Why the chubs?

My last post dealt with the thorny issue of obesity, both it’s increasing presence in our everyday lives, and what for me is the underlying reason behind the stats that back up media scare stories concerning ‘the obesity epidemic’- the rise in size of the ‘average’ person over the last few decades. The precise causes of this trend can be put down to a whole host of societal factors within our modern age, but that story is boring as hell and has been repeated countless times by commenters far more adept in this field than me. Instead, today I wish present the case for modern-day obesity as a problem concerning the fundamental biology of a human being.

We, and our dim and distant ancestors of the scaly/furry variety, have spent the last few million years living wild; hunting, fighting and generally acting much like any other evolutionary pathway. Thus, we can learn a lot about our own inbuilt biology and instincts by studying the behaviour of animals currently alive today, and when we do so, several interesting animal eating habits become apparent. As anyone who has tried it as a child can attest (and I speak from personal experience), grass is not good stuff to eat. It’s tough, it takes a lot of chewing and processing (many herbivores have multiple stomachs to make sure they squeeze the maximum nutritional value out of their food), and there really isn’t much of it to power a fully-functional being. As such, grazers on grass and other such tough plant matter (such as leaves) will spend most of their lives doing nothing but guzzle the stuff, trying to get as much as possible through their system. Other animals will favour food with a higher nutritional content, such as fruits, tubers or, in many cases, meat, but these frequently present issues. Fruits are highly seasonal and rarely available in a large enough volume to support a large population, as well as being quite hard to get a lot of down; plants try to ‘design’ fruits so that each visitor takes only a few at a time, so as best to spread their seeds far and wide, and as such there are few animals that can sustain themselves on such a diet.  Other food such as tubers or nuts are hard to get at, needing to be dug up or broken in highly energy-consuming activities, whilst meat has the annoying habit of running away or fighting back whenever you try to get at it. As anyone who watches nature documentaries will attest, most large predators will only eat once every few days (admittedly rather heavily).

The unifying factor of all of this is that food is, in the wild, highly energy- and time-consuming to get hold of and consume, since every source of it guards its prize jealously. Therefore, any animal that wants to survive in this tough world must be near-constantly in pursuit of food simply to fulfil all of its life functions, and this is characterised by being perpetually hungry. Hunger is a body’s way of telling us that we should get more food, and in the wild this constant desire for more is kept in check by the difficulty that getting hold of it entails. Similarly, animal bodies try to assuage this desire by being lazy; if something isn’t necessary, then there’s no point wasting valuable energy going after it (since this will mean spending more time going after food to replace lost energy.)

However, in recent history (and a spectacularly short period of time from evolution’s point of view), one particular species called homo sapiens came up with this great idea called civilisation, which basically entailed the pooling and sharing of skill and resources in order to best benefit everyone as a whole. As an evolutionary success story, this is right up there with developing multicellular body structures in terms of being awesome, and it has enabled us humans to live far more comfortable lives than our ancestors did, with correspondingly far greater access to food. This has proved particularly true over the last two centuries, as technological advances in a more democratic society have improved the everyman’s access to food and comfortable living to a truly astounding degree. Unfortunately (from the point of view of our waistline) the instincts of our bodies haven’t quite caught up to the idea that when we want/need food, we can just get food, without all that inconvenient running around after it to get in the way. Not only that, but a lack of pack hierarchy combined with this increased availability means that we can stock up on food until we have eaten our absolute fill if so we wish; the difference between ‘satiated’ and ‘stuffed’ can work out as well over 1000 calories per meal, and over a long period of time it only takes a little more than we should be having every day to start packing on the pounds. Combine that with our natural predilection to laziness meaning that we don’t naturally think of going out for some exercise as fun purely for its own sake, and the fact that we no longer burn calories chasing our food, or in the muscles we build up from said chasing, and we find ourselves consuming a lot more calories than we really should be.

