Yes, there are a few obvious similarities:
* Both often involve budgeting and tracking the balance between your intake and your expenditures.
* Both (arguably) draw on the same limited self-regulatory resource.
* Hence, both benefit from the development of implementation intentions, rules, and good habits.
But the differences loom large to me:
* Tracking calorie intake and expenditure is infinitely harder than tracking money. With calories (or carbs or fat grams or whatever), it is impossible to be accurate.
* Going on a spending fast, like Operation Cheap Ass, does not have weird negative consequences for your ability to earn/spend nor for your life overall. You can do it for a while, stop, and pick up your life where you left off. Going on a severe diet screws up your metabolism and can lead to serious health problems.
* Once you get out of debt and start saving money in an interest-bearing account, the money you have multiplies without you really doing anything. The more successful you are, the more successful you become. A virtuous cycle emerges. You end up with more money to spend on more things. Once you lose your extra weight, your body burns fewer calories than before. The more successful you are, the less successful you become, in a sense, because you have to reduce your net calorie intake to maintain a given weight.
* When you get older, there are some things you can get for less money with your "senior discount." This lets you consume more. When you get older, your metabolism slows down. This forces you to consume less.
One pet peeve of mine, that came up in the comments of those blog posts, is the idea that physical and financial fitness both boil down to delayed gratification. Am I missing something or is this a wrong-headed idea?
If you are in the black financially, then yes, to a certain extent you can make delayed gratification work for you. You have $1,000 to buy a stereo but instead invest it so that later you have $1,000 to buy a stereo plus $100 (or whatever) to buy music to play on it (assuming your interest > inflation for those goods).
But even if you are in the enviable position of already being at your ideal body weight / strength, you don't earn interest on "unspent" calories. I don't think there's any reason to believe that if I "saved" 500 calories per day for a month that I would be able to spend those 15,000 calories plus another 1,500 calories at the end of the month (on a cruise, say) without ending up weighing more than I started the month with. I mean, yes, I can delay the gratification, and given the circumstances it might make a lot of sense to save calories from my daily allotment toward a calorie-bash later, but I don't end up being able to consume more overall.
And if you are trying to lose weight or get out of debt, you do not have the luxury of delaying gratification. You are in the sucky position of needing to forgo gratification. You've already spent too much money or eaten too many tasty treats and now you have to pay the bill. While there may be some psychological self-regulatory advantage in telling yourself, "I am going to eat / buy this desirable thing tomorrow," and having tomorrow never really come (like Alice's jam tomorrow and jam yesterday but never jam today dilemma), it's just a trick to get you to cut your consumption. This is not a "think of the one pretzel as a dry stick to keep yourself from eating it now so you can get a double portion in a little while" delayed gratification situation. If you are trying to lose weight / cut debt, you have to avoid consuming the one pretzel, full stop.
I have to assume that in many cases, people suggest that delayed gratification is important because they are thinking not of one pretzel today, two pretzels tomorrow, but trading the gratification of consumption today for the gratification of fitness way down the line. Now you're looking at two qualitatively different sources of gratification. I am probably just splitting hairs, but I'd like to think of this in terms of managing across short-term goals (I want to consume now!) and long-term goals (I want to be healthy/thin/rich) that are in competition rather than calling it delayed gratification (which is just a matter of time).
Impenetrability.
`Would you tell me please,' said Alice, `what that means?'
`Now you talk like a reasonable child,' said Humpty Dumpty, looking very much pleased. `I meant by "impenetrability" that we've had enough of that subject, and it would be just as well if you'd mention what you mean to do next, as I suppose you don't mean to stop here all the rest of your life.'
Sadly, no. Next, I am going to analyze some data and write up Experiment 2.