I see that I do have some new readers. Gene Callahan says
Your “ridiculous” answer on obesity seems obviously correct to me — maybe insufficient, but fine as far as it goes — and the answer to the “puzzle” also obvious — adjust calories in and calories out until you are at a stable weight that you like. What is “ridiculous” about that?
The first issue is that saying one ate too much or too exercised too little is a non-answer. It simply takes the equation of motion and applies a normative frame to it.
I could say that rocks fall because they have too little resistance to the propensity to fall. This is a non-answer. It simply takes the analytical notion that resistance impedes motion and the observation that things fall and applies a normative frame to it.
How would we know if the resistance is too little? Because the rock fell. How would we know if the resistance is enough? Because the rock did not fall.
This tells us little, except that you are aware that things fall.
What we would like is something that takes parameter values and then tell us what result we should expect.
Now, the second part of Gene comment is slouching towards a model. He words it as instructions but if we recast it as a general framework we get something like this.
- Weight change is the residual of the choice variables calories-in and calories-out
- When people are unsatisfied with their weight the adjust one or both of these variables to make the residual positive or negative.
- When they are satisfied with their weight they adjust one or both of these variables to make the residual zero.
This has the virtue of being the beginning of a model. It has the vice of being at odds with the facts.
Lets set aside for a moment the issue how would we know if people are satisfied with their weight because I think it is too emotionally loaded. Instead, lets investigate the dynamics of this model with exogenous shocks.
First, imagine a young teenager who is temporarily at some stable weight and so presumably is satisfied and has chosen a residual of zero. Then the teenager hits a growth spurt. Under our model the teenager’s weight does not change.
He or she will grow taller but will not grow heavier. And, so BMI will fall and at the square of height change. If at this new BMI the teenager is unsatisfied with his or her weight then he or she may alter calories-in and calories-out to achieve a new weight, but in the absence of such conscious alteration weight will be fixed as height extends and so BMI will fall.
Does this appear to be what’s going on? Are teenagers accidently getting thinner as they grow taller and then moving to correct that?
Second, imagine a woman who gets pregnant. Again, under our model her weight will not change. Thus in the absence of conscious alteration of her caloric balance her core body will lose at least as much weight as the fetus and placenta gain. Indeed, she will lose more because the fetus and the placenta produce metabolic waste.
Now she may become unsatisfied with the loss of core body weight and move to alter caloric balance but in the absence of such unsatisfaction she will lose core body weight. Moreover, once the fetus and placenta exit the residual will exogenously rise and her core weight will move back to its original amount.
Does this seem at all like the patterns we observe?
Not to give away the show, but one might suspect that there is a mechanism which works to adjust either calories-in or calories-out in response to growth spurts and pregnancy. Our questions might be, does such a mechanism exist? How does operate? Is it present even when these events are not occurring?
26 comments
Comments feed for this article
Thursday ~ December 22nd, 2011 at 12:37 pm
Kevin Drum
I’m mystified by this endless beating around the bush. I’m pretty sure you have a very simple point to make here. Why not just tell us what it is?
Thursday ~ December 22nd, 2011 at 1:49 pm
Wonks Anonymous
Hormones.
Thursday ~ December 22nd, 2011 at 1:11 pm
Corey Mutter
As a 300-lb aspiring rationalist, let me cut straight to the interesting question:
What is making it difficult for people to maintain healthy weights?
Everyone seems to assume that the underlying issue is just a generalized lack of willpower. I know this to be untrue in my case, and we see lots of fatties that hold down jobs, etc. In my case I just eat more calories than I use, and if I want to eat less, it takes about the same amount of willpower that it would take for a fraternity to quit drinking.
So instead of asking “why do all these fatties have so little willpower?”, the interesting question is “why does eating the right amount require more willpower than fatties have?”
In my own case I believe it’s multi-pronged: easy availability of “superstimulus” food, issues from growing up poor, and stress.
Thursday ~ December 22nd, 2011 at 2:52 pm
Sister Y
Indeed, I remember reading that variation in willpower (marshmallow experiment, etc.) explains only a small fraction of variation in excess body weight, but can’t find the cite. Baumeister, I think?
