August 03, 2010

Brazil nuts

February 27th, 2010

It's been quite a long time since I last checked in with my faithful readers. Indeed, this particular note - or half of it - has been sitting on my hard drive for a very long time, I've just never found the time to finish it. I've at long last found the courage to trawl through all the pseudo-scientific and woefully inaccurate claptrap out there and search for the elusive information that I couldn't find the first time I
attempted to write this, and at long last, I've found it. Anyway, the finished result is here, even if it IS nearly two months since Christmas! :-)

Ahh, Don't you just love Christmas?? All the turkey, the family, the carols, the chocolate, the university holidays...ahh, yes. I doubt I'd be alone in saying that Christmas is one of my favourite times of year.

A lot of people say that after Christmas dinner, they feel so uncomfortably full of turkey and Christmas pudding that they literally can't move, and feel inclined to then slump on the sofa in front of the fire, watching the "Christmas day special", whatever it may be, on BBC1 for the rest of the afternoon. A peculiar ritual, is it not! Okay, so I am just as lazy as everyone else on Christmas day, and I confess my family and I did sit down and watch TV all afternoon. However, there is one aspect of this lazy afternoon that I do not generally participate in: the uncomfortable over-fullness. Personally I HATE the feeling of being over-full, I really do. I simply can't bear it, it is one of my biggest fears and something I hate more than I can ever describe to you. True to this, I usually avoid this feeling at all costs, rarely eating large meals, but snacking frequently throughout the day. Even at Christmas, this is true. Christmas day this year I had a normal-sized portion of "cow pie", as it is affectionately known in our family, mushy peas and a bit of sweetcorn. How lame! I can hear you cry! But actually, I much prefer this to a great big blowout meal with all the trimmings, because this is just simply too much food for me.

Despite this, I did manage to put on a few pounds over Christmas - not anything I'm worried or particularly care about, but it intrigues me that every year, people see Christmas as a time to stuff their guts with all the foods which they would normally keep to a limit. I attribute this weight gain not to the QUANTITY of food I was eating, but rather to its sheer calorific value. I wish I could say that I objected to my house filling up with enough chocolate to make even Richard Cadbury feel embarrassed, but I love chocolate, and the child in me was secretly grinning from ear to ear. Chocolate. Mmm, chocolate. Inevitably all of my usually healthy-ish snacks (yoghurt, fruit, cereal bars, etc) got rather rapidly replaced with chocolate, wine and dried fruit/nuts.

It is the last of these foods that claims the attention of the rest of this piece. When I was at my parents' house just after Christmas, I was forraging around in the cupboard and came across a bag of Brazil nuts. Bad news! Whoever brought those into the house made a fatal mistake - nobody can resist them! I was just selecting a few juicy specimens from the packet when my Mum came in and caught me red-handed. Holding one up to me, she said "D'you know, there's enough energy in one of these to boil a test tube full of water"...

As much as I would have loved to come up with a devastating, smart-arse retort or a flawless biological anecdote to refute this claim, alas I could not, and just stood there looking sheepish and somewhat embarrassed as I was forced to accept this bothersome little fact. I simply wasn't able to deny it; indeed, I've done the very experiment myself, and if you don't believe it to be true, check out this video: ch?v=r5hBjKeIcfU

As I'm sure you will appreciate, when you are about to eat something that you know is horrendously bad for you, HEARING about how bad it is about as welcome as a turd in a swimming pool. But anyway, I have been thinking of this ever since, and things that get me thinking usually make for amusing reading.

At first thought, to me this seems a biochemical impossibility. hy? Well, a Brazil nut weighs virutally nothing, and it just doesn't feel big enough to contain enough energy to boil water.

A paradox that has to be resolved, I feel.

Fat is the most calorific of the biological molecules. Because I'm a nerd, I happen to know that fat contains nine kilocalories per gram. By comparison, sugar and protein - the second highest in calorific value - each contain four kilocalories per gram. Now, I imagine that these raw numbers mean very little: Let me put them into context.

- A penny weighs 2.5g.
- 1ml of water weighs 1 gram (by very definition)
- The lid of a biro weighs a tiny bit less a gram
- A Brazil nut weighs 4g, give or take a bit.

A calorie is defined as the amount of energy needed to raise the temperature of one gram of water by one degree celcius. Just ponder that for a moment. That is one hell of a lot of energy. Raising the temperature of anything requires a lot of energy, because you've got to give the particles that make up the substance more energy to move around. That's what temperature IS - a measure of the average
movement of all the particles in a substance.

So, nine thousand calories - the amount of energy in one gram of pure fat - is enough to raise the temperature of nine kilograms of water by one degree. Or, if you prefer, of one kilogram of water by nine degrees. Ok, so this is getting confusing! (Nine kilograms of water, by the way, is nine litres - about half a bucket). By these comparisons, when you think about it, packing NINE THOUSAND calories into so little of a substance is a hell of an achievement, and it is easy to see why eating fatty foods quickly piles on the pounds.

Right, now let's get back to my original problem. A bog-standard test tube can hold 15ml of water (or indeed, of any liquid!) One of the requirements, it seems, of being a biologist is a total ineptitude at mathematics or arithmetic, so give me a second while I dig out my calculator...

15ml of water weighs 15g. (Ok, so I did that bit in my head - honest) So, to raise its temperature by 1 degree, I need 15 calories. Room temperature is about 20 degrees celcius, so in order to raise the test tube to boiling point, I need to increase the temperature by 80 degrees. 80 x 15 = 1200. Therefore, I need 1200 calories to raise my test tube to boiling point. So, by that calculation, a Brazil nut must contain AT LEAST 1200 calories.

