The tale of the tortoise and his nose.

(.. or the story of what happens to the food we eat)

By: Keith Ross Illustrations by Megan Ross

 

Not all tortoises need to hibernate, but Chloe’s did. He was a Hermann’s and was around 10kg. He was a birthday present 4 years ago and since then both she and the tortoise had grown. This year she helped her mum make Esio ready for his winter sleep. It was important to weigh him every week, her mother explained, but when Chloe saw that he was losing around 100g every week she was alarmed. 

 

“He not poo-ing or wee-ing, so what’s happening?”

“You remember we fed him well up till the time we started his hibernation routine? Well he has to use that food to keep him alive whilst he sleeps.”

“But I thought our food went down the toilet when we’ve used it, and he’s not made any mess at all?”

“Well a little bit of our food does get flushed away, that’s true, but most stays in our bodies where it is useful.”

“So if Esio’s food stays in his body why is he losing weight?”

Chloe’s mum sighed: “I think you’re too young to understand – but would you like me to try to tell you the story of what happens to the food you eat?” The 9-year-old’s eyes lit up:

“Please!”

In the bathroom Sandra had an accurate weighing scales: “This is what we’ll use to help you make sense of it all – it will take a couple of days though.”

They were about to have their supper, “Don’t sit down yet, come and be weighed – we’ll see how much food and drink you take in.” Supper was fish fingers, rice and peas washed down with real lemonade and followed by some yoghurt.

“Wait, Chloe!” she was about to run outside to play, “don’t forget we have to weigh you after you’ve eaten.”

Sandra made out a chart for Chloe to fill in. She proudly made her first entry: supper (food and drink) – 800g. She also recorded a before and after weight each time she went to the toilet.

“We’ll weigh you just before you go to bed and you can weigh yourself again when you wake up.”

Chloe was awake early, as if it were Christmas morning, and rushed to weigh herself.

“Mum, the scales have gone wrong – I’ve lost half a kilo overnight, and I’ve not done a wee or anything! I thought I was supposed to get bigger.”

“Don’t worry – it happens to everyone, including Esio during his sleep – and we’ll soon see why! Get dressed, have breakfast and we’ll get you re-weighed before you’re off to school.”

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“We’re doing an ex-perry-ment” she beamed at her teacher as she bounced into the classroom. “We’re trying to find out where all the food I eat goes, and why my tortoise is getting lighter as he has his winter sleep.”

“Well, the simple answer is that food goes in at the top out at the bottom!”

“But my mum says it is only the unused bits that go that way – what about the bits we keep inside for us to use?”

“Ah well you see you need your food to help you grow, and it gives you energy, so the rest is used up that way.”

Chloe related all this to her mum after school. “I think we’ll find a more interesting answer tomorrow when we have all our measurements. By the way, did you eat all your packed lunch and drink we weighed this morning – I hope so!”

She took her daughter's hands in hers “You must understand, Chloe, that food is made from stuff, and it cannot just disappear – we have to find out where every gramme of food and drink has gone that you and Esio have eaten and drunk. Your teacher is quite right: your food is used to make you grow and it is a sort of fuel to give you energy, but food doesn’t just get used up and turn into energy. Time for your tea, so onto the scales please!”

By the time the third morning came Chloe’s chart was full of figures. “There’s so much to add up and subtract – I’m going to show my teacher how much arithmetic I’ve done!”

With a little help from her mum, she worked out that she had eaten and drunk 7kg, but that she had produced only 200g of poo and 1.6 kg of wee. Although she lost around half a kg each night her weight remained pretty much the same each day when she weighed herself before supper.

“So, Chloe, what do you make of all this?”

“Well, I should be 7kg heavier after eating all that food, but I have lost nearly 2kg when I poo and wee, so I should be over 5kg heavier. I seem to lose some of it by magic overnight whilst I am sleeping, just like Esio, but what has happened to it all?” Chloe looked genuinely puzzled.

“Listen, love, you’ve been thinking of where food gets into and out of your body, but can you think of anywhere else where any other stuff comes in and out?”

“Well there’s your mouth on top and your poo and wee holes down below, but we’ve thought of those already?”

“What about your nose, Chloe?”

“Oh, right. But that’s just the air we breathe in and out to keep us alive?”

Sandra smiled and winked: “There’s not much point in breathing all that air into our lungs only to breathe it out again,” she explained, “Our lungs are the place where the air gets into our blood to be carried round our bodies.”

“I thought you said blood carried our food?”

“So I did! Okay, let’s think about that for a bit: as you say, we need to get the food we eat to enter our blood – first of all it has to be broken into smaller bits …

“Oh yes, we learnt that in school – it’s called digestion.”

“And it’s only the bits that can’t be broken up, that can’t be digested, that stay in our long intestine tube and come out when you do your poo. All the good bits are now safely in the blood to be taken round the body to where they’re needed. Most of this food is used as a fuel to give you energy. That’s what the air is used for, but to help you understand this we must do another experiment – I’m going to pump up your football so it becomes very hard.”

It had been several weeks since Chloe had played with her football and it was distinctly soft. She’d like to have it back bouncy again. “It will feel lighter” she said.

“OK it may bounce better, and feel lighter, but what will happen to its weight?”

“Well air is invisible so maybe it’ll make no difference?”

This is where the very accurate weighing scales came into their own. Chloe started pumping and when it got too difficult her mother took over. When they re-weighed the football it had gained more than one gramme. To make sure they had weighed correctly they let the air out – and it lost a gramme, pumped it up and it gained a gramme.

“You see air is a real stuff. When it moves fast, when it’s windy, it can do all sorts of damage and if you add it to your football the football gets heavier.”

