Wednesday, April 21, 2010

The Secret to Weight Loss

This is a "common misconceptions" post that I've been meaning to do for a long time, and thanks to a recent article in The New York Times I finally have a good reason. More on that later.

Everybody knows weight loss is a big deal, the fact is obvious from the astounding range of products/services with weighty promises (lose 30 pounds in 30 days!!!); the advertisements assault us constantly, from every possible angle. Given that the majority of US Americans are considered overweight in a culture with highest regards only for the exact opposite build, it's really no surprise that weight loss is big business. The real surprise is just how successful such ventures are when practically all of them make explicitly outrageous claims and just as many (if not more) are wholly ineffective. The truth is that with few exceptions commercial weight loss products are simply fraudulent--they are designed to take your money, not to help you lose weight.

I know the secret to losing weight, and I'm willing to share it... for free! It is very simple, and not simple in the subtly very complicated way, just simple. Ready?

How to lose weight:  Eat less.

 It's a matter of physics. Imagine an extreme case where a person doesn't eat or drink anything; by the very laws of nature and obvious from elementary intuition, it is impossible for that person to gain weight. This would be just like setting a scale in a sealed room: it would be very silly to think that the scale might at any point suddenly measure any more weight than it has all along. Humans are magnificently, extraordinarily, incomprehensibly complex systems, but that doesn't exempt us from the laws of physics. Unless more stuff is added to a body, that body will either maintain or lose weight. In case it isn't obvious, let me remind you that abstaining from all consumption for longer than a little while is a bad idea--remember, the rule is to eat less, not to eat nothing.

Let's explore the physics in slightly more detail. The main reason we eat is to supply our body with energy; our bodies need fuel to keep the magic alive, just like a car needs gas to move. Clearly it would be a bad setup if the energy we consume couldn't be stored, like a car without a gas tank we wouldn't get very far. There are a variety of ways the human body can store energy, but the presently relevant one is best known as fat. Call me crazy, but next time you see that extra bit of flab, try being grateful--if it weren't for that "unsightly" bit of excess, a few missed meals would result in death. I don't know about you, but I'd rather have a less than optimal social image than be dead.

So fat is stored energy, but what's this energy? Is there any way to quantify it so that its consumption might be regulated? In fact, yes, there is! The energy in food is also known as Calories, which is actually a kilocalorie or 1,000 calories. A calorie is a unit of energy, just like an hour is a unit of time. If you eat 2,000 Calories in a day and only use half of them, the rest will be stored, with some portion of them being stored as fat, it's as simple as that! If you are gaining weight and it's not because you're building muscle mass, you are eating more energy than you're using. Here's the Eureka moment!

How to lose weight (revised): Eat fewer calories than you use.

But wait, what about fatty foods, exercise, and metabolism, don't these play a major role in weight loss? Lets look at each of them.

Fatty Foods
One of the strongest diet related misconceptions around is that eating foods with excess fat, saturated, unsaturated, or otherwise will lead to increased body fat. This isn't true, food fat doesn't automatically turn into body fat. Perhaps this misconception arose because lipid nutrients and adipose tissue are both known colloquially as fat, but the notion that consumed lipids will transform into adipose tissue is as silly as the notion that eating brain will make a person smarter. Anybody can eat pure fat every day and lose weight, because the amount of fat in a food doesn't matter for weight management, what matters is the amount of Calories in the food and how much food (ergo how many Calories) is consumed. It's true that fat, with 9 Calories per gram, has a higher energy density than protein and carbohydrates, which have 4 Calories per gram, but for the purposes of weight loss this is moot--all Calories in a food, regardless of the source, are accounted for by the "Calories" figure on every nutritional label. Predictably there's a fair degree of complexity in how effectively food energy is captured, but the given number of Calories represents the maximum; if you closely regulate energy intake, you will realize there are no magical foods that cause body fat. Often, however, energy intake is far from regulated, far even from monitored, and it is very easy to underestimate how many Calories are eaten in a day. One case deserves special mention: high-fructose corn syrup (HFCS), the modern sweetener du jour, has been shown in a recent Princeton study to lead to more weight gain in mice than equal amounts of cane sugar. The theory I've heard is that HFCS is far more easily digested than cane sugar, and since digestion requires energy, HFCS results in more energy than an equal amount of sugar.

