My satirical talents fall far short of Jonathan Swift (see his "Modest Proposal"), so a more accurate title of this post would be "Mass In/Mass Out: Toward a Satire of Calories In/Calories Out." My aim is to provide conceptual raw material for such a satire by someone else with superior satirical and parodying talent.
Many people believe the meaning of calories in/calories out to weight loss is obvious. But in believing that, they are sneaking in an assumption that calories in an calories out are primarily governed by conscious decisions, so that the importance of physiological variation in metabolic rate and the half-conscious impact of the primal motivational forces of hunger and how energetic one feels are obscured.
One reason the rhetorical move of talking as if the meaning of calories in/calories out is so attractive is that
weight gain in calories = calories in - calories out
is an identity. So that if one can sneak in one's interpretation of what calories in/calories out means, then that interpretation can be made to seem like an incontestable principle. Indeed, people have been know to claim that their interpretation of what calories in/calories out means for weight loss is as incontrovertible as the law of conservation of energy itself (also known as the first law of thermodynamics).
In "Forget Calorie Counting; It's the Insulin Index, Stupid," "Obesity Is Always and Everywhere an Insulin Phenomenon," "How the Calories In/Calories Out Theory Obscures the Endogeneity of Calories In and Out to Subjective Hunger and Energy" and below, I write directly about the common misinterpretation of the meaning of the calories in/calories out identity. But here let me begin by showing the wrongheadedness of the typical misinterpretation of calories in/calories out by applying the same interpretive angle to another identity: mass in/mass out.
Mass in/mass out is an identity under exactly the same circumstances as calories in/calories out: when there is only a trivial amount of mass-energy conversion going on, as will be true for human beings who are not part of a nuclear explosion. Given that assumption of non-explosivity, the identity for mass in/mass out is even simpler than for calories in/calories out:
weight gain (pounds) = mass in (pounds) - mass out (pounds)
It is simpler because mass in and mass out are in the same units as weight gain: pounds. (Or all three of weight gain, mass in and mass out are in kilograms for those outside the metric-benighted US.) The calories in/calories out identity is complicated by the fact that a pound of body fat corresponds to about 3500 calories, while muscle, glycogen and water in the body all contain a different number of calories per pound. No such complications for the mass in/mass out identity!
Taking the same interpretive angle as is typically used for calories in/calories out, the implications of mass in/mass out for weight loss are as follows. (Warning for those who find it difficult to understand satire: Most of this is bad advice. Please do not take this seriously! If you do, you could harm yourself.) If you think any of these are bad or even dangerous bits of advice, think of how bad the advice might also be from this interpretive angle for calories in/calories out.
To lose weight using the principles of mass in/mass out:
- eat less
- drink less (including drinking less water)
- poop more
- urinate more
- sweat more
There are a few other things that one could do to reduce mass in or increase mass out (bulimics abuse one), but that is a pretty good list.
To me, it is also a familiar list. I was a wrestler in junior high and high school. Like boxers, wrestlers are divided into different weight classes, and it gives a wrestler an advantage to go down to a lower weight. In order to "make weight," wrestlers often do all of the above in the last 24 hours or so before a match or a tournament. Personally, all I did was to not eat or drink for 24 hours before the weigh-in. I didn't need to sweat or spit, and urination and pooping came naturally. The fact that wrestlers use mass in/mass out so successfully shows the truth of its principles.
Warning: If mass in/mass out is a big way you think about weight loss, it could be a warning sign that you have anorexia and bulimia. If you have any suspicious that you might be anorexic or bulimic, you need to get help!
Analogies between Mass In/Mass Out and Calories In/Calories Out
It is not easy for people to understand how the usual interpretation of calories in/calories out can be so wrong. Deep contemplation of mass in/mass out is a potential remedy for this misunderstanding.
