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Case-lesson “To eat or not to eat? – That is the question"

Category: Personal Growth

Level (grade): 8

Topic: Healthcare

Objective: Understand the nutrition systems

What information is waiting for me here?
  • How does food affect my health and quality of life?
  • What biological and chemical reactions occur in the body?
  • What fundamental and practical knowledge will be useful for me?
  • How much does it coast to eat healthy food?
  • Improve your English
  • An attempt to cook something tasty and unusual.
6 scans of the subjects, phenomena and practices:
Why is food important?

Have you ever thought why we wish each other “Have a nice meal” several times a day? It is because food is a source of health and a way to cope with depression and bad mood. Our ability to create, enjoy life and work depends on what we eat. With malnutrition we become sick and nervous.

Why is the food sometimes tasteless and even harmful? How to find a balance of vitamins and proteins, sweet and useful products, as well as what types of food are waiting for us in the future? Answers to these questions are not hard to find.

An illustration of the ratio of products in a balanced diet is a diet food pyramid. As you can see, the diet is dominated by cereals (base of the pyramid), fruits and vegetables (second floor). The percentage of the diet of animal products is the following. Meat and dairy, and poultry, beans, eggs and nuts (third floor) is reduced, while the share of fats and sweets - even less (top floor of the pyramid).

Nutrition problems concern every person and the planet as a whole despite the fact that the volume of food produced in the world is enough to provide each person. So, why do we speak about hunger in the world?

The reasons are the following: food prices increasing, low income, natural disasters (drought, floods, and wars), inefficient agricultural technologies, the lack of equipped warehouses and a large amount of waste in consumption when people buy more food than they can eat and throw it out.

Nutrition Properties:

The food is healthy and useful only when the technologists, chefs, cooks and confectioners follow the necessary requirements to food and its basic properties:

- Nutritional value, the possibility to provide the human body with essential nutrients;

- Energy value, which is determined by the amount of energy produced in the assimilation of nutrients;

- Biological value reflecting primarily quality and amino acid composition of the protein in the food product as well as the content of other substances (vitamins, minerals, etc.).

- Physiological value, characterizing the influence of nutrients on the system of the human body.

Each person evaluates the quality of food by its appearance, freshness, smell and taste.

Knowing this, some retailers give the product an attractive appearance including the use of a nice package. At the same time the products themselves may have low quality. However, experienced consumers, as a rule, do not fall in such trap.

Some regret that there is no a single universal food product that would contain all the nutrients, even in the food prepared for the astronauts. Therefore, the world is developing towards diversity of products and their properties. For optimum power balance percentages of nutrients should be in such proportions like protein - 14%, fat - 30%, carbohydrate - 56%.

Anatomy and Physiology

Some people think about what kind of mechanical and chemical processing the food is exposed to from its assimilation to the moment of contact with the body.

More digestions begin in the mouth where it is ground by teeth and moistened with saliva. Saliva is released by the salivary glands and the glandular cells of the oral cavity under the influence of nutrients on the taste buds of the mouth and tongue.

Salivation is also stimulated by the smell of food, its appearance and even when a hungry person thinks about food. Taste reflexively stimulates the secretory function of the pancreas, stomach and intestines. Saliva is the first digestive juice, it also contains a substance (lysozyme), which kills some bacteria that contaminant food.

Under the influence of enzymes (amylase and maltose) happens a process of disintegration of carbohydrates. The chopped food moistened with saliva, forms the food bolus, which if swallowed into the stomach.

The most acidic juice in large quantities is released during the digestion of animal food. When the digestion of milk and vegetable products happen, the number of gastric acidity becomes much lower. In the stomach, food rests for a certain amount of time, depending on the type (from 35 minutes for fruit to 3 hours for bakery). Then, under the influence of rhythmic (peristaltic) contractions of muscles in the stomach, semi-solid food in small portions begins to flow with the aid of slurry into the duodenum.

Digestive juice of the duodenum, the main components of which are intestinal juice, pancreatic juice and bile, is expressed by the alkaline reaction. As a result, the acid reaction chyme becomes alkaline.

Enzymes of digestive juice digest the carbohydrates and fats. Proteins are broken down into small molecules and amino acids. Secretion of bile is in the liver, its components are the bile acids (mainly folic acid), enzymes, vitamins, salts, cholesterol and pigments (bilirubin and biliverdin).

Bile stimulates the intestinal peristalsis, prevents the development of putrefactive bacteria. But its major function - activation of the lipase. It is an enzyme that promotes the breakdown of fat. Bile acids break fats down to the smallest particle, improving their processing enzymes.

Stimulation of secretion is enhanced by the use of vegetable fats, egg yolks, vegetable fibers and vegetable crops. In the process of digestion, the active role is played by micro-organisms. Intestinal microflora is involved in metabolism. Its participation involves the formation of lactic acid, vitamins, and enzymes.

Therefore it is very important to maintain the intestinal flora in a normal state, what food should be varied and nutritious.