Not only that, but during this time we have also got into the habit of spending a lot of time worrying over the taste and texture of our food. This means that, unlike our ancestors who were just fine with simply jumping on a squirrel and devouring the thing, we have to go through the whole rigmarole of getting stuff out of the fridge, spending two hours slaving away in a kitchen and attempting to cook something vaguely resembling tasty. This wait is not something out bodies enjoy very much, meaning we often turn to ‘quick fixes’ when in need of food; stuff like bread, pasta or ready meals. Whilst we all know how much crap goes into ready meals (which should, as a rule, never be bought by anyone who cares even in the slightest about their health; salt content of those things is insane) and other such ‘quick fixes’, fewer people are aware of the impact a high intake of whole grains can have on our bodies. Stuff like bread and rice only started being eaten by humans a few thousand years ago, as we discovered the benefits of farming and cooking, and whilst they are undoubtedly a good food source (and are very, very difficult to cut from one’s diet whilst still remaining healthy) our bodies have simply not had enough time, evolutionarily speaking, to get used to them. This means they have a tendency to not make us feel as full as their calorie content should suggest, thus meaning that we eat more than our body in fact needs (if you want to feel full whilst not taking in so many calories, protein is the way to go; meat, fish and dairy are great for this).

This is all rather academic, but what does it mean for you if you want to lose a bit of weight? I am no expert on this, but then again neither are most of the people acting as self-proclaimed nutritionists in the general media, and anyway, I don’t have any better ideas for posts. So, look at my next post for my, admittedly basic, advice for anyone trying to make themselves that little bit healthier, especially if you’re trying to work of a few of the pounds built up over this festive season.

Hitting the hay

OK, so it was history last time, so I’m feeling like a bit of science today. So, here is your random question for today; are the ‘leaps of faith’ in the Assassin’s Creed games survivable?

Between them, the characters of Altair, Ezio and Connor* jump off a wide variety of famous buildings and monuments across the five current games, but the jump that springs most readily to mind is Ezio’s leap from the Campanile di San Marco, in St Mark’s Square, Venice, at the end of Assassin’s Creed II. It’s not the highest jump made, but it is one of the most interesting and it occurs as part of the main story campaign, meaning everyone who’s played the game through will have made the jump and it has some significance attached to it. It’s also a well-known building with plenty of information on it.

[*Interesting fact; apparently, both Altair and Ezio translate as ‘Eagle’ in some form in English, as does Connor’s Mohawk name (Ratonhnhaké;ton, according to Wikipedia) and the name of his ship, the Aquila. Connor itself translates as ‘lover of wolves’ from the original Gaelic]

The Campanile as it stands today is not the same one as in Ezio’s day; in 1902 the original building collapsed and took ten years to rebuild. However, the new Campanile was made to be cosmetically (if not quite structurally) identical to the original, so current data should still be accurate. Wikipedia again tells me the brick shaft making up the bulk of the structure accounts for (apparently only) 50m of the tower’s 98.6m total height, with Ezio’s leap (made from the belfry just above) coming in at around 55m. With this information we can calculate Ezio’s total gravitational potential energy lost during his fall; GPE lost = mgΔh, and presuming a 70kg bloke this comes to GPE lost= 33730J (Δ is, by the way, the mathematical way of expressing a change in something- in this case, Δh represents a change in height). If his fall were made with no air resistance, then all this GPE would be converted to kinetic energy, where KE = mv²/2. Solving to make v (his velocity upon hitting the ground) the subject gives v = sqrt(2*KE/m), and replacing KE with our value of the GPE lost, we get v = 31.04m/s. This tells us two things; firstly that the fall should take Ezio at least three seconds, and secondly that, without air resistance, he’d be in rather a lot of trouble.

But, we must of course factor air resistance into our calculations, but to do so to begin with we must make another assumption; that Ezio reaches terminal velocity before reaching the ground. Whether this statement is valid or not we will find out later. The terminal velocity is just a rearranged form of the drag equation: Vt=sqrt(2mg/pACd), where m= Ezio’s mass (70kg, as presumed earlier), g= gravitational field strength (on Earth, 9.8m/s²), p= air density (on a warm Venetian evening at around 15 degrees Celcius, this comes out as 1.225kg/m3), A= the cross-sectional area of Ezio’s falling body (call it 0.85m², presuming he’s around the same size as me) and Cd= his body’s drag coefficient (a number evaluating how well the air flows around his body and clothing, for which I shall pick 1 at complete random). Plugging these numbers into the equation gives a terminal velocity of 36.30m/s, which is an annoying number; because it’s larger than our previous velocity value, calculated without air resistance, of 31.04m/s, this means that Ezio definitely won’t have reached terminal velocity by the time he reaches the bottom of the Campanile, so we’re going to have to look elsewhere for our numbers. Interestingly, the terminal velocity for a falling skydiver, without parachute, is apparently around 54m/s, suggesting that I’ve got numbers that are in roughly the correct ballpark but that could do with some improvement (this is probably thanks to my chosen Cd value; 1 is a very high value, selected to give Ezio the best possible chance of survival, but ho hum)