Both mass in/mass out and calories in/calories out (interpreted from the usual calories in/calories out angle) are brute force approaches to weight loss. The analogy between mass in/mass out and calories in/calories out is quite good. In both cases, what might seem like the logical advice has some truth to it, but ignores the longer-run regulatory mechanisms at work. For example, with a bit of a lag, drinking water simply causes one to urinate more (and perhaps salivate and sweat a bit more), so over a horizon a few days or a week, drinking water has no effect on weight. Similarly, as I discuss in "Forget Calorie Counting; It's the Insulin Index, Stupid" and "Obesity Is Always and Everywhere an Insulin Phenomenon," more calories in from something that does not cause the body to generate much insulin—say olive oil or nuts—increases metabolic rate and makes you less hungry (so you are likely to eat less of other things). So unless you actively interfere with the regulatory mechanisms, drinking water won't lead to long-run weight gain—and neither will consuming more olive oil or nuts.
Let me give another pair of examples. On the mass in/mass out side, if you eat less, you will poop less, so mass in/mass out doesn't give as powerful an effect from eating less over long horizons as it does over short horizons. There is a limit to how empty one's gastrointestinal tract can be. Over longer horizons, the slower weight-loss process of liquidating glycogen and then the even slower weight-loss process of burning body fat are all one can manage.
On the calories in/calories out side, if you exercise more, you will tend to work up an appetite, and you are also likely to fidget and move around less the rest of the day. That is how the experts explain why you are likely to be disappointed if you are exercising to lose weight. (On the other hand, if you are exercising in order to be healthier, happier and smarter, you are on the right track. For that matter, if you are exercising so you can settle in to your desk chair and get a lot of work done the rest of the day, you might also be on the right track.) Exercising can have some effect on the insulin-sensitivity of muscles, so it can have some long-run weight-loss effect, but naive application of calories in/calories out gives a very bad idea of how much weight loss exercise is likely to lead to in the absence of active interference with the regulatory mechanisms for calories in/calories out.
Both mass in/mass out and calories in/calories out are true identities. But deriving good weight-loss advice from these identities is not so easy. Understanding the regulatory mechanisms is the key. For calories in/calories out, insulin is at the heart of the single most important regulatory mechanism. For mass in/mass out, I leave it as an exercise for the reader to identify the relevant regulatory mechanisms.
Postscript: In addition to being useful for wrestlers and boxers trying to make weight, thinking about mass in/mass out can be very helpful in understanding the short-run fluctuations in weight that can often discourage those on a weight-loss program. By weighing more than once a day, it is easy to convince yourself that over periods of time too short for any significant fat burning or accumulation to take place that your weight can easily vary over a 5 pound range.
For more contrarian discussion of nutrition, obesity and chronic diseases, don't miss:
- Forget Calorie Counting; It's the Insulin Index, Stupid
- Obesity Is Always and Everywhere an Insulin Phenomenon
- Mass In/Mass Out: A Satire of Calories In/Calories Out
- Jason Fung: Dietary Fat is Innocent of the Charges Leveled Against It
- Faye Flam: The Taboo on Dietary Fat is Grounded More in Puritanism than Science
- Sugar as a Slow Poison
- Kearns, Schmidt and Glantz—Sugar Industry and Coronary Heart Disease Research: A Historical Analysis of Internal Industry Documents
- Salt Is Not the Nutritional Evil It Is Made Out to Be
- Confirmation Bias in the Interpretation of New Evidence on Salt
- Whole Milk Is Healthy; Skim Milk Less So
- How the Calories In/Calories Out Theory Obscures the Endogeneity of Calories In and Out to Subjective Hunger and Energy
- Putting the Perspective from Jason Fung's "The Obesity Code" into Practice
- Julia Belluz and Javier Zarracina: Why You'll Be Disappointed If You Are Exercising to Lose Weight, Explained with 60+ Studies (my retitling of the article this links to)
- Meat Is Amazingly Nutritious—But Is It Amazingly Nutritious for Cancer Cells, Too?
- On Fighting Obesity
- Analogies Between Economic Models and the Biology of Obesity
- Diana Kimball: Listening Creates Possibilities
Also see the last section of "Five Books That Have Changed My Life."