Crossposted from

Dieter: Dude, we’re fat. We should do something about it. Anything at all, really. How about we stop eating refined carbs from animal sources between 2-7:15 pm each day?

Dad bod: How about we don’t do that? We’re spending so much energy thinking about diets you’d think that activity by itself should make us lose weight. And yet, like everything else we’ve tried, it doesn’t. Maybe we should face reality and accept that the pounds are there to stay.

Dieter: You mean give up like a lazy fat loser?

Dad bod: More like optimize allocation of self-improvement effort to more fruitful pursuits.

Dieter: I was going to start calling you names, but that’s not going to help us have a conversation. How about we introduce ourselves instead? I’m the part of Jacob that hates being overweight and thinks we need to take dieting more seriously.

Dad bod: And I’m the part that thinks dieting involves a lot of suffering with no payoff, and that it’s perfectly OK for Jacob to keep living inside a portly dad bod.

Dieter: “Portly”, huh? Curious that you didn’t go for any of the less dignified synonyms, like “pudgy” or “chubby”. Let’s start with the facts: Jacob is 185 lbs at 5’9″, which comes out to a BMI of 27.3. That’s smack in the middle of the “Overweight” BMI range.

Internalized Scott Alexander: You know BMI isn’t very scientific, you should measure your body fat composition and lean muscle mass…

Dieter: Shut up, Scott. Jacob is of average height, has an average body type, and his bones aren’t made of adamantium. We’re right in the middle of the range that BMI is calibrated on. We’ve been avoiding doing body-fat measurements because we’re afraid of seeing the results. Would anyone here not press a button that would make Jacob weigh 165 pounds tomorrow?

Dad bod: I would press that button, but it probably doesn’t exist. Jacob was 165 lbs at age 18 at the end of combat boot camp, and since then has been steadily gaining 2 lbs a year. There has been almost no variation around this slow trend-line. Diets, exercise plans, changing countries, dating super fit girls and curvy ones – none of that has made any measurable impact at all. Since hitting age 30 we seem to have stabilized around 185 lbs. So why do we keep wanting to “do something about Jacob’s weight”?

Dieter: Have we ever really tried a diet plan? Communism has been tried and found wanting, but dieting has been found difficult and not tried. At best, we half-assed things like calorie counting and carb restrictions for a few weeks at a time. An every-other-day diet is no diet at all, since all gains are immediately reversed. We must stick to something at least long enough for the expected weight change to be measurable.

Dad bod: But a diet we can’t stick to is, in fact, a failed diet. There’s no dial in Jacob’s head he can turn up to increase willpower. If our track record is half-assing diets for a few weeks, then the outside view says we should predict future diet attempts to follow the same path. Even worse, we’ve tried most of the really obvious things and have grown more skeptical. We should expect to have less dieting willpower in the future, not more.

There are two more reasons why I don’t believe we’ll find a diet that works. First of all, nutrition science is a hot mess. There seems to be an equal number of arguments on each side of any dieting question. Is sugar the enemy or is every calorie a calorie? Should we cut carbs, cut fat, or cut interesting food? Snack to maintain metabolic rate or fast twice a week? Eat food, not too much, mostly plants or eat meat, not too little, mostly fat? Any signal is overwhelmed by the noise.

Another reason for diet-skepticism is observing people around us. Jacob’s friend Charlie weighs around 100 lbs but eats more calories than he does each day. I think that she started escorting not for the money but just to try all the steaks and lobsters in Manhattan, and she quit escorting when she got bored of ordering three entrees at Michelin restaurants.

If we ate like she does we’d assume a perfectly spherical shape. 185 lbs is probably as thin as this metabolism gets.

Dieter: Sure, let’s talk other people. Have you noticed that practically no one you hang out with is obese? Jacob doesn’t really care, and all his social circles filter heavily on cognitive ability and intellectual interests, not on appearance. And yet by some mysterious process, every person you meet in those circles isn’t fat. Were you really born with the slowest metabolism of any person in your social class, or do other people actually take this more seriously?

Dad bod: Fair point. But if our social life doesn’t depend on being skinny, why bother? It’s not clear that a BMI of 23 is healthier than 27, and Jacob is in decent shape functionally. When we play soccer, Jacob not only has the energy to run back on defense every time but also to yell at his teammates for not doing the same.

Dieter: Imagine playing soccer with a 20-pound weight strapped around your stomach. That’s what we’re doing right now. Doing a ton of sports while fat probably built up some impressive muscle underneath the adipose tissue. Let’s unleash it!

And speaking of soccer: I don’t feel the extra pounds while running back on defense. I feel them when we decide to play shirts vs. skins and I get that sudden rush of panic thinking I may have to take my shirt off.

Dad bod: That panic is just in your head, nobody else really cares. What if you just stopped worrying about how you look like with your shirt off?

Dieter: If we “just stopped worrying”, how soon would it be before I hit 205 lbs? When that happens, the panic will be there every time I undress to take a shower and have to see myself in the mirror, instead of every other week.

Dad bod: It’s hard to argue when you have both hope and fear on your side. Let’s deal with them one by one. What would make you give up on dieting?

Dieter: If we actually full-assed a diet for a long enough period of time and didn’t see any improvement at all, I’ll probably give up. If we make an unusual effort I’ll know that in case we fail we’ll never be able to summon the same effort again.