Here, I could attempt to derive an equation for how velocity varies with distance travelled, but such things are complicated, time consuming and do not translate well into being typed out. Instead, I am going to take on blind faith a statement attached to my ‘falling skydiver’ number quoted above; that it takes about 3 seconds to achieve half the skydiver’s terminal velocity. We said that Ezio’s fall from the Campanile would take him at least three seconds (just trust me on that one), and in fact it would probably be closer to four, but no matter; let’s just presume he has jumped off some unidentified building such that it takes him precisely three seconds to hit the ground, at which point his velocity will be taken as 27m/s.

Except he won’t hit the ground; assuming he hits his target anyway. The Assassin’s Creed universe is literally littered with indiscriminate piles/carts of hay and flower petals that have been conveniently left around for no obvious reason, and when performing a leap of faith our protagonist’s always aim for them (the AC wiki tells me that these were in fact programmed into the memories that the games consist of in order to aid navigation, but this doesn’t matter). Let us presume that the hay is 1m deep where Ezio lands, and that the whole hay-and-cart structure is entirely successful in its task, in that it manages to reduce Ezio’s velocity from 27m/s to nought across this 1m distance, without any energy being lost through the hard floor (highly unlikely, but let’s be generous). At 27m/s, the 70kg Ezio has a momentum of 1890kgm/s, all of which must be dissipated through the hay across this 1m distance. This means an impulse of 1890Ns, and thus a force, will act upon him; Impulse=Force x ΔTime. This force will cause him to decelerate. If this deceleration is uniform (it wouldn’t be in real life, but modelling this is tricky business and it will do as an approximation), then his average velocity during his ‘slowing’ period will come to be 13.5m/s, and that this deceleration will take 0.074s. Given that we now know the impulse acting on Ezio and the time for which it acts, we can now work out the force upon him; 1890 / 0.074 = 1890 x 13.5 = 26460N. This corresponds to 364.5m/s² deceleration, or around 37g’s to put it in G-force terms. Given that 5g’s has been known to break bones in stunt aircraft, I think it’s safe to say that quite a lot more hay, Ezio’s not getting up any time soon. So remember; next time you’re thinking of jumping off a tall building, I would recommend a parachute over a haystack.

N.B.: The resulting deceleration calculated in the last bit seems a bit massive, suggesting I may have gone wrong somewhere, so if anyone has any better ideas of numbers/equations then feel free to leave them below. I feel here is also an appropriate place to mention a story I once heard concerning an air hostess whose plane blew up. She was thrown free, landed in a tree on the way down… and survived.

EDIT: Since writing this post, this has come into existence, more accurately calculating the drag and final velocity acting on the falling Assassin. They’re more advanced than me, but their conclusion is the same; I like being proved right :).

Other Politicky Stuff

OK, I know I talked about politics last time, and no I don’t want to start another series on this, but I actually found when writing my last post that I got very rapidly sidetracked when I tried to use voter turnout as a way of demonstrating the fact that everyone hates their politicians, and I thought I might dedicate a post to this particular train of thought as well.

You see, across the world, but predominantly in the developed west where the right to choose our leaders has been around for ages, less and less people are turning out each time to vote.  By way of an example, Ronald Reagan famously won a ‘landslide’ victory when coming to power in 1980- but only actually attracted the vote of 29% of all eligible voters. In some countries, such as Australia, voting is mandatory, but thoughts about introducing such a system elsewhere have frequently met with opposition and claims that it goes against people’s democratic right to abstain from doing so (this argument is largely rubbish, but no time for that now).

