The science of nutrition and healthy eating
The science of nutrition and healthy eating

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The science of nutrition and healthy eating

Week 2: What happens to the food we eat?

Introduction

Welcome to Week 2 of the course.

This week, you will find out what happens to food after you eat it.

By the end of this week’s study you should be able to understand:

  • the journey of food through the digestive system
  • how different foods are broken down to allow their absorption
  • what each food group does in the body for metabolism.

In the following video, Audrey Brown from The Open University finds out what some of the members of staff at the University know about their digestive system.

Download this video clip.Video player: snhe_week_2_vid_1.mp4
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Transcript

AUDREY BROWN
Today we’re going to be asking people what they think happens to the food when they’ve eaten a meal. What do they know about their digestive system? What happens to the food inside them, and how long does it all take?
SPEAKER 1
Um, beyond the fact that it gets digested, I can’t say I know a great deal.
Presumably a body breaks it up and takes what it needs and expels the rest, but that’s the extent of my knowledge, I’m afraid.
SPEAKER 2
Some of it stays as nutrition to the body, and some of it goes.
SPEAKER 3
I suppose it travels down through your digestive system and various nutrients and things get absorbed, until it eventually comes out at the other end.
SPEAKER 4
Well, it gets digested by your stomach, goes through your intestines, where all the nutrients get pulled out, and then, yeah, comes out the other end.
SPEAKER 5
Yeah, it does come out the other end. I sometimes wonder about how much additional value most of my food does have, too. Because I think I’m eating something healthy, but I don’t really know.
SPEAKER 4
Whereas I just care about what it tastes like.
SPEAKER 5
Yeah.
SPEAKER 6
Gets digested, gets distributed around my body to whatever bit needs it.
SPEAKER 7
I probably don’t know that much about what happens to my food, but I know to stick away from certain foods. Say, lots of sugars and fats, I keep away from, just because I know that they’re worse for your body. But I probably don’t know a lot about what the other kinds of ingredients do to your body.
SPEAKER 8
It gets digested and then gives me energy.
SPEAKER 9
The nutrients, I guess, get acquired into the body, and some of the less healthy ones get acquired into fat.
SPEAKER 10
I guess it’s broken down into different components and parts and then gets absorbed by different parts of the body? I think that’s what happens, isn’t it?
SPEAKER 11
I’ve got no idea. I just think it gets digested, and I don’t think of anything beyond that.
SPEAKER 12
No.
SPEAKER 10
No.
SPEAKER 13
Pretty much stomach, intestines, toilet is about as far as my knowledge goes.
INTERVIEWER
How long do you think your digestive system is, if we were to open you up and stretch it all out?
SPEAKER 1
What, specifically my intestines? [LAUGHTER] Um, yeah, well I did hear you could stretch your intestines round the world, but I’m not sure if that is an accurate assumption.
SPEAKER 6
I have no idea whatsoever. I know it’s quite long.
SPEAKER 2
I don’t know, 3 metres?
SPEAKER 13
Oh, I’ve heard this one before. It’s like 30 double-decker buses or something stupid like that.
SPEAKER 8
I think it’s long, but I don’t know how long.
SPEAKER 9
I’ve heard this in the past. It’s a fair length. You know, probably go all the way around this little field here.
SPEAKER 4
I know the intestines is a massive, massive amount.
SPEAKER 5
Sorry, can’t it--
SPEAKER 4
I don’t know how far it’d be end-to-end, like.
SPEAKER 5
But it can go on for like 6 metres or so, too. Like it’s pretty long.
SPEAKER 4
If I’ve got to give a guess, I don’t know, 20, 30 metres?
SPEAKER 3
Something like two football fields long, I think?
SPEAKER 12
Isn’t it really, really long?
SPEAKER 10
Oh, I’ve heard this before, yeah. It’s really long.
SPEAKER 11
It’s something to do with a tennis court. Or was that something else?
SPEAKER 10
Maybe it’s the length of a tennis court.
SPEAKER 12
It’s long.
SPEAKER 10
Maybe longer.
SPEAKER 12
Yeah. [LAUGHTER] It’s long.
SPEAKER 10
It’s long, yeah.
SPEAKER 5
I’ve got a feeling it’s really long. I’d guess a mile?
AUDREY BROWN
The actual length of the digestive system is about 4 and 1/2 metres, and it’s all coiled up neatly inside you. There’s the stomach, the small intestine, and the large intestine, and the food’s moved along by muscular waves. It takes about a day, maybe a little longer, to get from one end to the other.
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