What is moFIRE (morbidly obese FIRE) and why do I want it?

by The Darwinian Doctor

Read on to learn about “moFIRE,” the morbidly obese flavor of the Financial Independence, Retire Early movement.

This post may contain affiliate links.

I’ve been putting it off for a while, but it’s definitely time to flesh out the details of my financial plan. When I first sent my post about my spending habits to the Physician Philosopher,  his first reaction was astonishment and dismay.  One memorable recommendation was that I should stop saving money in 529 plans for my kids, because it seems like on my current path, my children will be supporting me in retirement, rather than the other way around.

As I have delved deeper into the investing and financial independence online community, the various flavors of FIRE (Financial Independence, Retire Early) have become evident.

Here’s a quick rundown of the common flavors:

Plain (vanilla) FIRE

There is of course plain old FIRE, which at its most basic level involves accumulating enough assets so one can live off the returns and “retire”.  I use quotes here, because retirement in the FIRE community seems to involve far more work and far less margaritas than one might think.

A common calculation is to multiply one’s annual expenses by 25 to reach the magical FIRE number.  This multiplier is chosen because it allows for a 4% asset withdrawal rate. This is the rate considered by many to be suitably conservative so that one’s investment portfolio could continue to grow (or at least not shrink), despite the annual 4% withdrawals.  It also hedges for leaner years of returns and also inflation.


LeanFIRE involves cutting one’s expenses to the bare minimum in order to reach the FIRE number much more quickly.  Advocates might be found wearing extra layers of clothing in the winter to save on heating costs or becoming vegetarian not only for the health benefits, but also for the cost savings.  It involves higher levels of lifestyle modification, but clearly is the fastest way to reach FIRE. Each dollar of eliminated expense is $25 less that one has to accumulate to get to their FIRE number!


In fatFIRE, one aims to support annual expenditures of $100,000 or more.  Using the 25x multiplier, this equates to a target nest egg of $2.5 million.  There is a lively community of fatFIRE proponents online. There’s even a Facebook group devoted to this started by the Physician on FIRE!

Morbidly Obese FIRE (moFIRE)

The mythical moFIRE isn’t as well defined as fatFIRE, but implies some significant margin of spending greater than $100,000 per year.  Some would suggest that any spending of $200,000 a year or more would put you into this category, provided you plan to maintain this level of spending during your FIRE years.  

I find the concept of moFIRE hilarious, and will adopt this as a worthy description of my plan for financial independence.  While humorous, it basically describes what I’m trying to do.

Why I want moFIRE

My wife and I know that we live in a part of the country where the cost-of-living is amongst the highest. We know that we could get by on much less if we moved to any of the many fine cities elsewhere in the country.

But we love where we live

For all its high taxes, Southern California offers an incredibly high quality of life. Having grown up in the frigid winters of the north east, the endless sunshine and warmth basically seems like paradise. (Ignoring the soul crushing traffic, of course.)

I also know that if we chose to send our children to public school and asked my mom to watch our one-year-old all day without additional help, my expenditures would be much less, and my saving rate would be much higher. For that matter, if we traded in our house for something half its size, our savings rate would also skyrocket.

There has to be financial balance

The Darwinian Dr-ess and I thankfully make high salaries and can afford to support our high expenditures while still maintaining what we feel to be a responsible saving rate. I’ve outlined a plan that should have us financially independent and members of the moFIRE club within the next 15 years.  

I think there are many high earning professionals out there who feel the same way I do.  For one reason or another, perhaps you cannot move to an area with lower cost-of-living or just don’t want to. I think this is where I can provide value as I outline and document a reasonable path to financial independence while maintaining a high quality of life.  

But I want to have it all!

I know that I could get to FIRE in a fraction of the time with different choices. That’s not the point. Unless life conspires to throw a wrench in my plans, I want to have it all.  I want financial independence and I don’t want to have to sacrifice my lifestyle to do it.  

Thankfully, I mostly like what I do at work. The Darwinian Dr-ess also usually feels positively about her job. We are willing to do these jobs because they offer satisfaction, purpose, and self-actualization.  The jobs also make it possible to maintain our lifestyle. However, I’m keenly aware that our current dependence on the income from our jobs is going to put us at higher risk of bitterness and burnout in the years to come.  

Feeling burnt out? You’re not alone: The Epidemic of Physician Burnout

So come along with me as I figure this all out.  At some point, I’m sure the unpredictability of life will force my financial plans to evolve again, but for now, I am satisfied to work towards moFIRE.

My next big financial post will be my projection for the next 15 years.  


Update — this post was written early on in my personal finance journey. I’ve since come to some conclusions about how I hope to achieve moFIRE more quickly. I suggest you read these posts for more details:

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5 years ago

Really loved this, and great writing!

Wealthy Doc
4 years ago

You are smart to plan for a big net worth.

Most doctors set a target too low. Then they undershoot it.

Many strive to achieve $1-2M. They feel rich with $2-3M. But if they are considering FIRE or a career change they should probably be shooting for the $5-7M range. More if in a HCOL area.

$5-7M may see ridiculously high to a starting doctor who lived fine on $60K in residency. But life happens and costs go up.

That $5-7M IRA or 401K is pretax. So after tax (24% federal and 6% state) yields $150K at 3% and $200K at 4% withdrawal rate. Either way that is an average spending level for a physician.

3 years ago

Hi there,
Great article!
Without doubt, when applying a gross number to retirement savings it has to be in the context of cost of living. Here in the UK, fat(MO)fire is a completely different number in London compared to rural England.

BC | FrugalWheels
3 years ago

Haha nice post – never heard of MoFIRE before but making up FIRE subsets is in vogue. Also, is it bad that I kept reading “Southern California” in the accent of Stuart from The Californians?

I guess the cool thing about FIRE is that it’s more of a general guiding principle rather than a hard set of dictates. It allows for an entire spectrum of approaches. I’m closer to the leanFIRE side of things myself (I don’t really feel like it’s that lean but via comparison…).

Interesting name, by the way! I’ll have to check out more posts.

Financial Samurai
3 years ago

Can you share your target number for MoFIRE and when?

Last time I ran the numbers regarding our passive retirement income in 2019, we’re at about $250,000. But I’m shooting for $300,000 – $350,000 within 5 years some how.

SF is even more expensive than LA.



[…] a grand experiment to keep our lifestyle intact while simultaneously working towards moFIRE, but it’s a work in progress.  Only time will tell if we’ll be able to pull it […]

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