Friday ~ December 23rd, 2011 at 11:55 am
jpersonna
Do you believe in evolution?
Thursday ~ December 22nd, 2011 at 1:20 pm
Mike Cramer (@mikewebkist)
And add to that the fact that although some people are heavier than others, most end up at a stable weight fairly quickly (in absence of dieting.) This implies that although people may be unhappy with their weight, their bodies are actually very good at maintaining a zero residual (as Karl puts it.)
Thursday ~ December 22nd, 2011 at 1:56 pm
Chip Smith
Karl,
Are you suggesting that peoples’ pituitary glands are malfunctioning en masse? Perhaps because of some new environmental trigger?
Thursday ~ December 22nd, 2011 at 5:02 pm
Annelid Gustator
That is, indeed, very nearly what he suggests. Why he calls that a non-answer I’ll never know.
Thursday ~ December 22nd, 2011 at 2:28 pm
Matt
“Not to give away the show, but one might suspect that there is a mechanism which works to adjust either calories-in or calories-out in response to growth spurts and pregnancy. ” Answer: hormones
Now if the point of all these blog posts are to identify a “smoking gun” that has caused the girth in the US to rise over the past 30 years I would suggest corn. Corn yields have increased consistently since then end of WWII and the energy source it produces is now in the majority of the food we eat. This is also being fed to the food we eat even when its not the optimal energy source for such food(beef, pork, chicken).
Secondly, it is the job of food scientists to “enhance” food so it triggers our pleasure centers yet has fleeting satiation. Yes, food is a drug. Now it is harder to say no to certain foods and more likely you eat more. We have also seen our portion sizes increase as we find it harder and harder to feel satiated and we are economically able to reach satiation. Of course there are other contributors, and calories in vs. calories out is a poor indicator of health/weight. Yes, the body does adapt and attempt to stay at “zero.” (again hormones) The type of calories we consume also play a huge role in our health and energy levels. Small molecules, vitamins, and nutrients are in different concentrations and accessibility levels in different food types.
Another possible example is amount of meat (mostly corn fed) we eat. We now have a diet where 50% of our calories comes from meat, opposed to 5% pre-world war II. The quality of meat is driven by the big consumers such as McDonalds. Such meat is corn fed and pumped with hormones/antibiotics. Even if you avoid fast food the majority of beef produced is poor quality and the most affordable.
All this evidenced can and mostly is waived away as circumstantial but it is much more plausible than a gene or a ubiquitous chemical that has popped up in the past 20 years. Generally mutations to a population are slow moving, especially in a highly connected population such as the US. If it’s a chemical, it must be in our food which suggests again corn (fertilizer, herbicide, new protein produced by GMO mutation. I find each of those unlikely.
Personally, if I want to lose weight I increase my bike riding, maintain or slightly increase by calories, drink more water, cut calories consumed through alcohol, reduce calories consumed trough meat to about 0-3% (not including egg whites), and increase calories consumed through vegetables and fruit, cut out as much simple/refined sugar as possible. So it appears my pituitary gland is functioning fine and allowing me to lose weight.
There seems to be a common theme to your posts that involve science (climate change and obesity). Over complicate the problem to the point of apathy towards a solution with the goal of maintaining the statuesque.
Thursday ~ December 22nd, 2011 at 2:36 pm
jimmyh
To be fair, the “calorie in – calorie out” view makes some testable predictions (conservation of energy), but it is horribly incomplete.
It’s not even a question of will power, since most “not fat” people can eat as much as they want.
The rest of the question is “how does the system that regulates input-output work, and what knobs can we tweak?”
Seth Roberts has taken a huge chunk out of the problem with his self experimentation.
http://sethroberts.net/about/whatmakesfoodfattening.pdf
Thursday ~ December 22nd, 2011 at 2:41 pm
Chris Stucchio
Pregnant women have to eat more to maintain a healthy weight. When they don’t increase their food consumption, they do indeed lose core weight. The net result is often miscarriage or other health problems. This is a very serious problem in India.
When women don’t reduce their consumption of calories after pregnancy, they tend to become fat. This is a common occurrence.
