Иван А. Султаник, Ph.D.

Despite awkwardness caused by his recent rants on the topics of modern cooking techniques and more recently fandom, Alton Brown is still one of my favorite sources of culinary quotes. One of which, related to nutrition, is

There are no "bad foods", only bad food habits.

In keeping with my recent posts' unintentional gastronomic theme [1,2], I am going to dedicate this post to debunking a myth related to the above quote. I claim that there is no bad time to eat, only bad eating habits. Specifically, I'd like to dispell the common misconception that the time of one's meal alone can affect weight gain.

I recall hearing a story on NPR a year or two ago about a study which specifically tried to test the claim that eating late at night is unhealthy. The study concluded that there was absolutely no correlation between the proximity of mealtime to sleep and weight gain, other than the fact that people tend to choose to eat more unhealthy foods late at night. I can’t seem to find a reference to that study, however, so I am going to have to do some research myself. Right. Lets get stuck in.

The majority of our food is actually digested during sleep, so the common argument that “eating late at night is bad because our metabolism [slows or shuts down] during sleep” is incorrect. With that said, there is a correlation between night eating, low self-esteem, reduced daytime hunger, and weight loss among people who are already obese or prone to obesity, however, this correlation does not necessarily imply causation (i.e., the act of eating a late meal does not necessarily provoke these conditions). It may simply be the case that the types of foods that people prefer to eat late at night are less healthy. There is still much debate on the subject, however, many scientists agree that meal frequency, as opposed to time, is one of the best predictors for weight gain. For example, the time between meals is highly correlated to one’s waist size. This makes some intuitive sense, since eating more, smaller meals will help regulate insulin levels, and spikes in insulin levels (which can be caused by large meals and/or large gaps in time between meals) have been linked to weight gain.

A newer study followed the eating and sleeping patterns of 52 subjects over one week. They found a correlation between “late sleepers” (i.e., people who go to sleep late and wake up late) and high body mass index, and that eating after 8pm was associated with higher body mass index. A relatively recent New York Times article summarizing the results of the study makes the further claim that eating late at night leads to weight gain, however, I disagree with that claim on the grounds that correlation does not imply causation. In fact, the original study noted:

Late sleepers consumed more calories at dinner and after 8:00 PM, had higher fast food, full-calorie soda and lower fruit and vegetable consumption.

Therefore, I think the results of the study can be interpreted to mean that there is a correlation between eating/sleeping late and a poor diet.

Furthermore back in 2006, the same research team conducted a study on monkeys in which they were fed a diet similar to the average (i.e., high-fat) diet common in the USA. The only variable was the time of day that the monkeys were fed. With all else remaining constant, the researchers found no correlation between weight gain and time of feeding.

It was really interesting to see that the monkeys who ate most of their food at night were no more likely to gain weight than monkeys who rarely ate at night. This suggests that calories cause weight gain no matter when you eat them.

While I’m on a roll here, let me quickly dispel yet another myth. I know many people that adhere to the strict “calorie-in/calorie-out” nutritional theory. This seems particularly popular among mathy/engineering types. The idea is that if your body burns fewer calories than what it takes in through food then it will gain weight. This theory, in general, is fallacious. The body doesn’t necessarily consume all of the calories of the food we stick down our throats. The time between meals will, in effect, affect the way one’s body “decides” to digest the food. Furthermore, as this study and others like it suggest, not all types of calorie sources are equal when it comes to how the body processes them!

In conclusion, if you’re overweight, it’s not necessarily legitimate to blame your late-night eating schedule. You can’t even blame your high calorie diet (only the types of calories you choose to eat).

Is it cheaper to eat fast food than to cook a meal from scratch? Answering such a question is difficult, given that costs will vary greatly from country to country. Why? Well, raw commodity prices are very volatile due to varying government subsidies, differences in climate, extreme climatic events, supply chains, &c.

The supermarket industry in the US is extremely competitive. SuperValu, for example, is a giant corporation that owns many supermarket chains. They are lucky to eek away a 1.5% profit margin. (In other words, at most 1.5% of their gross income is a profit.) That means they could lower their prices at most ~1.5% without taking a loss. Bulk sellers like Costco and even the giant Wal-Mart are lucky to reach 3%. Successful fast food restaurants like McDonalds, on the other hand, easily reach a profit margin of 20%. That means, in effect, McDonalds could reduce their prices by ~20% and still stay afloat.