When people think weight loss, they usually think exercise. It's always a point of contention when I say it, but exercise does very little to hasten weight loss. The reason is that the body burns a lot of energy no matter what its doing; for most people exercise causes only a marginal increase in energy consumption from the already high baseline. Remember the NYTimes article I mentioned? Here's a quote from it:
“In general, exercise by itself is pretty useless for weight loss,” says Eric Ravussin, a professor at the Pennington Biomedical Research Center in Baton Rouge, La., and an expert on weight loss.
The exception here is athletes, whom require many more calories than everybody else. This is because athletes have bodies that are especially efficient in utilizing energy--in other words, they have a higher basal metabolic rate. For those of us who aren't professionally physically fit, the connection between exercise and weight loss isn't anywhere near as clear cut. For more information on this topic I recommend reading the aforementioned NYTimes article: "Weighing the Evidence on Exercise." Beyond weight loss, keep in mind that frequent aerobic exercise is universally acknowledged as a critical component in the maintenance of cardiovascular health.

One of my pet-peeves, if you can call it that, is when people disseminate false information. We live in an age when almost the full knowledge of Earth is accessible on demand, so the reasoning goes that it's time we stop defaulting to wild speculation and just google it. Of course I have nothing wrong with wild speculation, my displeasure arises when the speculation is presented as fact. I'm bringing this up because it's relevant to the topic at hand, metabolism. Everybody has heard the word, it's used all the time, especially in regard to weight management, but what does it mean? What is metabolism? For all the mention it gets, I'd think everyone would be familiar with what exactly was being referred to. If you visit the Wikipedia page for metabolism, you might find that the subject is rather complicated; the summary refers to cellular respiration, metabolic pathways, and the carboxylic acids that are part of the citric acid cycle. That doesn't sound like weight loss! Metabolism is something of a shotgun term that refers to the chemistry of life. The basal metabolic rate is a bit more specific, as it refers to the amount of energy an organism expends while at rest and in a post-absorptive state. Since basal metabolic rate is roughly energy expenditure, it must be able to indicate how many Calories are needed to manage weight, and indeed it does. Interestingly enough, metabolic rate is strongly correlated with lean muscle mass and the same figure has been arrived at for all people: 16 Calories per pound of lean mass per day. This means an estimate for how many Calories you need each day can be found by multiplying your lean mass by 16. This also indicates what has been shown in other studies as well: the best known way to increase the basal metabolic rate is by increasing lean muscle mass.

Just one final note: losing more than a pound or two a week is neither healthy nor permanent.

Sunday, April 18, 2010

Nexus One, an Android

I've had an iPhone since shortly after they were first released, nearly three years now. For the most part, I've enjoyed it. These days, particularly when it comes to electronic devices, three years is a really long time; as such, it's almost difficult to recall why the iPhone had the hype it had. One thing to recall is that the app store, which is now probably the most attractive and well known feature of the phone, didn't exist when the phone first came out. The reason the iPhone was viewed as revolutionary (and that it was) was because it was the first cell phone to give what could be called functional access to the Internet, where most all websites were available to a mobile phone without any modifications. Clearly the Internet has revolutionized society; the movement from being available only on home computers to being available almost anywhere with cell reception is undoubtedly a movement that has been similarly transformative.

The availability of the whole content of the Internet, many Terabytes of information, on a diminutive device feeling like a polished stone, is practically inconceivable to me. But the notion is one conceived many times over in the science fiction canon. The most obvious example I know of is the device which shares the name of the book in which it resides: The Hitchhiker's Guide to the Galaxy. In his remarkable series Cosmos, Carl Sagan repeatedly fantasizes about perusing the fundamentally similar, fictional Encyclopaedia Galactica, a compendium of all the knowledge gathered throughout the existence of an intergalactic species. Both of these bits of media originate around 1978, a time in which something like the iPhone and the Internet must have been considered far out by any reasoning; it is apparent that at least two foraward thinking people saw such a device as a product of civilizations living on a galactic scale.

From 1978 the iPhone must have been a long way away, considering the primitive original Apple Macintosh didn't even hit the market until January of 1984, though development started in 1979. The Macintosh had an 8 MHz processor, 128 KB of RAM, and a 9" 512x342 monochrome display. Fast forward 23.5 years, and though our progress in intergalactic exploration hadn't much changed from naught, our computers had made unexpected advances! The original iPhone runs at 412 MHz, 128 MB of RAM, and a 3.5" 320x480 18-bit color display--it's roughly 52 times faster, has 1,000 times more memory, and a far superior display. It fits in a pocket and can run all day without needing a charge, it can replace books, newspapers, televisions, and the list goes on beyond any reasonable expectations.