Also, Karl’s example of a teenager’s BMI going down as they enter a growth spurt happens frequently. Typically a teenager becomes a fat and then has a growth spurt, which reduces their BMI to normal weight. When children don’t eat in excess of maintenance, this typically prevents the growth spurt from occurring (fun fact: North Koreans are 4″ shorter than South Koreans).
Thursday ~ December 22nd, 2011 at 2:50 pm
Chris Stucchio
Forgot to mention, adjustment is even easier than Karl Smith claims.
If an adult of constant height wants to achieve a given bodyweight, they need to engage in one step: set calories in equal to the maintenance level of the bodyweight they want. Nothing else is required.
http://crazybear.posterous.com/the-calories-incalories-out-model-explains-we
Thursday ~ December 22nd, 2011 at 3:35 pm
Mike Cramer (@mikewebkist)
This suffers from the same problem Karl identifies: that some people weigh more but don’t expand unbounded is an observation which those equations may capture perfectly but don’t explain how a 250lb man manages to maintain a nearly perfect calories-in=calories-out while someone else does the same at 190lbs and someone else at 150lbs.
Calories-in=calories-out is a true observation but has little to tell us about why people get fat.
Thursday ~ December 22nd, 2011 at 5:54 pm
Chris Stucchio
Mike, the calculations I provide shows why everyone who eats a constant amount of calories maintains a perfect balance of calories in/calories out – their bodyweight will increase or decrease until the perfect balance is achieved.
I.e., people don’t adjust calories to agree with some random bodyweight, their bodyweight adjusts until calories out == calories in.
It’s true that it doesn’t explain why they choose to eat 2000 cals or 4000 cals. The best way to find that out is to ask. If you ask me, I’ll explain that I eat 4000 cals/day currently (about 500lb above maintenance) because I’m bulking. If you asked me on thanksgiving, I’d say I ate 8000 cals because thanksgiving dinner was tasty.
You want a scientific theory of people’s choices and motivations? Ok, cals in/cals out isn’t it. Cals in/cals out is merely a theory of what happens after they make those choices.
Similarly, Newtonian mechanics is a theory of how cannonballs fly, not why people shoot cannons.
Thursday ~ December 22nd, 2011 at 2:50 pm
John
I’ll just comment anecdotally, i.e., personally.
Everyone in my immediate family is or has been obese. The exception is my next-younger sister, an MD, who was obese most of her life but lost weight over about 9 years due to an unknown intestinal obstruction that nearly starved her to death – she spent a month in the hospital when it was finally diagnosed, and it still, 2 years later, has not been resolved. She now struggles to be able to eat enough just to survive – meal supplement drinks are a large part of her daily diet.
My older sister had a gastric bypass and lost over 100 pounds, most of which she’s since regained.
My mother was well over 300 pounds most of her life. As was my father – he and several of his siblings were morbidly obese, though others were normal weight or below, despite all having had similar eating habits. One of my father’s uncles was buried in a piano case.
I work out almost daily, and eat, in my opinion, very little. I’m not a lazy person, and I myself have a PhD. I take medications that rob me of energy, but I’d have that problem even without those medications. My metabolism is just naturally low – whether genetically so or not, I can’t say, nor have my many doctors (among them endocrinologists).
I have to eat a certain minimum amount or I simply don’t have enough energy to keep myself awake, let alone get through a normal day. I.e., what I eat isn’t converted to energy like it is for a more normal person – it’s prone to store as fat instead. But my weight, over the past few decades, has been stable – at a bit over 300 pounds.
I have never in my life met a single person who wants to be overweight. And I doubt I ever will.
But I can also tell you, as an African-American, that although I’ve personally experienced racial discrimination many times in my life, it’s never been as bad as what I’ve see experienced by normal weight people against those who are “obese,” on a regular basis.
Alas, bigotry takes many forms.
Friday ~ December 23rd, 2011 at 12:57 am
starwars
This commenteriat as a group needs to read Good Calories, Bad Calories by Gary Taubes. There is a lot of evidence that the calories in = calories out paradigm that currently dominates nutrition is completely wrong. Bodies process different macronutrients in different ways.
Eat less carbohydrates and more protein and fat and you will lose weight. Fat people should never eat anything grain or legume based, anything with sugar in it, and probably not even fruit. Meat and vegetables fatties. Naturally skinny people have a lot more leeway and genetics plays a huge role in your morphology.