Why is this? One major reason is that companies like McDonalds can and do have complete vertical integration of their supply chains: McDonalds raises their own cattle, grows their own potatoes, transports their own raw ingredients, and largely owns the real estate of their restaurants. In fact, McDonalds even makes a profit off of leasing their real estate to McDonalds franchises. That flexibility is partially one reason why a Big Mac will be worth the equivalent of US\$10 in Brazil while the same Big Mac will be worth US\$1.50 in Croatia. Supermarkets don’t really have much opportunity for vertical integration unless they actually buy and operate their farms and suppliers.

So, is eating fast food really cheaper? As I mentioned in my previous blog entry about food deserts, in the US there is a definitive link between poverty, obesity, and lack of proximity to a supermarket. There was also a study in the UK that discovered a correlation between the density of fast food restaurants and poverty:

Statistically significant positive associations were found between neighborhood deprivation [i.e., poverty] and the mean number of McDonald’s outlets per 1000 people for Scotland ($p < 0.001$), England ($p < 0.001$), and both countries combined ($p < 0.001$). These associations were broadly linear with greater mean numbers of outlets per 1000 people occurring as deprivation levels increased.

Let’s have some fun now and look at the Consumer Price Index (CPI), which estimates average expenditures for various goods over a month. The current CPI in the US for food and beverages is \$227.5 (meaning that the average consumer spends \$227.5 per month on food and beverages). Now let’s assume that the cost of non-fast-food is cheaper than eating fast food and proceed with a proof by contradiction. Under this assumption, the CPI of \$227.5 is obviously a lower bound on the amount one would spend if one only ate fast food (since the CPI includes all types of food-related expenditures). This equates to about \$8 per day. In 2008, the average price of a Big Mac in the US was \$3.57, and it is certainly possible for one to subsist off of two Big Macs per day. That’s especially true since a Big Mac is one of the more expensive items on the McDonalds menu. A McDouble, for example, costs only \$1. This is a contradiction, i.e., we have shown that it is in fact possible to live off of less than \$8 a day of fast food, thus breaking the lower bound and invalidating our assumption that eating non-fast-food is cheaper than eating fast food.∎

This suggests that it is at least plausible that eating fast food could be cheaper than grocery shopping in the US.

What is a food desert? That’s “desert” as in “Sahara,” not the sweet thing you eat at the end of a meal. According to Wikipedia, it's

any area in the industrialised world where healthy, affordable food is difficult to obtain,

specifically associated with low income. There is a good amount of debate about whether such things even exist. The problem, as I see it, is that this definition is very subjective: One can always have access to high quality or nutritional food if one is willing to spend enough time to travel to it. If a person lives a couple miles away from a grocery store but has "access" via expensive (to them) public transport, does that constitute "access"? Technically, of course, yes. But what I really think the question should be:

Is there any statistical correlation between proximity to full-service grocery stores, obesity, and poverty?

I think the answer to that is "yes". Answering why is a much more difficult (and perhaps open) question. Read on to hear my reasoning.

One of the differences between modern US English (hereafter referred to as "American English") and British English is the way in which we pronounce foreign words, particularly those of French origin and/or related to food. For example, Americans…

• drop the "h" on "herb" and "Beethoven";
• rhyme "fillet" and "valet" with "parlay" as opposed to "skillet"; and
• pronounce foods like paella as /paɪˈeɪə/ (approximating a Castilian or Mexican accent), whereas the British pronounce it as /pʌɪˈɛlə/.

