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Aliki ๐ฉต
30/11/2025
Biology
Biology- Diet and Nutrition
363
โข
30 Nov 2025
โข
Understanding Nutrition and Diet Essentials
Aliki ๐ฉต
@study_wabbit
1 / 3
![# SECTION 2:
DIET AND NUTRITION:
Food
Diet: what you eat
Food is needed for: Energy (Joules [J])
Repair
Growth
Keeping warm
Movement](/_next/image?url=https%3A%2F%2Fcontent-eu-central-1.knowunity.com%2FCONTENT%2FnGuTpoEzMmzQhQzGwnod_image_page_1.webp&w=2048&q=75)
Diet and Nutrition Basics
Think of food as your body's petrol - without it, you can't grow, move, stay warm, or even repair a cut on your finger. Your diet (everything you eat) needs to provide energy measured in Joules, plus all the building blocks your body craves.
There are six main nutrient groups your body depends on. Carbohydrates like bread and pasta are your main energy source, whilst proteins from meat and beans help you grow and repair damage. Fats might sound scary, but they actually insulate your organs and form part of every cell membrane.
Don't forget the unsung heroes either. Fibre keeps your digestive system running smoothly (even though you can't actually digest it), whilst water is essential for virtually every chemical reaction happening inside you right now.
Quick Tip: Remember that vitamins and minerals each have their own special jobs - there's no single "superfood" that does everything!
![# SECTION 2:
DIET AND NUTRITION:
Food
Diet: what you eat
Food is needed for: Energy (Joules [J])
Repair
Growth
Keeping warm
Movement](/_next/image?url=https%3A%2F%2Fcontent-eu-central-1.knowunity.com%2FCONTENT%2FnGuTpoEzMmzQhQzGwnod_image_page_2.webp&w=2048&q=75)
Testing for Nutrients in Food
Ever wondered how scientists figure out what's actually in your food? These simple food tests are surprisingly straightforward and might just pop up in your next practical exam.
For starch, you'll use iodine solution - it changes from boring brown to dramatic blue-black when starch is present. Testing for glucose requires Benedict's solution and a hot water bath, creating a colourful rainbow from blue through green and orange to brick red. The redder it gets, the more sugar is lurking in your sample.
Protein testing uses Biuret solution, which shifts from blue to lilac purple. For lipids (fats), you'll mix your sample with ethanol then add water - if fats are present, you'll see a cloudy white layer appear.
Want to measure how much energy is stored in food? Calorimetry involves burning food samples and measuring how much the surrounding water heats up. The formula is: Energy = mass of water ร temperature change ร 4.2.
Exam Alert: Learn the colour changes for each test - they're guaranteed to show up in multiple choice questions!
![# SECTION 2:
DIET AND NUTRITION:
Food
Diet: what you eat
Food is needed for: Energy (Joules [J])
Repair
Growth
Keeping warm
Movement](/_next/image?url=https%3A%2F%2Fcontent-eu-central-1.knowunity.com%2FCONTENT%2FnGuTpoEzMmzQhQzGwnod_image_page_3.webp&w=2048&q=75)
Vitamins, Minerals and Individual Dietary Needs
Your body is constantly changing, which means your nutritional needs change too. Vitamin D helps you absorb calcium from oily fish and egg yolks, keeping your bones strong. Meanwhile, Vitamin C from citrus fruits repairs tissues and maintains your immune system.
Iron from red meat creates haemoglobin (the stuff that makes blood red), whilst calcium from dairy products builds bones and teeth. Missing any of these leads to deficiency diseases - think scurvy from lack of Vitamin C or anaemia from insufficient iron.
Your personal needs depend on loads of factors. Active teenagers need more calories and protein than elderly people because you're growing and burning energy faster. Men generally need more daily calories, whilst women need extra iron during menstruation and more of everything during pregnancy.
Malnutrition isn't just about not eating enough - it's about poor nutrition in general, which can happen from eating too much of the wrong things or not enough of the right ones.
Real Life: Understanding your changing nutritional needs helps explain why your appetite might vary during growth spurts or busy periods!
We thought youโd never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
Most popular content: Vitamins and Minerals
Most popular content in Biology
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Can't find what you're looking for? Explore other subjects.
Students love us โ and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because itโs too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because itโs too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Understanding Nutrition and Diet Essentials
Aliki ๐ฉต
@study_wabbit
Your body is basically a complex machine that needs the right fuel to keep running smoothly. Understanding what different nutrients do and how to test for them in food isn't just useful for exams - it's knowledge that'll help you... Show more
Diet and Nutrition Basics
Think of food as your body's petrol - without it, you can't grow, move, stay warm, or even repair a cut on your finger. Your diet (everything you eat) needs to provide energy measured in Joules, plus all the building blocks your body craves.
There are six main nutrient groups your body depends on. Carbohydrates like bread and pasta are your main energy source, whilst proteins from meat and beans help you grow and repair damage. Fats might sound scary, but they actually insulate your organs and form part of every cell membrane.
Don't forget the unsung heroes either. Fibre keeps your digestive system running smoothly (even though you can't actually digest it), whilst water is essential for virtually every chemical reaction happening inside you right now.
Quick Tip: Remember that vitamins and minerals each have their own special jobs - there's no single "superfood" that does everything!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Testing for Nutrients in Food
Ever wondered how scientists figure out what's actually in your food? These simple food tests are surprisingly straightforward and might just pop up in your next practical exam.
For starch, you'll use iodine solution - it changes from boring brown to dramatic blue-black when starch is present. Testing for glucose requires Benedict's solution and a hot water bath, creating a colourful rainbow from blue through green and orange to brick red. The redder it gets, the more sugar is lurking in your sample.
Protein testing uses Biuret solution, which shifts from blue to lilac purple. For lipids (fats), you'll mix your sample with ethanol then add water - if fats are present, you'll see a cloudy white layer appear.
Want to measure how much energy is stored in food? Calorimetry involves burning food samples and measuring how much the surrounding water heats up. The formula is: Energy = mass of water ร temperature change ร 4.2.
Exam Alert: Learn the colour changes for each test - they're guaranteed to show up in multiple choice questions!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Vitamins, Minerals and Individual Dietary Needs
Your body is constantly changing, which means your nutritional needs change too. Vitamin D helps you absorb calcium from oily fish and egg yolks, keeping your bones strong. Meanwhile, Vitamin C from citrus fruits repairs tissues and maintains your immune system.
Iron from red meat creates haemoglobin (the stuff that makes blood red), whilst calcium from dairy products builds bones and teeth. Missing any of these leads to deficiency diseases - think scurvy from lack of Vitamin C or anaemia from insufficient iron.
Your personal needs depend on loads of factors. Active teenagers need more calories and protein than elderly people because you're growing and burning energy faster. Men generally need more daily calories, whilst women need extra iron during menstruation and more of everything during pregnancy.
Malnutrition isn't just about not eating enough - it's about poor nutrition in general, which can happen from eating too much of the wrong things or not enough of the right ones.
Real Life: Understanding your changing nutritional needs helps explain why your appetite might vary during growth spurts or busy periods!
We thought youโd never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
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Can't find what you're looking for? Explore other subjects.
Students love us โ and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because itโs too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because itโs too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user