Biology

Healthy Eating: Hunt, gather or farm?

This lesson is all about food and its origins. In it, you will explore the following questions:

• What did humans eat 20,000 years ago?

• What makes you feel hungry and full?

• What is a food pyramid?

• Why do we enjoy junk food so much?

• How has farming changed what food we eat?

This lesson will whet your appetite for understanding more about food!

This is a print version of an interactive online lesson. To sign up for the real thing or for curriculum details about the lesson go to www.cosmosforschools.com

Introduction: Healthy eating (P1)

It seems that nearly every week a new diet comes out that promises to help people lose weight. Some are based on sciencewhile others seem to be just fashion. One of the more recent diets that people are adopting is called the “paleo diet”. That meanseating like cavemen ate in Palaeolithic times. It is not an excuse to do away with table manners and start gnawing bones, though. Itsuggests you should try to mimic the caveman diet, eating a lot of meat, fruit, berries, nuts and vegetables but no grains, legumesor processed foods.

According to the diet, you should also fast – that is, not eat – every now and again as that’s what people thought the cavemen did.When humans had to source their meals by hunting animals and gathering berries, it was thought that people would occasionallygo hungry when there wasn't much food about.

The paleo diet is based on the idea that our digestive systems haven’t really evolved to keep up with the changes in diet since theadvent of farming.

But now there is a problem with that theory.

New research has found that hunter-gatherers actually suffered less from famines and food shortages than farming communities.What the researchers discovered is that farming communities suffered from food shortages more often because they had to stay inone place near their farms. Hunter-gatherers, on the other hand, were able to travel to wherever there were more wild plants andanimals.

If the scientists are right, it may mean another diet falls out of fashion.

Read the full Cosmos Magazine article here

Left: A caveman on the prowl. Right: Wheat is the basis for a lot of food in our modern diets. It is used to make foodssuch as pasta and bread. Source: iStock.

Question 1

Imagine: Picture yourself living in palaeolithic times, say 20,000 years ago. It would be a little bit like camping, except without a tent,any packed food, water tanks, or a sleeping bag. You would likely be living as part of a small group of humans and would spendmost days searching for food, making tools, and keeping safe from predators and harsh weather.

What do you think you would enjoy most about living 20,000 years ago? What do you think you would enjoy least?

Gather: Healthy eating (P1)

Source: YouTube & AsapSCIENCE.

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Question 1

Recall: Fatty and sugar-rich foods were easy to come by for ourhunter-gatherer ancestors. True or false?

True

False

Question 2

Recall: Eating fatty and sugar-rich foods make you feel just asfull as eating the same quantity of other, less fatty and sugar-rich, foods. True or false?

True

False

Question 3

Recall: Use the text tool in the sketchpad below to add the missing words.

Hint: the missing words are 'ghrelin', 'NPY' and 'leptin'.

Question 4

Reflect: What do you think is the main message that the above video is trying to get across?

Food pyramids are used to represent how much of each foodgroup you should eat in your diet. The bottom level, or base, ofa food pyramid represents what you should eat most. The toplevel, or tip, of the pyramid indicates what you should eat least.

The food pyramid on the right is a typical food pyramid. It hasfour distinct levels:

Level 1 consists of foods made from grains such as bread,pasta, rice and cereals.

Level 2 consists of fruit and vegetables.

Level 3 consists of meat and dairy products.

Level 4 consists fatty and sugar-rich foods.

Source: iStock.

Question 5

Research: Perform an internet search to find an image of a paleo diet food pyramid. Upload your image below.

Drag and drop file here

Question 6

Compare: What are the similarities and differences between the typical food pyramid, above, and the paleo diet food pyramid thatyou uploaded?

Similarities Differences

Process: Healthy eating (P1)

Question 1

Investigate: What have you had to eat and drink in the past week? Complete the table below.

Food and drink that you have had over the past week Food group Quantity (number of servings)

e.g. bananas e.g. fruit e.g. 3

Question 2

Construct: Based on the above table, use the sketchpad below to construct a food pyramid that represents your diet from the pastweek.

Hint: use the line tool to separate your pyramid levels and use the text tool to type out each food group from your table.

Question 3

Critique: What have you learnt from creating your own food pyramid? How does your pyramid differ from the recommended foodpyramid in the previous activity? How does it differ from the paleo diet food pyramid that you uploaded in the previous activity?

What have you learnt? Differences with recommended foodpyramid

Differences with paleo diet foodpyramid

Did you know?

Did you know that our tastebuds have evolved to help us know what we should and should not eat and drink? After all, without theability to taste, how would you know which foods are poisonous and which are nutritious?

