Fast Food, Fat Food

Catherine Rampell at Economix posts this interesting chart showing the relationship between the "time the average person in a given country spends eating and that country’s obesity rate (as measured by the percentage of the national population with a body mass index higher than 30)."



Obviously, Obama should require all McDonald's to install more comfortable handicap accessible chairs.

Does anything happend if you just remove the two obvious outliers (USA and Mexico) ?

I don't like the BMI as an indicator of obesity. I personally have a BMI of 29 (not quite 30 but still I was told I was in the overweight range) yet I am hardly overweight. At least I don't think I so; I am undoubtedly under significant bias but my reasoning stems from the following: I am 22, a member of my university's lightweight rowing team, 5'11'', 157 lbs, work out more once a day every day, follow a strict diet and have less than 7% body fat. Yet, my BMI places me in the overweight (just barely not in the obese) category; I would beg to differ.

Likewise my brother has an even high BMI than I, yet he weighs the same and is two inches taller. He is a lightweight rower at his college as well. During my BMI test(?) I was told that because I was an athlete my reading would be skewed upwards. If I understand correctly then, if you workout regularly it will read as obese, and if you don't workout at all it will read as obese. Who then doesn't read as obese?

Let them eat, if you are 157 pounds and 5'11", then your BMI is 22. It's weight in kilos, divided by the square of your length in meters. If your brother weighs the same but is taller, than his BMI must be lower.

@Thomas Paine, your BMI is 22, not 29.

Also, Maoris are quite a small percentage of New Zealanders, and Mexicans *are* a lot fatter than Swedes.

Interesting. It must have been a poorly done test then; we had it done at a health expo. But I specifically remember them saying that athletes do poorly on BMI tests.

The biggest problem I see with this (and many similar) charts is that the correlations are done among groups (in this case, countries) rather than individuals. I'd be much more impressed to see the scatter plot of "time spent eating" vs. BMI for individuals, across nations, to see what correlations there are.

One issue with doing it for individuals is that people are probably terrible at remembering how much time they spend "eating". The only way to do it would be in some sort of study where participants have to monitor their "eating time", but that has all sorts of other problems. That's probably why the country data was given.

@a: There is no correlation if you only look at Europe.

UK is top left en France is bottom left. I suspect the correlation is still well above zero (significance might be a different matter).

@josh: It's Alex though.

But Andy, making the measurement for a group of people has all the problems of making it for an individual, and the additional problems of making sure your sample is representative of the group.

Given the confusion evident in the comments about how to calculate BMI, perhaps the graph is simply a one-dimensional plot of "maladeptness at using metric measurements."

It would correlate well with common stereotypes... Asians at the bottom, because they are good at math; continental Europeans next, because they have used metric longest; former British empire above, because they only switched in the past few decades; Mexico higher because they still use a mix of metric and SAE in commerce; the USA highest as the only major SAE holdout.

Lets also see some unemployment stats for the relevant time period?

How on earth can someone spend 160 minutes eating a day???

I wish economists would stop drawing trend lines on scatter plots. Just stop.

So what? Does this mean that if I spend less time eating I will put up weight?

If preferences for consumption of a particular good also have a characteristic periodicity, then we might observe from this chart that there is some marginal utility frontier both in volume and in time.

From the data presented, it would appear that the most likely causal factor for obesity is fluency in either English or Spanish.

I'm stunned at the culinary efficiency of the French, of all people.

Stan: My wife is Turkish, and eating with her family (especially grandparents) involves a large and indefinite number of courses. By indefinite, I mean that one is never really sure how many more courses are sitting in the kitchen waiting to be brought to the table. These aren't special holiday meals--just standard lunch or dinner with her family.

While eating sit-down breakfast every morning, they talk about what to have for lunch, and then at lunch they talk about what they will have for dinner.

"How on earth can someone spend 160 minutes eating a day???"

I think they eat the small portions slowly, and drink some alcohol and chat a lot. So essentially they let it digest well.

@stan : by eating slowly, having a conversation with the other people at the table and, basically, enjoying the experience.
To some people eating is more than shoving foodstuff in your mouth

On an individual basis BMI *is* nearly worthless. It doesn't tell you anything about a specific person's health, because it doesn't take into account the composition of the weight (ie, how much is fat and how much muscle, or even how much is water on a given day). Body fat percentage is a much more useful indicator of individual health.

On a group level though, population statistics prove that BMI is useful as a screening tool or as a way to identify trends. For example, if you were inducting a large group of people into the military, you may want to more closely examine anyone with a BMI above 20. Take anyone over BMI 20 and measure their body fat. Some of them will just be jocks, but some of them will be slobs. BMI is a quick way of deciding who merits closer inspection.

Or, in looking at a population of people, and you see the BMI going up over the years, you can start to correlate BMI with diabetes or heart disease for example. For any specific person, the correlation may or may not hold up, but for a large group, it does. It's just basic statistics.

Also, it may be true that body fat would be even better for population health studies like this, but body fat takes longer to measure and is not routinely collected data. Doctors always take height and weight though, right? That's one big reason BMI is more prevalent for population studies, I would suggest.

The statement that Athletes "do worse" on BMI is really just a misstatement that is often misunderstood. If you are a certain height and weight, you will have the same BMI whether you are an athlete or not, since it's just a ratio of the two measurement. Some athletes do have BMI's that look bad on paper because they are heavier for their height than some non-athletes of the same height, but the BMI is different because the weights are different, not just because one is an athlete and the other isn't. Any person with eyes can tell a rower/runner/wrestler person with a BMI of 29 has a healthier bodyfat than a couch potato with the same BMI (all other things being equal).

Come on people, learn to see the forest from the trees. One would think that the readers of an economics blog would understand how statistics work.

BMI is not a very good indicator at an individual level. However, when looking at an entire population, it's a good statistical tool.

Every country in that list has its own set of muscular athletes. Unless you can claim that 30% of Americans are part of that group, while only a quarter of a percent of Europeans are, the chart is still significant.

"BMI is not a very good indicator at an individual level. However, when looking at an entire population, it's a good statistical tool."

Only assuming everyone has the same body type, which works fine for single or similar ethnic groups, but poorly when comparing Japanese to Europeans to Mexicans.

I'm with Mr. Paine, 'cuz last time I was out at the mall I just couldn't believe how fit everyone had become.

To Dave:
No, BMI is not bullshit, it is a calculation based on averages. If you are a freaky short guy who can bench press himself that doesn't have any bearing on BMI. Based on averages you are overweight. Whether that weight is fat or muscle not has nothing to do with a BMI test.

If you have less time to eat, you probably eat more pre-prepared foods. I think this might have more to do with ingredients than time. They should consider the percentage of whole ingredients used in each country against the obesity factor.

As a side note, perhaps they could consider the percentage of the diet comprised of corn-based ingredients...

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