I know this is getting boring, stick with me, it gets better I promise!

Wikipedia reliably informs me that a Brazil nut is, by weight:
- 0.72g protein
- 0.052g carbohydrate
- 2.76g fat
This, unless you don't trust me and are fastidious enough to want to calculate for yourself, is a total of a little bit over 29800 Cal - or if you prefer it, 29.8Kcal. (2880 of which come from the protein, 2080 from the carbohydrate, and 24840 from the fat).

Remember I said that you only need 1200cal to boil the test tube full of water? Well there are nearly twenty-five times more calories than this in our old Brazil nut - there's our answer! THAT's where the energy comes from! This also explains why, if you watched the video, the brazil nut continued to burn for another three minutes after boiling the water.

I am hoping you're still with me, but I imagine you're bored as hell and that what I say in this next sentence is going to decide whether or not you keep reading. If Brazil nuts are indeed SO calorific, then why on earth do health experts and the like say that they're good for you? Truth is, they contain a
variety of trace elements (including selenium, phosphorus, zinc, copper, manganese, magnesium, etc) which are all required in very tiny amounts for various bodily processes. In particular, Brazil nuts contain a particularly high concentration of selenium (which, if you're interested, is involved in the action of anti-oxidant enzymes in most body cells).

So, was I right to feel guilty for eating the Brazil nuts on Boxing Day? I like to think not. In order to put on "a few pounds", I would need to eat around 7,000,000 cal (the amount of energy contained within about two pounds of body fat). To gain this number of calories, by a simple calculation, I would have needed to eat 235 brazil nuts. I only ate about six. Hmm, nothing to worry about, I don't think. They can't have added that much to my weight...

Now, here I confess...
When I was writing this a few nights ago, I spent an embarassingly long time pulling my hair out and tapping random combinations of utterly irrelevant numbers into my calculator in order to try and work out exactly HOW much weight these six Brazil nuts added. YES, I am THAT sad! It just had to be found out!! After about an hour, I finally admitted defeat and phoned up Sarsie on her mobile at about
midnight to do the calculation for me. I'm "a big retard", apparently - the calculation really isn't that difficult! Arithmetic ineptitude? Big Retard? Guilty as charged! In my defense, I'd had had rather a lot of wine, and I think that at the time I would have struggled with even my two times table - she'd never believe me though - one-nil this time, Sarsie! She also made me promise to credit her in this note!

Basically, Sarah finally worked out for me that six Brazil nuts would have contributed 23.17g of my 2lb weight gain, if ALL of the energy that was contained within these Brazil nuts had gone straight to my waist. That's quite a lot, I was surprised! However, it is of course highly unlikely that ALL of those calories were deposited as fat. Why not? Let me tell you a bit about the way that the body uses the energy that's available to it; I find it quite interesting.

The body's first choice molecules for obtaining energy are carbohydrates (sugars) which are used for short term, immediate energy-requiring processes. If I were to get up now and go and make a cup of coffee, (something I fully intend to do when I get to the end of this sentence), I would be using energy
gained from glucose sugar. Likewise, if I were to go and run up the stairs a few times (which I most certainly do NOT intend to do any time soon), I'd be using energy from STORED sugar in my liver. The liver stores this sugar as a long string of glucose molecules; a polymer called GLYCOGEN. Basically, every time some energy is required, glucose molecules are removed from the end of this great big glycogen molecule and burnt to free up some energy. Make sense?

Okay, the liver only stores a finite amount of glycogen, and this is quickly depleted following physical activity. What happens when it's all run out?? If there is no carbohydrate available to it, the body will start using its fat stores. Fat from adipose (blubberous, muffin-top, does-my-bum-look-big-in-th

is tissue) will be broken down into its component parts which then enter the bloodstream and can be used by cells for energy. Thing is, like I mentioned earlier, fat contains one HELL of a lot of calories, so if you're trying to burn off enough to make a significant difference to your waistline, you gotta work it, babe!!

Now, although I said earlier that protein contains just as many calories per gram as does carbohydrate, proteins are far too precious to be broken down for energy. They're involved with millions of other body processes instead. Virtually every single process in the body is controlled at some level by proteins. Proteins are only broken down for energy only in states of severe starvation. It's the body's last-ditch attempt to save itself from death if it's not getting any sustenance. Now, I'm talking SEVERE starvation, here, When your body has virtually NO ADIPOSE tissue left on it. Think African famine victims. When this happens, the body will have no choice other than to start using protein in order to get its energy. First, non-essential body proteins will be broken down, including those biceps that you guys have spent ages building up, and girls, all the protein that makes your hair and nails grow shiny and strong. Then, as a REAL last-ditch attempt, you'll start wasting away other muscles and proteins that ARE essential. The most obvious of these is the heart muscle, which as you can imagine, hugely increases the risk of heart attacks. By the time starvation has got this far, it is a REALLY dire state of starvation that won't last much longer.

So, in light of all that, I think it very unlikely that ALL of the calories in my Brazil nuts went straight to my waist. I think I was certainly far from starving on Boxing Day - certainly not starving enough to break down proteins! I do, however, think it was quite likely that I was storing the fat away, as I did manage to eat quite enough chocolate over the whole Christmas period to provide me with enough sugar to keep me going for several months! The fat and sugar in that alone was probably MORE than enough to make me gain 2lb! I will never be able to look at a Brazil nut in the same way again, but maybe it's the chocolate that I ought to be more concerned about!

It's okay, I've given up junk food for Lent. (Well - sort-of!)

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