The Game Theory of Weight Loss

A lean runner is a fast runner. While working out helps get there, a lot of being in good shape is about eating right – and it’s something most of us struggle with. I tried out a new strategy over the holidays – read about it below.

Crossposted from

The fun thing about Game Theory is that it can be applied to pretty much anything: buying decisions, Tic-Tac-Toe, traffic problems, etc. That means it can also be applied to dieting and weight loss.

That’s the premise behind DietBet. Here’s how it works: you bet $20 [or some other amount] that you can lose 4% of your bodyweight in a month. Other people also bet $20, and that money all goes into a pot. At the end of the month, whoever loses 4% splits the pot.

Early December of 2012, I decided to try it out for myself. I paid my $20, confirmed my weight, and off we went.

The psychology that’s at work here is called loss aversion: “people’s tendency to strongly prefer avoiding losses to acquiring gains.” More simply – I really don’t want to lose that $20.

Throughout the holidays, I thought about that $20. Eggnog? No thanks. Is that extra serving of turkey worth $20 to me? I don’t think so. Delicious, delicious chocolate cake? So tempting … but so is not losing $20.

I also thought about my anonymous competitors. If that guy who thinks a 20-minute workout is good enough wins, and I don’t … well, that would just be silly.

Over the course of the month, I exercised and watched what I ate. Having money on the line made it a much more compelling prospect.

At the end of the month, I weighed in – and made weight. I split the $3,000 pot with several other winners, and got back $52. Not a bad return on investment.

The idea of betting a friend, or a few friends, to create an incentive to change behavior isn’t new. There are a lot of weight loss specific games like this out there – FatBetStikk, just to name a few. I picked DietBet because one of my friends posted about it on Facebook.

I’ve put down money for a January weight loss bet, too. It will be a little more difficult this time around, as the “easy to lose” weight has already come off. But the stakes are higher this time. For January, I reinvested $50 of my $52 winnings. Now, I’ve got $50 to lose.

The pot for this game is obscenely high – around $65,000 (you read that right). So the upside is enormous, too.

That being said, I saw a game with a $300 buy-in. That’s a lot of money to have on the line … it sounds like a good incentive, but maybe too stressful to think about for a whole month!

Check out DietBet at Post isn’t sponsored – just sharing a fun story. :o )

The Game Theory of Running

[originally posted at]

Running is all about economics.  During a race, every decision is a cost-benefit analysis.

Here is a hill.  Do I run it to shave a few seconds off of my time, or walk it to avoid the risk too much lactic-acid buildup?

Here is another runner.  Do I make conversation over the next few miles, or save my breath for that next big hill?

Here’s an aid station.  Will the marginal Shot Blok or Gu give me an additional boost, or will it mess up my stomach?

Every choice can be modeled as a decision tree.  There’s a rock in my shoe.  Do I take two minutes to retie it and make up the lost time later, by running faster? Or, do I suck it up for the next 16 miles and face the blistering consequences for the next few days?

Every mile becomes a mathematical calculation.  I’m 18 miles in.  I’m running 26.2 miles today.  I’m a little less than two-thirds of the way through this race.  Without a calculator, I’d guess that’s about 60 percent completion.  Either way, I’ve got about eight miles to go.  At this pace, that’s around 75-80 minutes.  Can I keep this pace up for that long?  If I run a bit faster, I’ll finish faster; could I finish in 70 minutes?  That’s still a long time to be running.  How far until the next aid station?  That’s closer; I’ll think about that instead.  Am I at 19 miles yet?  What percentage of the way through is that?

I spent about 300 hours running last year.  That’s a lot of hours.  And that’s only the physical act of running.  This number doesn’t include thinking about running, reading about running, writing about running, or preparing for running.  I don’t even want to know how many hours that would be.

Like any activity, running has an opportunity cost.  What could I have been doing yesterday for five hours instead of running?  What could I have been doing last year for 300+ hours instead of running?  Could I be out meeting new people? Working on a project? Would I know how to speak Russian by now?

Not only that, but I’m a young runner, especially for the distances that I run.  Does waking up at 5am every day have long-term negative effects?  I’m already suffering knee problems; when will I have to get knee replacement surgery?  Next year?  In ten years?

Every so often, I think about finding a new sport, or a new hobby, that would replace running.  But then I think about the value I get form the sport.

On a quantitative level, my blood pressure is low.  My body-fat percentage is low.  My LDL, or “bad cholesterol,” levels are so low that most basic machines can’t even calculate it. My resting heart-rate is low.

Those sorts of numbers are nice, but they aren’t really enough to get a runner through several hours of nonstop athletic activity.  The qualitative, immeasurable benefits are what keep us coming back.

Because I run in the morning, I probably see more sunrises in a week than most people do in a year. I spend time out in nature almost every day – time that would otherwise be spent in front of a computer.  And nothing compares to being alone on a mountain listening to the quiet orchestra of nature: the whisper of waves in the distance, the hum of wind through the grass.  Add in the percussion of your own rhythmic breathing and 4/4 footfalls, and it’s a veritable symphony.  Not only that, but vacationers travel thousands of miles for a view like this.

So, I’ve done the calculations.  Multiple times – I’ve had a lot of hours in which to think about them.  And, at least for now, the benefits of running outweigh the costs. In terms of monetary output and time, I’m happy with running’s return on investment.

See you on the trails.