Also, I am with Kevin. I read this blog because I think Karl has some very interesting economic insights but his writing style is just obnoxious. It’s like he is talking to a girl at a bar, stringing on her on with vague half statements, playing the mysterious stranger, never saying what he really means. Even when he does purportedly explicitly state his views he writes in snippets that require incredible intellectual leaps or a knowledge of his canon.
This series on nutrition has been pretty bad but he was at his absolute worst in his series on depression. The pretension was just painful. “I’m writing a post about something that I think no one should ever talk about in order to point out that I think no one should ever talk about this. Because I am a serious intellectual figure and the blatant hypocrisy of this act will be overwhelmed by the adulation of my many adherents.” Give me a break (all you accomplished was having people ask what the hell you were talking about and then reading up on the issue that you explicitly wanted nobody to know or talk about!).
He also knows nothing about science. If you are reading this blog and forming opinions about questions of scientific fact based upon it you are either naive or an idiot.
Karl is basically the anti-Orwell when it comes to writing. Everything is wink wink or euphemism instead of a clear and coherent statement of what he would (supposedly) like to communicate.
He is also a terrible hypocrite. He claims to be a pessimist because of the theoretical (though certainly implied by most current models) heat death of the universe 10^100 years from now but is the most optimistic economic prognosticator I have encountered. Who gives a shit about the heat death of the universe? It would be shocking if a single human being ever suffered from its occurrence. We are just animals, smart animals, but animals who may and probably will go extinct on a timeline a tiny fraction than your purported reason for pessimism.
I mean I guess he is who he is, but to me it almost seems like he is playing to type: the hyper-rational, brooding, sociopath without any regard to what he actually thinks or feels.
Basically, I think he is good at his day job but usually horribly off base whenever he ventures into a realm outside his area of expertise.
Friday ~ December 23rd, 2011 at 8:32 pm
John
“Meat and vegetables fatties”?
Fatties? That’s the kind of bigotry to which I was referring, starwars. Thanks for demonstrating, with all due respect.
“Eat less carbohydrates and more protein and fat and you will lose weight.”
Not necessarily.
Let me ask you, what’s the difference among carbohydrates, fats, and proteins in metabolic terms? The answer goes to my original comment about energy.
And yes, I am diabetic, and yes, I know the dietary drill, and having a PhD in a scientific discipline, it’s my inclination to research such things.
Which means, no new information coming from you here.
As the saying goes, “In theory, there’s no difference between theory and practice. In practice, there is.”
Sheesh.
Friday ~ December 23rd, 2011 at 11:37 pm
starwars
Of course you have diabetes. Virtually every 300 pounder outside of the NFL is diabetic.
Carbohydrates are fundamentally different because they have a profound effect on the release of insulin (they highly promote it). The full mechanism is too complicated to explain in a comment at a blog, but the basic idea is the more carbohydrates you eat, the more basal insulin you have in your blood, (insulin has a profound effect on the way calories are used) the more fat you deposit, and the more likely you are to develop type II diabetes. Essentially, eating a lot of carbohydrates disrupts an aspect of your bodies homeostasis (regulation of blood sugar and fat deposition).
It is no coincidence that the obesity epidemic in the United States has been mirrored by a massive increase in the incidence of type II diabetes. Again, read Taubes for the full explanation.
As for your moral umbrage at my perceived prejudice, give me a break. You are fat because: a) you have a low basal metabolic rate (tough break, sorry) but also b) you either don’t know or don’t care about the proper way to regulate your weight. You need to minimize your consumption of carbohydrates and lift heavy weights to add muscle mass (thereby raising your basal metabolic rate). Being fat is either tragic (you’re ignorant of the way to make yourself not fat, true of very many Americans) or evidence of an addiction like alcoholism (you care more about eating then about self-presentation or your health).
Calling someone a fatty or disdaining fat people is completely different from being prejudiced against someone for something they can’t control (i.e. race). You ultimately can control your weight, you just either don’t know how to or choose not to. Plus being a fat person imposes all kinds of costs on other people (higher healthcare costs, discomfort of being in a confined space with a fat person) that the kind of prejudice that enlightened society abhors (e.g. homophobia). The fact that my neighbor is gay has no negative impact on my physical well being but you being fat does (higher healthcare spending, sitting next to you on a plane would be horrible, etc.)