Three years later, the revolution of Internet on a phone has taken place, and giant leap taken all that remains is incremental improvements: the Nexus One. This past December there was a buzz about the web as rumors of a Google phone spread. The buzz persisted for a little while and then mysteriously subsisted. The Google phone arrived almost as if it were secret all along, almost as if it remained a secret--from what I've read, the sales of the device aren't remotely as impressive as those for the iPhone. But for what it lacks in popular perception, it makes up for in spec: 1 GHz processor, 512 MB RAM, 3.7" 800x480 display, or about twice an iPhone. Having just recently mentioned that GHz isn't a very important measure, I'd be foolish to regard that as a concrete measure of performance; it isn't, but the Nexus One noticeably outperforms the iPhone in every respect. Interestingly enough, the Nexus One matches or exceeds the recently released iPad in almost every spec except for screen resolution--it's truly a remarkable device.

One of the things about today's cell phones, also called smart phones or super phones, is that they're actually powerful little computers masquerading as phones. The iPhone does a very good job at hiding the power under it's hood, and this is very much one of the reasons I chose to go with a Nexus One over another iPhone; the Nexus One has only a thin veil to hide the fact that it's a computer running a version of Linux. In order to write an application for the iPhone, one needs to pay Apple about $100 to apply for the opportunity. If they choose to accept you, there are a number of steps to follow, including authorizing a particular device, associating it with a particular machine, writing particular code, and accepting a very hefty agreement which includes conditions such as not displaying your device in public and the right of Apple to take ownership of your code without notification or recompense. The $100 only covers one year--every year requires another $100 to continue participation. I did go through this process at some point, but I didn't get as far as getting code onto a device before my membership expired; after that, I gave up. The Nexus One is a different story: anyone can write anything and put it on their phone at any time, for free. The first day I had my new phone I had a custom application uploaded to it. The second day I gained root access, installed a custom bootloader and a modified version of the Android operating system known as CyanogenMod; in other words, I now own my phone.

The subject of science fiction is relevant for one last note: the name Nexus One comes from the most advanced android in a story called "Do Androids Dream of Electric Sheep?" better known as "Blade Runner," by Philip K. Dick.

Nothing says "I'm a geek and I know what I'm doing" like a command line:

One thing that really stands out about the Nexus One versus the iPhone is the much higher resolution display (click to see a version large enough to tell the difference, also note that some aliasing in the form of red, blue, and green banding may appear depending on your monitor):

Here's a side by side comparison:

There are still a few things I like about one more than the other, but the power of the Nexus One is that I can change nearly everything as I see fit--the same most certainly cannot be said for the iPhone.

Monday, April 12, 2010

Music for a Season

I can't speak for the daylight hours immediately passed thanks to a fittingly peculiar sleep cycle (which I happen to appreciate despite, or perhaps for its general incongruity), but early this morning I emerged from in-doors to find the weather teetering upon perfection. It was the type of occasion that calls for the composition of a remarkably accessible, evocative, and timeless piece of music; fortunately for me, given my lack of musical training and the otherwise moderate difficulty of composing such a sound, someone has already taken and decidedly owned the feat. Thus it is with endless gratitude to, and for the inspiration of, Antonio Vivaldi, paragon of baroque classical composition, that I present music fit for this season, the 3rd movement of Spring, from The Four Seasons:

Wednesday, April 7, 2010

SparkFun SEN09423 integration issues

Anyone seeking to use SparkFun's SEN09423 breakout board for the LPY530AL as a position sensor should be advised that the two 4.7 µF capacitors (C1 and C2 on the schematic) used for the high pass filter need to be removed and the contacts bridged. This image shows which tiny bits are of concern, however note that it seems the resistors indicated therein do not need to be removed. This information comes thanks to a few people who know what they're doing (which excludes myself), as discussed on the SparkFun forums here and here. From what I gather this may be an issue with numerous (all?) SparkFun breakouts including ST rate gyros, the two threads alone implicate boards containing LPR530AL or LPY530AL, including the IMU 6DOF Razor. This is a particularly odd case because Inertial Measurement Units are mostly used for dead-reckoning, and the inclusion of these caps will effectively frustrate anyone with such an intent. As far as removing them, good luck! Here's my own picture of how gigantic these caps are:

I found the best luck (given a fine tip soldering iron) with adding a little solder to one side so that solder wick can get most of it. Then just heat up the other side and push gently. The first one I removed took the contact pad with it, if that happens to you you may or may not be high and dry. I managed to salvage the situation by drawing between the appropriate areas with a pencil. In case you weren't aware, graphite is conductive--clearly this is a handy bit of information on occasion.

