a later date.

In the first few weeks:

  • Sluggish in morning - My morning workouts were hard and couldn't get through the full sets.
  • Afternoon brain fog - Kind of like a morning without coffee except it lasted all day. I could still do stuff but was definitely not 100%. Felt like vegging a lot - scrolling on my phone, watching tv, or gaming. This is often when I reached for a tea at lunch if I had a big meeting or interview.
  • Brain felt weird when trying to sleep - felt like it was sensitive or smth? Maybe this is when ppl get headaches but for me my brain just felt weird.
  • Getting tired earlier than usual - often falling asleep while reading ~30 minutes before my usual bed times.
  • Much reduced doom scrolling / anxiety at night. I used to doom scroll / plan for about an hour before bed time. But my anxiety seemed to reduce by a large amount and my mind felt tired so ended up doing that less and just falling asleep.

After a month:

  • Started to feel more normal
  • Still groggy in morning but could get through full workouts and felt awake afterwards
  • Afternoons were a little low energy but no more brain fog. Harder to get into a focus session so leaned heavily on small 30s meditations to center myself before attempting.
  • Afternoon energy was more consistent - ~same energy from ~1300 through ~1900 so basically no afternoon crash.
  • No coffee urges - though this may have been buoyed by my daily tea intake.

Now 3 months later:

  • Up as soon as I wake up - Wake up before alarm, feel awake and refreshed and ready to go
  • Do full workouts in morning - no caffeine needed
  • Focus sessions are easy to start. I still do my micro meditations to get into them but think they're just as good as caffeine-induced ones and the focus / energy lasts longer.
  • Energy is pretty consistent from when I get out of bed to a few hours before I go to sleep.
  • Scrolling urges have vastly reduced. I've even set up some rules on my phone / computer to limit the times I can use them and don't really miss them. This is smth I've tried in the past but always broke down after a couple weeks cause the urges were so high.

I'll note that I didn't have many withdrawal symptoms aside from low energy and brain fog. I think if I had migraines or depression that might've derailed my coffee quitting so this process may be different for those who have worse symptoms.

How quitting coffee impacted my Software Engineer Interviews / Tasks

My biggest worry was that reducing caffeine would impact my ability to perform as a software engineer - in particular during interviews which are pretty high stakes, high velocity endeavors.

The low energy and brain fog in the first few weeks were a problem as it was harder for me to focus in on tasks. I could get through my simple coding tasks okay but anything larger / more complex was a struggle - so I often reached for a tea. This was fine for technical phone screens but definitely later stage final rounds with 4-5 hours of back to back interviews would've been a struggle.

When I got to my later rounds, the lack of caffeine actually proved useful. This was largely because I was beyond the worst withdrawal symptoms and starting to see more consistent energy.

In these rounds, I started noticing that I was much more calm in interviews. They felt less like a stressful test and more like a typical coding challenge. Now some of this is probably also due to being more comfortable in interviews after shaking off the rust and confidence I will do well after years of working as a SWE (and this being my 3rd full time job search in 3 years) but still I think much of the calm is attributable to less caffeine in my system.

For final rounds, the consistent energy was a boon. I didn't feel the need to get a 1500 coffee between interviews and instead felt just as ready to go into the 4th interview as I did the first. Now obviously I was still tired after interviewing all day but the energy and focus was much more consistent.

So overall I'd say less caffeine was at least neutral and probably slightly positive for me in terms of coding and interviewing.

Next

Overall I think quitting coffee was good for me. I sleep better, have more consistent energy / focus, and don't really miss coffee which honestly makes my days easier (one less thing to worry about).

Now I'm not completely caffeine free - I do still enjoy my morning tea. But I feel like I do it more for a ritual and enjoyment of it, not because I have to have it to be productive.

I don't think coffee or caffeine is necessarily bad but I do think it's wise to re-examine your relationship to anything you feel you have a dependence on, just to see if a small tweak may lead to better outcomes.

As for me - I think I'm done with coffee for good.

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