Question 4

Hypothesise: If our tastebuds have evolved to tell us what we should and should not eat, why are delicious fatty and sugar-richfoods such as chocolate bars and cake at the tip of the food pyramid?

Roughly 15,000 years ago, humans started to grow their own food, rather than hunting and gathering food in the wilderness. Thismade it significantly easier to feed larger populations, though as mentioned in the introduction, it occasionally made somecommunities more subject to famine.

Farming has had a significant impact on food as we know it. Each year farmers would harvest the seed from the biggest and tastiestfruit to plant the next year. This process is called selective breeding, and 15,000 years of it has resulted in modern plants thatappear and taste dramatically different from their wild relatives of the past.

Question 5

Connect: Use the arrow tool to connect the wild plants in the top row to their modern relative in the bottom row.

Not only has farming changed the appearance of the fruit and vegetables that we grow, but we now process that food to create newfoods and drinks. With the right ingredients we can process wheat into bread and cacao beans into chocolate, for example. As aresult, we can now consume much more sugar and fat than would ever have been possible for Palaeolithic humans, as mentionedin the video in the previous activity.

Question 6

Calculate: A typical 375 mL bottle of soft drink contains roughly 40 grams of sugar. Sugarcane is a rich natural source of sugar andcontains roughly 4 grams of sugar for every 10 cm of sugarcane. How much sugarcane would you have to eat in order to consumethe same amount of sugar as drinking 375 mL of soft drink?

1 cm of sugarcane

10 cm of sugarcane

1 m of sugarcane

10 m of sugarcane

Apply: Healthy eating (P2)

Healthy eating ad campaign

Source: iStock.

Question 1

In this task you are to work in small groups to create your very own healthy eating television ad. Use what you have learnt from thislesson along with any additional information you discover for yourself in order to create the ad.

Complete all of your work in the project space below.

Stage 1: Research

Perform a YouTube search to find three healthy eating television ads that other people have made. Upload them below along withtwo accompanying sentences explaining what you like and dislike about each ad.

Stage 2: Brainstorm

In your group, brainstorm ideas about your ad. Think about what equipment you will need and what approach you might take (forexample, you could talk about how easy it is to eat a high-sugar diet in today's world and suggest an idea for how to combat thisissue). Use a combination of the mind map and text tools to record your ideas.

Stage 3: Script and storyboard

Write a script for your ad and draft a simple storyboard. A storyboard is a short sequence of illustrations with descriptions thatprovide an outline of the ad. You can present your storyboard as a series of sketchpads or alternatively you may download a blankstoryboard template here, photograph your finished storyboard and then upload the photo below.

Stage 4: Produce your ad (optional)

You are ready to shoot your ad! Make sure that you upload your finished product into your project space.

Note: If you wish to share your ad with your classmates, ask your teacher to open the discussion at the bottom of the page andupload your ad there as well.

Career: Healthy eating (P2)

Therese O'Sullivan has what many people would think of as a dream job - she gets paid to think about food all day. Workingas a dietician and researcher at Edith Cowan University and with the Raine Study Nutrition Group at the Telethon Institute, Thereseis very interested in how the food we eat can influence our health for the rest of our lives

Therese's passion for food and nutrition started early in life,encouraged by her mother who gave her her first cook bookwhen she was in primary school. It was natural that she wouldgo on to study home economics at high school, and thennutrition and dietetics at university.

Much of Therese's work is driven by a fascination with howfoods affect our bodies and how people choose what to eat. Shelooks at not only the physical aspects of diet, but also thepsychological. Being a researcher and lecturer has flexibility interms of work hours and location – which is particularly handynow that Therese has a one-year-old baby at home. She alsogets to travel around the world to present research.

In a study of the breakfast habits of hundreds of 14-year-olds,Therese found that the teenagers who ate from at least threedifferent food groups at breakfast time (e.g. cereal + milk +fruit) had lower levels of anxiety and depression than those whoskipped breakfast or only ate from one or two food groups. Thismeans that something as simple as adding a banana or somenuts to your cereal may have a positive impact on how you feel.Different food groups provide different nutrients, and having avariety can help make sure your brain and body get what theyneed to function optimally. One of Therese’s favouritebreakfasts is cereal with full cream milk, chopped fruit andlocally grown macadamias – that’s four food groups!

Source: Telethon Institute for Child Health Research

Question 1

Adopt: Based on Therese's recommendations, how do you think you might change what you have for breakfast tomorrow?

Cosmos Lessons team

Education Editor: Bill CondieArt director: Robyn AdderlyProfile author: Edwina BerryLesson authors: Daniel Pikler and Sally Parker