For a slightly more general audience, here's some interesting information. The capacitors pictured are about 0.065 inches wide, or 1.66 mm; the skinny dimension of the penny pictured is about 1.52 mm. I said these capacitors are gigantic, and relatively speaking this is true! Relative to molecules, light rays, and subatomic particles sure, but also relative to the vast majority of capacitors out there. We will get to how in a minute, but first a brief overview. The electronic components most of us are used to seeing are the ones attached to those (usually) green boards also known as circuit boards, like this one:

These days most circuit boards we encounter are printed circuit boards or PCBs, called such because the production process resembles printing to varying degrees. The principle elements of a PCB are, put simply, fiberglass, copper or other conductive metal, and solder mask. The fiberglass makes up the board-ness, the copper is akin to wiring for conducting electricity amongst the components, and the solder mask, the colored part, is a coating that solder doesn't stick to, in place so that connections aren't made accidentally by wandering solder. Not too long ago, I thought the PCB was made of silicon; after all, electronics are associated with silicon, and from a naive perspective the shiny green board looks like something that might be called silicon. But if that's not it, where's the silicon? In an IC of course! These days most all the action of an electronic device happens in an Integrated Circuit, which looks something like this:

Inside that chunk of plastic there's a wafer of silicon, which could contain anywhere from hundreds to Billions of electronic components. Wouldn't it be nice if there was a window that showed the silicon? Like this one?

Instead of discrete components like the capacitors I shared above, these components are formed by spraying (very precisely) successive layers of various chemicals in a process called photolithography, resulting in something like a miniature PCB. The CPU is the biggest, most complicated IC in the box that is your computer (unless you have a very fancy video card), and because of this it looks different than all the others. For one, you can't even see it, it's hidden underneath a big heatsink, which is there to help get rid of all the electricity that turns into heat in the CPU (the process is conceptually similar to heat generated from friction). CPUs generate so much heat that one would burn itself to a crisp almost instantly without a heatsink. But even if you remove the heatsink (after you've turned off the computer), modern processors have another metal plate which hides another sealed package that finally contains the silicon. Here we're finally at the land of magic: as of now, April 2010, Intel has a 32 nm manufacturing process, which means that the typical component width is less than 32 nm. This also means that the 1.66 mm wide capacitor above is about 52,000 times wider than a single component on a 2010 Intel CPU, or, relatively gigantic. Granted, most things we know are relatively gigantic compared to 32 nm, particularly since that's quite a bit smaller than the shortest wavelength of visible light--violet, at 400 nm. Reality check: we're making electrical components so small that a ray of light can't even hit them, so small that even the most powerful microscope couldn't see them, way smaller than the average bacteria. Really!? Apparently that's not enough, industry projections have us with 11 nm chips in 2022, which would make each component about the same width as 55 carbon atoms. Interestingly, the first time a single carbon atom was photographed (after a manner) was 9/2009. Of course, there are certain problems that what we know as computers, that is Turing class machines, can't solve--certain problems that could be described in a hundred or so lines of computer code that would take a computer the size of the universe longer than the universe is supposed to exist to solve. Not content to take limitations as they're handed to us, work is well under way to develop a different class of computer: the quantum computer. Quantum computers are very different in that they can take very specific problems, like the one I just mentioned, and solve them instantly. I don't know enough about quantum computation to judge if they'll ever reach the ubiquity our Turing machines have, but I can say one thing for certain: there's not much certainty in the future! Intel will probably plug ahead and reach 11 nm in 2022, but the real question is will that even be relevant? I'm willing to bet not, it almost seems like sitting in 2002 and projecting that by 2012 our CPUs will run at 11 GHz; as it turns out, GHz aren't all that important. Take a top of the line 3.8 GHz Pentium 4 from 2004 and I assure you a 1.8 GHz chip from today will outperform it. Maybe the state of the art in 2022 will be a 100 MHz chip with a million cores--only time will tell.