In general, the British seem to pronounce foreign/loan words as they would be phonetically pronounced if they were English, whereas Americans tend to approximate the original pronunciation.  I've heard some people claim that this trend is due to the melting pot nature of America, and others claim that the French pronunciation, in particular, is due to America's very close relations with France during its infancy.  This latter hypothesis, however, seems to be contradicted by the following:

Avoid the habit of employing French words in English conversation; it is in extremely bad taste to be always employing such expressions as ci-devant, soi-disant, en masse, couleur de rose, etc. Do not salute your acquaintances with bon jour, nor reply to every proposition, volontiers. In speaking of French cities and towns, it is a mark of refinement in education to pronounce them rigidly according to English rules of speech. Mr. Fox, the best French scholar, and one of the best bred men in England, always sounded the x in Bourdeaux, and the s in Calais, and on all occasions pronounced such names just as they are written.

I wondered: At what point did the USA drop the apparent British convention of pronouncing foreign words as they are spelled?

I asked this question on English.sx, to little fanfare; most people—including Peter Shor!!!1—had trouble accepting that this phenomena even exists.  Therefore, I extend my question to the Blogosphere!

I did some more digging, and it is interesting to note that there seems to be a trend in "upper-class" (U) English to substitute words that have an obvious counterpart in French with words that are either of Germanic origin or those that do not have a direct equivalent in modern French.  For example, in U English:

• scent is preferred over perfume;
• looking glass is preferable to mirror;
• false teeth is preferable to dentures;
• graveyard > cemetery;
• napkin > serviette;
• lavatory > toilet;
• drawing-room > lounge;
• bus > coach;
• stay > corset;
• jam > preserve;
• lunch > dinner (for a midday meal); and
• what? > pardon?

This is admittedly a stretch, but perhaps there is some connection between the US's lack (and some might say derision) of a noble class and its preference toward non-U/French pronunciation?

I think the claim that "no two snowflakes are alike" is fairly common. The idea is that there are so many possible configurations of snow crystals that it is improbable that any two flakes sitting next to each other would have the same configuration. I wanted to know: Is there any truth to this claim?

Kenneth Libbrecht, a physics professor at Caltech, thinks so, and makes the following argument:

Now when you look at a complex snow crystal, you can often pick out a hundred separate features if you look closely.

He goes on to explain that there are $10^{158}$ different configurations of those features. That's a 1 followed by 158 zeros, which is about $10^{70}$ times larger than the total number of atoms in the universe. Dr. Libbrecht concludes

Thus the number of ways to make a complex snow crystal is absolutely huge. And thus it's unlikely that any two complex snow crystals, out of all those made over the entire history of the planet, have ever looked completely alike.

Being the skeptic that I am, I decided to rigorously investigate the true probability of two snowflakes having possessed the same configuration over the entire history of the Earth. Read on to find out.

Last year I made a rather esoteric joke about a supposed phenomena called the "Ballmer Peak" that was popularized by a web comic. The idea is that alcohol, at low doses, can actually increase the productivity of a computer programmer.  The original claim was obviously in jest since, among other reasons, Randall Munroe (the web comic's author) claimed that this peak occurs at exactly 0.1337% blood alcohol content. This got me thinking: Could there be any truth to this claim? Read on to find out; the results may surprise you.

Political scientist Ed Burmila—sole remaining contributor to one of my favorite weblogs on the Internets, Gin and Tacos—just asked his readership,

What brought you here initially? Was I suggested by one of your friends? Did you arrive from a link on a different site – especially Crooks & Liars? Random internet search? Internet search specifically for gin and/or tacos? Saw a sticker on someone's car? Wrote three words in the search bar, hit ctrl-Enter, and hoped for the best?

I have been reading Gin and Tacos for almost its entire, decade-long existence. I didn't mean for that to sound so hipsterish, but there's not much other way to put it. I remember when I first stumbled on the site having entered "Robert Burnett" in my search bar, back in the days when G&T.com had more in common with its name than simply being awesome. I, like Ed, was a poor graduate student at the time, and I too had discovered the siren call of Sir Robert Burnett's London Dry Gin. (Perhaps I inherited this penchant from my advisor.) I'm not sure about G&T.com's Robert Burnett fan fiction, though.

I was, however, intrigued by Ed's, et al., historical sleuthing in trying to track down the truth behind the real Robert Burnett. Unfortunately, here is all they were able to conclude:

• Robert Burnett Jr. and Sir Robert Burnett were active in politics, however neither were mayor of London.
• The Burnett family was very active in military recruitment.
• Most importantly, that the Burnett family dealt in liquors.
• Finally, Sir Robert Burnett had a pretty damn nice estate.

