Obesity and food palatability

▼ I've been doing a lot of reading and Youtube watching about nutrition the past year or so. So I've seen all the scary numbers about the increasing obesity levels in the United States (and elsewhere) numerous times¹, and seen all the speculation about the reason why Western populations started getting so much heavier the past decades.

One popular viewpoint is that it's the carbohydrates and the higher insulin levels that result from consuming carbs. For instance, see Why We Get Fat by Gary Taubes. However, researcher Stephan Guyenet presents a fairly compelling case that this isn't the real cause: The Carbohydrate Hypothesis of Obesity: a Critical Examination.

In a seven-part series of blog posts Guyenet lays down a theory of his own: Food Reward: a Dominant Factor in Obesity, part Ⅰ, part Ⅱ, part Ⅲ, part Ⅳ, part Ⅴ, part Ⅵ, part Ⅷ². Or read this Boing Boing post: Seduced by Food: Obesity and the Human Brain.

It basically boils down to: our food tastes so good that we simply can't stop ourselves from eating too much of it. One study that Guyenet mentions is one where participants are fed a bland tasting liquid through a straw. They can consume as much of it as they want. Lean people take in their normal amount of calories and maintain their weight, but overweight/obese people consume very little and rapidly start losing weight—all the while claiming they're not hungry!

Although more research is required before something as complex as this can be declared settled, I find Guyenet's arguments quite compelling. Few people overeat simple, uninteresting foods. But we find it hard to eat just a little of something that tastes really good. If high palatability of our food is indeed the reason more and more people get overweight and obese, that's pretty good news, because then the solution is simple: eat blander food. Also see this (much shorter) post on Guyenet's blog: Palatability, Satiety and Calorie Intake.

¹ It annoys me to no end that they measure the fraction of the population that crosses a rather arbitrary line; in this case a BMI of 25 for healthy to overweight and 30 for overweight to obese. But the line between a healthy weight and overweight is fairly meaningless, someone with a BMI of 24.9 isn't healthier than someone with a BMI of 25.1 to any measurable degree, and nor is someone with a BMI of 29.9 compared to someone with 30.1. However, the progression from the healthy 18.5 - 25 range to the obese > 30 range obviously isn't good.

² If you see strange characters here: I used Unicode roman numerals rather than the regular I and V characters.

Permalink - posted 2014-07-29

Comparing black-and-white film and digital

▼ I've been experimenting with shooting film a bit recently, which gives me that nice retro feel. And nothing is more retro than shooting black-and-white film. So let's compare the results to the black-and-white images current cameras produce.

In addition to using some classic Ilford HP5 film (well, Ilford HP5 Plus these days), which is very similar to Kodak Tri-X, I also wanted to try out some chromogenic film. Chromogenic film is black-and-white film that is developed using the same C41 process that is used to develop regular color negatives, so you can have it processed pretty much anywhere.

However, although some chain departement stores still offer this service, in practice attempts to use it may get you stuck in a web of confusion. So it's easier to just support your local photo store that still has its own lab, especially if you don't care about prints and scan the negatives anyway. Here in The Hague HAFO runs their lab weekday afternoons so you can have your film developed and/or printed in a few hours.Both color negative and black-and-white, I think slides take longer. But in this case I went to the HEMA and although it took a week the prints came out in proper black and white without a color cast—be it with less than super strong blacks.

In any event, let's look at the same shot using different cameras/film. (Click for larger versions.) First, the iPhone 5. (Actually I took this one almost an hour later than the others, so my position and the light are slightly different.) The iPhone turns in an image that is very contrasty:

The Canon Powershot SX280 HS, on the other hand, produces a rather flat image:

The Nikon D7100 occupies the middle ground:

This is Ilford HP5 Plus film shot using a Nikon FE camera. It looks a bit overexposed but not very contrasty:

And this is Ilford XP2 Super film in a Nikon F55, also overexposed but more contrast:

At these small sizes it's not really possible to judge the grain and detail, so click the different links here to compare the different versions of the crop below. I had to leave out the iPhone version because it was shot from a slightly different angle so it doesn't really compare.

Note that for both the D7100 and the two types of film this is not a fair representation of their best results, as I used a fairly soft lens on the D7100 and not the highest JPEG resolution, while the film was scanned at 2400 DPI. A good scanner can no doubt produce better results, but mine doesn't really produce more detail at higher DPI settings, although the grain gets a bit smoother.

(The building is the Gemeentemuseum (municipal museum) in The Hague, famous architect Berlage's last building, which is designed to illuminate the artwork with daylight that's channeled from the glass roof.)

So what can we conclude?

One caveat: this is ISO 400/27° film. I'm going to shoot some ISO 125/22° Ilford FP4, too, as well as some color Kodak Ektar 100/21° and see how that turns out. But as far as sharpness and grain/noise goes, digital reigns supreme this day and age. HP5+ is surprisingly grainy most of the time, but even though it's the same sensitivity, XP2 Super has a lot less. There's also the phenomenon where scanned images, especially at somewhat lower resolutions, show noticeably more grain than oldfashioned prints or higher resolution scans. HP5+ especially suffers from this phenomenon.

However, the amount of grain visible varies a lot between different photos. Often enough, the grain gets in the way of fine detail, but sometimes it actually adds to the look of the photo. So I see myself shooting black-and-white as well as color film some more in the future, but my D7100 will still be my camera of choice in most situations.

Lest my faithful readers think I only shoot test shots, here a couple of photos that turned out nice, having a classic, timeless look. This is an HP5+ one of the Burger King at the Spuistraat in The Hague. Is the guy in white also admiring the building from 1909, or is he trying to deciding whether to have a hamburger for lunch?

And this one is of the Goudenregenstraat in The Hague shot on XP2 Super.

Permalink - posted 2014-07-13