What would convince you that dieting is possible?

Dad bod: I think if we ever actually saw a result, that would give me all the motivation and belief I need. Until we see it on ourselves, in the mirror and on the scale, our System 1 will never believe that dieting works no matter how many people tell our System 2 about their slow-carb-paleo schemes.

Scott: Sounds like you’re both ready to stake a bet on a scientific experiment! Dieter, what do you predict?

Dieter: I think that we can lose at least one pound a month by committing to a reasonable diet. A 4-pound shift should be visible over a regular day-to-day fluctuation of 1-2 pounds, so we’ll need to diet for four months.

Dad bod: Fair. I predict that doing a diet for four months isn’t going to make Jacob lose 4 pounds. What should we try?

Dieter: We’ll do intermittent fasting: only eating within an 8-hour window every day, plus counting calories to stay below our total daily energy expenditure. People also say that sugar is bad so we’ll try to avoid sugary foods, especially in the morning. And full-assing means we’ll have to actually do the thing at least 6 out of 7 days each week.

Scott: Wait, are we doing intermittent fasting just because a couple of friends and a podcast mentioned it? That’s not rigorous! We should do a meta-analysis of nutrition approaches, cross-reference them with how well the subjects match Jacob’s variables…

Dad bod: Shut up, Scott.

Dieter: Yeah, if there’s anything Dad bod hates more than doing dieting is researching diets. If we start digging into books, we’ll never get to the actual thing. Hopefully, this is the sort of diet that can establish some healthier habits even after we no longer track it.

Dad bod: Also, intermittent fasting does seem easier to implement. It’s not hard to lie to yourself about portion size, but 8 pm is 8 pm.

How do we make sure we actually stick to the diet for four months? I would currently bet on us making it 6 weeks at most.

Dieter: With Beeminder, of course! Here’s the diet tracker goal, with an explanation of the point system. I get a point for each day that we stick to the 8-hour window and the calorie limit, and lose points for going over. The goal is also public, so all readers including my mom can see both my weight and how well I’m sticking to the diet. If on August 1st I weigh more than 183 lbs, I’ll be ready to give up on the enterprise.

Dad bod: And if we go below 181 for several days straight, I predict being excited enough to keep at it. If we fail to actually implement the diet or end up at 182.5 lbs after four months of suffering, I guess we’ll be back to square one.

I’m still not sure we’ll be able to stick to this plan for four months, and I don’t feel internally surprised when I visualize us utterly failing and giving up with a bunch of excuses around early June. On the other hand, the combined incentive of social pressure, scientific rigor, and the chance to shut you up once and for all is motivating enough that I won’t be shocked if we succeed. 

Good luck, psycho!

Dieter: And same to you, fatso!

I conducted this conversation between parts of myself during a mentor’s workshop at the Center for Applied Rationality, and it involves a few CFAR techniques. I'd also like to thank the following CFAR mentors:

  • Qiaochu, who encouraged me to write more vulnerable things on Putanumonit instead of just building models for fun.
  • Mr. A, who talked with me about dieting and also encouraged me to dive into topics I’m uninformed on and could look stupid writing about.
  • Ms. L, who transcribed this conversation as I was having it out loud. Ms. L misheard “Dad bod” and thought that I named the anti-diet voice “Dead body”. She stuck to her job as facilitator even as she grew increasingly confused about why I’m talking to a corpse.
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Very glad to have some examples of Internal Double Crux, as well as appreciating the vulnerability here. Kudos!

If we “just stopped worrying”, how soon would it be before I hit 205 lbs?

That sounds like a way easier hypothesis to test than attempting to lose weight. And imagine the upside if that hypothesis turns out to be false!

My understanding is that fat cells divide upon growing too large, but don't meaningfully die or merge upon growing too small [see here for a simple statement of the claim]; that means the heaviest you've ever been is an input to all future weights. So the upside is nice, but the downside seems bad enough that it's not worth testing.

Created an account, because finally, something I can speak about from firsthand knowledge!

For a quantitative person it's helpful to check your weight on a regular schedule. For me it's every morning after waking up, before consuming anything (water, food). It's the most consistent time. This gives a reward for your work immediately, especially because the first week or two you may lose water weight as glycogen stores deplete (each 1 gram of glycogen lost also gives up 4 grams of water, you may lose ~1lb of glycogen). Sure it's just water loss, but you look better, and fit into your pants better, and it's encouraging.

The part where diets fail is in maintaining the weight loss. This is where weighing yourself regularly becomes even more important: Have a target weight that you actually can hit and strive to maintain without excessive willpower (say 170). Once you're below 170 you can eat more freely within reason. But always have an "action weight" (say 175) where if you go above, you start watching what you eat more carefully until you're below 170 again.

It's not "weight loss" it's weight maintenance.

Reading this makes me curious whether there's a part of you that actually prefers being at this weight. Did you try to listen for such a part?

I tried after reading your comment. I didn't hear anything. I can't think of a single reason why I wouldn't want to lose 20 pounds, or feel any part hesitating before pressing a magical button that would allow me to do that. If it's there, it's hiding really deep.

Promoted to frontpage.


Just figure out the difference between wrong and fun. That's the key to so many things in life.