Unfortunately, none of my research resulted in specific reference to gin. This is primarily due to the fact that the only available source to me was the Times of London, although there might have been advertisements for Burnett’s Gin in the Times, they did not come through on the search. Someone with more experience in alcohol oriented history could possibly do better.

I was no expert in history, however, like most Ph.D. students, I was a world renowned expert in procrastination. I therefore took on the task. Read on to see my (now six year old) results.

Is it true that everyone on earth is separated by at most six degrees? There's plenty of empirical evidence to support this claim already, so I am going to take a different, more theoretical approach.

Read on to see my results.

So, I’ve gotten rid of MediaWiki and switched back to Drupal (now in version 7). The old version of this site is still available here. I’ll be posting another blog entry in the coming days explaining why I’ve chosen to abandon MediaWiki. I’ve already migrated most of the content from my old website, but there is still some to go. The address for my old RSS feed still works, however, Google Reader seems to be ordering the entries non-chronologically and I am not sure why.

I’m currently teaching a class and receive all of the homework submissions digitally (in the form of PDFs). Printing out the submissions seems like a waste, so I devised a workflow for efficiently grading the assignments digitally by annotating the PDFs. My method relies solely on free, open-source tools.

Here’s the general process:

1. Import the PDF into GIMP. GIMP will automatically create one layer of the image for each page of the PDF.
2. Add an additional transparent layer on top of each page layer.
3. Use the transparent layer to make grading annotations on the underlying page. One can progress through the pages simply by hiding the upper layers.
4. Save the image as an XCF (i.e., GIMP format) file.
5. Use my gimplayers2pngs script (see below) to export the layers of the XCF file into independent PNG image files.
6. Use the composite function of ImageMagick to overlay the annotation layers with the underlying page layers, converting to an output PDF.

Below is the code for my xcflayers2pngs script. It is a Scheme Script-Fu script embedded in a Bash script that exports each layer of the XCF to a PNG file.

#!/bin/bash
{
cat < i 0)
        (set! bottom-to-top (append bottom-to-top (cons (aref all-layers (- i 1)) '())))
        (set! i (- i 1))
        )
      (reverse bottom-to-top)
      )
    )

(define (format-number base-string n min-length)
  (let* (
	 (s (string-append base-string (number->string n)))
	 )
    (if (< (string-length s) min-length)
	(format-number (string-append base-string "0") n min-length)
	s)))

(define (get-full-name outfile i)
  (string-append outfile (format-number "" i 4) ".png")
  )

(define (save-layers image layers outfile layer)
  (let* (
	 (name (get-full-name outfile layer))
	 )
    (file-png-save RUN-NONINTERACTIVE image (car layers) name name 0 9 1 1 1 1 1)
    (if (> (length layers) 1)
	(save-layers image (cdr layers) outfile (+ layer 1)))
    ))

(define (convert-xcf-to-png filename outfile)
  (let* (
	 (image (car (gimp-file-load RUN-NONINTERACTIVE filename filename)))
	 (layers (get-all-layers image))
	 )
    (save-layers image layers outfile 0)
    (gimp-image-delete image)
    )
  )

(gimp-message-set-handler 1) ; Send all of the messages to STDOUT
EOF

echo "(convert-xcf-to-png \"$1\" \"$2\")"

echo "(gimp-quit 0)"
} | gimp -i -b -

Running xcflayers2pngs file.xcf output will create output0000.png, output0001.png, output0002.png, ..., one for each layer of file.xcf. Each even-numbered PNG file will correspond to an annotation layer, while each odd PNG file will correspond to a page of the submission. We can then zip the even pages with their associated odd pages using the following ImageMagick trickery:

convert output???[13579].png null: output???[02468].png -layers composite output.pdf

We can automate this process by creating a Makefile rule to convert a graded assignment in the form of an XCF into a PDF:

%.pdf : %.xcf
        rm -f $**.png
        ./xcflayers2pngs $< $*
        convert $*???[13579].png null: $*???[02468].png -layers composite $@
        rm -f $**.png