A lot of reasons have been suggested for this trend, among them a sense of political apathy, laziness, and the idea that we having the right to choose our leaders for so long has meant we no longer find such an idea special or worth exercising. For example, the presidential election in Venezuela – a country that underwent something of a political revolution just over a decade ago and has a history of military dictatorships, corruption and general political chaos – a little while ago saw a voter turnout of nearly 90% (incumbent president Hugo Chavez winning with 54% of the vote to win his fourth term of office in case you were interested) making Reagan look boring by comparison.

However, another, more interesting (hence why I’m talking about it) argument has also been proposed, and one that makes an awful lot of sense. In Britain there are 3 major parties competing for every seat, and perhaps 1 or two others who may be standing in your local area. In the USA, your choice is pretty limited to either Obama or Romney, especially if you’re trying to avoid the ire of the rabidly aggressive ‘NO VOTE IS A VOTE FOR ROMNEY AND HITLER AND SLAUGHTERING KITTENS’ brigade. Basically, the point is that your choice of who to vote for is limited to usually less than 5 people, and given the number of different issues they have views on that mean something to you the chance of any one of them following your precise political philosophy is pretty close to zero.

This has wide reaching implications extending to every corner of democracy, and is indicative of one simple fact; that when the US Declaration of Independence was first drafted some 250 years ago and the founding fathers drew up what would become the template for modern democracy, it was not designed for a state, or indeed a world, as big and multifaceted as ours. That template was founded on the basis of the idea that one vote was all that was needed to keep a government in line and following the will of the masses, but in our modern society (and quite possibly also in the one they were designing for) that is simply not the case. Once in power, a government can do almost what it likes (I said ALMOST) and still be confident that they will get a significant proportion of the country voting for them; not only that, but that their unpopular decisions can often be ‘balanced out’ by more popular, mass-appeal ones, rather than their every decision being the direct will of the people.

One solution would be to have a system more akin to Greek democracy, where every issue is answered by referendum which the government must obey. However, this presents just as many problems as it answers; referendums are very expensive and time-consuming to set up and perform, and if they became commonplace it could further enhance the existing issue of voter apathy. Only the most actively political would vote in every one, returning the real power to the hands of a relative few who, unlike previously, haven’t been voted in. However, perhaps the most pressing issue with this solution is that it rather renders the role of MPs, representatives, senators and even Prime Ministers & Presidents rather pointless. What is the point of our society choosing those who really care about the good of their country, have worked hard to slowly rise up the ranks and giving them a chance to determine how their country is governed, if we are merely going to reduce their role to ones of administrators and form fillers? Despite the problems I mentioned last time out, of all the people we’ve got to choose from politicians are probably the best people to have governing us (or at least the most reliably OK, even if it’s simply because we picked them).

Plus, politics is a tough business, and what is the will of the people is not necessarily always what’s best for the country as a whole. Take Greece at the moment; massive protests are (or at least were; I know everyone’s still pissed off about it) underway due to the austerity measures imposed by the government, because of the crippling economic suffering that is sure to result. However, the politicians know that such measures are necessary and are refusing to budge on the issue- desperate times call for difficult decisions (OK, I know there were elections that almost entirely centred on this decision that sided with austerity, but shush- you’re ruining my argument). To pick another example, President Obama (and several Democrat candidates before him) have met with huge opposition to the idea of introducing a US national healthcare system, basically because Americans hate taxes. Nonetheless, this is something he believes very strongly in, and has finally managed to get through congress; if he wins the elections later this year, we’ll see how well he executes.

In short, then, there are far too many issues, too many boxes to balance and ideas to question, for all protesting in a democratic society to take place at the ballot box. Is there a better solution to waving placards in the street and sending strongly worded letters? Do those methods at all work? In all honesty, I don’t know- that whole internet petitions get debated in parliament thing the British government recently imported from Switzerland is a nice idea, but, just like more traditional forms of protest, gives those in power no genuine categorical imperative to change anything. If I had a solution, I’d probably be running for government myself (which is one option that definitely works- just don’t all try it at once), but as it is I am nothing more than an idle commentator thinking about an imperfect system.

Yeah, I struggle for conclusions sometimes.