Friday ~ December 23rd, 2011 at 11:58 am
jpersonna
As implied by my above question, I think this is a problem for evolutionary psychologists, and not economists. We have a set of food drives based on an ancient and vanished profile of food availability.
That, and it was probably better for group survival to have a variety of body types in play.
I’m skinny with a high desire for saturated fats because that was at least worth a try in old Iceland/Denmark.
Friday ~ December 23rd, 2011 at 12:12 pm
Gepap
Calories in calories out is correct. Burning more calories than you take is the reason why your body will convert fatty deposits into something else, and being obese is about having large fatty deposits. That is the whole POINT of fatty deposits in the first place, to convert excess macronutrients not needed at the point of ingestion into a form that can be stored for later use given the possiblity (likelyhood) of future periods of scarcity.
The issue is that each body differs in how effectively/efficiently it processes calories in from different sources and how it burns calories. Thus a one-size fits all approach will fail.
That fact does not invalidate the correctness of the initial statement on calories though.
Friday ~ December 23rd, 2011 at 1:19 pm
Noumenon
I don’t see it as beat-around-the-bushy, he’s just persuading on one thing at a time and explaining how he thinks about the problem so that you can come to the same conclusion yourself, instead of just giving his end point. Don’t hate on the Karl!
Friday ~ December 23rd, 2011 at 2:02 pm
Cameron
For the purposes of the model, it’s irrelevant if calories in/calories out is ACTUALLY what is happening. What matters is if that model has predictive power. If we consume more calories as an ancillary part of our growing, temporal precedence may not even matter.
Friday ~ December 23rd, 2011 at 2:28 pm
Gene Callahan
Three quick points:
1) The growing child and pregnant woman examples are ridiculous. Obviously, in that I was formulating a “model,” the model was meant to apply to a non-pregnant, fully grown adult.
2) The rock example does not make the point you want it to. Merely to formulate the idea of “resistance” is a major step forward. This seems a “non-answer” to you only because you take that idea for granted. Similarly with calories: before 200 years ago, no one could have even conceived of the problem in terms of calories. So, one might want *more* of an answer, but that is already a non-ridiculous answer.
3) A model is not an explanation. It simply duplicates some aspect of the phenomenon under investigation in a simplified fashion. That such a simplification explains nothing ought to be obvious.
More anon. Prime rib to cook now.
Thursday ~ December 29th, 2011 at 12:31 pm
The Epidemic of Obesity: Non-Answers and Attempted Explanations « fliberdigibek
[...] been sufficiently interesting to be worth commenting on were it not for one particular claim and a follow up post. The claim is that “The baseline assumption… that obesity results from people eating [...]
Monday ~ January 2nd, 2012 at 11:58 pm
Dean
There’s an awful lot of bad physics in obesity writing, and even more bad biology. The actual equation is “assuming a spherical cow” calories-in/kg = calories-out/kg. “calories-in = calories-out” assumes that metabolic rate per kg is proportional to 1/total-weight. Now it is roughly true that obese people have a lower per-kg metabolic rate than lean people, but there’s no way that this relationship is linear.
Gary Taubes seems to be on track with his “isocaloric is not isometabolic” hobbyhorse, but it’s a lot more complicated than that. There are well documented differences in sensory/motivational cues and their linkages to behavior for hunger and satiety between obese and lean people.
And to add my own theoretical contribution, there may be differences in brain glucose demand between different kinds of mental tasks. For example, there were just as many couch potatoes in the 1960′s and ’70s, but they were passively watching TV, not playing video games with intense information processing and decision-making demands, leading to disregulation of the blood glucose and insulin demands of the brain vs somatic tissue. Enough glucose to satisfy the brain is too much for the body, so the body disposes of the excess in fat cells.
Tuesday ~ January 3rd, 2012 at 2:52 pm
Gene Callahan
“For example, there were just as many couch potatoes in the 1960′s and ’70s,”
And we determine this by the scientific procedure of sheer assertion.