“Oh no, that makes things even worse – if every time I breathe in air is added to my blood, I’m going to get even heavier, but we are trying to find out why I don’t get heavier with all the food I’ve eaten, and why Esio is actually getting lighter!”

“Anyway, enough of this, time to light the barbecue – would you like to help?”

Chloe made a pile of small sticks stacked on some paper and built a pile of charcoal round them all. She carefully struck the match and watched the paper and sticks start to burn. Soon the flames faded and it looked like it had gone out. “Here, take the bellows and blow gently into your pile.”

“Wow, each time I blow, the charcoal glows bright red – the bellows really help the charcoal to burn!”

“OK, so air is needed to get energy from the charcoal. Without air the charcoal goes out. Maybe we need the air for the same reason?”

“ … and I thought you’d stopped talking about the problem with Esio when you asked me to help with the barbecue!”

“Just another experiment, dear. Whilst we wait for the charcoal to get really hot I think we are ready to find out what really happened to those 5kg of food you ate, and the 100g that your tortoise loses every week.”

They sat down together watching the red glow from the charcoal invade the whole pile.

“Some foods you eat are mostly to provide energy, like potatoes, bread, pasta and rice – they are called carbohydrates: carbo-hydrates. These are actually fuels, like the charcoal. In order to provide energy they have to ‘burn’ - not with a flame – that would hurt! – but they have to combine with the air you and Esio breathe in. Think of it as if the bellows were the lungs of the barbecue. Actually it is only a part of the air that’s used – a gas that begins with ‘O’?”

“Ox .. Oxygen – yes I know about that – when Gran was ill in hospital they had to give her oxygen – so they were just giving her air?”

“Air is only a fifth oxygen, but Gran needed it to be stronger, so they gave her oxygen on its own. Let me ask you another question – do you know what ‘dehydrated’ means?”

“Is it when you badly need a drink? … and if Esio did a wee during his long sleep it said he would become dehydrated and we’d have to wake him up.”

“Exactly – the word hydrate is another word for water. So carbo-hydrates are substances made from carbon, carbo- and water, hydrate. Do you remember the other day when I forgot about the potatoes that were cooking?”

“Oh yes – what a mess – the pan was black, and there was that burnt smell!”

“Well, the heat from the stove broke the potatoes apart and we got carbon – the black stuff – and water, which came off as steam.”

“but … but, I want to know why Esio is losing weight and you keep changing the subject, Mum!”

“Patience, Chloe, I’m not changing the subject – what’s burning to cook things on the barbecue?”

“You mean the charcoal?”

“Exactly. The black charcoal and the blackened potatoes are both the same thing – they are both carbon. And carbon is a fuel – a fuel that needs to join with oxygen to provide energy.”

Sandra spread out the hot charcoal and started to cook the kebabs she had prepared.

“Whilst the food is cooking I think we have time for some answers, are you sitting comfortably? Why don’t you begin to tell the food story to me and I’ll help you out when you get stuck. Start with when you put your food in your mouth ...”

“Well, I know that I chew my food and then I swallow it. It gets digested so the good bits can get into my blood. And the rest, not very much, comes out as my poo. I know that some of the good bits are used to help me grow. Then you said some of our food is a sort of fuel. Did you say it kind of burns? And you said something about oxygen from air being needed which also gets into my blood from my lungs…. So far all that is happening is that more and more stuff is getting into my blood – I hope it doesn’t all spill out!”

“Remember when you used the bellows? What happens is that the oxygen from the air joins with that black carbon. It is this coming together of the fuel and oxygen that provides the energy. When they combine they form a new gas called carbon dioxide.”

“A new gas? Now you say I’m getting pumped up like a football with a new gas. Mum – this just makes me bigger and bigger!”

“Hmm, maybe that would happen if the gas stayed inside you. Think about what happens to your weight over night – the half a kilo that you lose – and the 100g Esio is losing every week. How do you think this leaves your body? Neither of you did a wee or a poo. But what were you doing all night long?

“You mean dreaming?”

“No, silly, breathing! When any part of your body needs energy – say your heart – the carbohydrate from your food and the oxygen from your lungs spring together forming carbon dioxide, not as bubbles of gas but dissolved in the blood. It is carried back to your lungs where it is released so you breathe it out.”

Sandra got up and turned the kebabs over. “So here is the final answer you have been pestering me for. It is the reason why both of you lose weight when you sleep and it explains how most of the food you both eat eat leaves your bodies.”

She took a deep breath and looked at Chloe, wide eyed and expectant: “All the oxygen that enters your blood comes back out again – but it comes out joined with carbon from your fuel-food. All that black stuff, the stuff you saw when the potatoes burnt, joins with the oxygen in air you breathe in, and you breathe it all out.”

“Are you telling me that 5kg of food have turned into virtually nothing which I have just breathed out!”

“Not nothing, Chloe, remember that the air we pumped into your football weighed more than a gramme. If that had been carbon dioxide it would have been nearer 2 grammes. Count it up – with every breath you take in oxygen and with every breath the oxygen comes out again but now with a bit of carbon attached. Over two days that adds up to quite a bit, and for a tortoise it’s the same thing.”

Chloe’s puzzled look gradually relaxed. First she seemed calmed, then she began to smile – a cunning smile.

“Wow, I think I get it. The air we breathe in picks up our food and it all floats away when we breathe out again – tomorrow I’m going to astonish my friends. They’ll all say their food comes out as poo, but I will tell them they are wrong. I will tell them that most of the food they eat goes in through their mouth and comes out of their nose when they breathe out! And all the extra food we gave Esio before he hibernated is joining with the air he’s breathing and is coming out through his nose too!”