Much food we eat is not raw but processed. Typically, the preparation involves frying, cooking or other heat treatments, such as grinding and mixing. A lot of myths are created around cooking. Are raw fruits and vegetables healthier than the cooked one? Is it better to eat an apple with the skin and so on? Can chemistry help to answer these questions? Yes, it can!

Heat treatment switches the chemical reactions in the products. In the raw material all the vitamins and minerals are in a bound state and during the process of frying (cooking) bonds are broken.

An apple before and after heat treatment

However, there is a flip side. Heat treatment destroys harmful micro-organisms and toxins and softens products.

Substances in food composition can be divided into three groups: proteins (amino acids - the "building blocks" from which proteins are built), fats and carbohydrates.

The general chemical formulas of these groups of substances are shown in this illustration:

Another type of chemical processes used in the preparation of food is fermentation. Besides the scary and "scientific" name, this process is similar to marinating and pickling. In terms of chemistry, pickled cabbage is a fermented product.

For the fermentation process living cultures of microorganisms such as lactobacillus can also be used. Then the process is biochemical, and its products will become yoghurt, cheese, sour cream, and so on. The impact of lactic acid bacteria for food has another beneficial effect. Such products are more easily absorbed by the body.

Examples of fermented products:

Pickled cabbage


Tea is also a product of fermentation. Since drying is one of the most important stages of processing of tea leaves.

Here the superiority of the reactions of decomposition in the stomach, which promotes gastric juice, includes primarily inorganic acid. Hydrochloric acid which we use with such caution in everyday life is the central figure. Its main task is to maintain the acidity in the stomach. Also, its important task is to launch another chemical process like hydrolysis (decomposition of the substance with water).

Chemical transformations accompany the product from the stage of preparation to digest.

The Internet

Whoever wants to be fit, healthy and full of energy, should not only deal with food, but also should know where to get information about it. Under this circumstance the Internet becomes our ally, both in the choice of the recipe (or the whole system, diet, etc.) and advisor to the methods for losing extra kilos. For dieters the Internet offers a lot of commercials. These can be individual videos and channels – video diaries (blogs) on YouTube.

The Internet makes it possible to select all kinds of recipes. Often they are divided into simple step by step recipes with illustrations. There are also full video recipes.

Systems of weight loss are presented on two types of sites:

• Sites that give an idea of the different systems, diets, and approaches

• Specialized sites linked only to a certain type of food (raw food, vegan, separate, kosher, halal, etc.)

Cover Pages of sites that offer a variety of nutritional systems and vegan ones.

In addition, many sites offer calculators of calories. They help calculate how many calories are in a dish or in your breakfast, lunch and dinner. Sometimes these calculators are called analyzers calorie products.

For example, today at lunch I had a hamburger and boiled potatoes. In the corresponding field program analyzer, I enter the name and weight of the food (product):

The result is a ratio of proteins, fats and carbohydrates in it, and its calorie content. My lunch brought the body 897 kcal, knowing that, I can find a suitable calorie dinner.

Currently gaining popularity challenges are tasks that must be done by writing to the performance of the video and then posted in a social network. Along with the well-known Ice Bucket Challenge (among the participants are many famous people, such as Bill Gates, Stephen King, Mark Zuckerberg, Vin Diesel) there is a Grocery Challenge. It is rather entertaining, offering to make smoothies prepared from foods that are not always consistent and delicious.


This topic is dedicated to the numerous numbers of sites, public groups where like-minded people can freely exchange information, discuss experiments and help beginners. However, the Internet is also filled with countless false information.

The Internet may scare people who decide to go on various diets. How does someone determine what information is reliable and proven? It is necessary to pay attention to the following:

• Insufficient amount of vitamin D, and as a result, osteoporosis - brittle bones, the risk of fractures, weakness of ligaments, etc.

• Lack of essential amino acids, the network has a number of articles confirming the synthesis of essential acid microflora of the large intestine.


Business related to the nutritional system is one of the most stable, profitable and widespread industry. It is beneficial to manufacturers, retailers, distributors, transport, home and catering. Why? Because food is one of the main cost items of a person. It is no accident that the most important indicator of the standard of living for the population is considered by the food basket. It is defined as the cost of a set of essential goods.

In order to understand where there is income on food let’s consider the calculation of the manufacture and sale of chocolate.

If you and your parents or friends had lunch in a cafe or restaurant, do not throw away the bill. Examine it at home. What is the average price of the meal? How much would it cost if you cooked the same meal at home?



Which of the diets above do you prefer? Why?


Why do artists have passion to represent the food? Perhaps, because it seems to them there is an abundance of holidays or they are often hungry. After all, there is a saying that in order to paint a masterpiece the artist must be hungry.

The most impressive fine art genre is still life. Painters for centuries have competed in realism and rigor images of fruits, vegetables and beverages.

Consider carefully one of the subjects in the painting by Paul Cezanne, from which it is not clear why the artist put the ginger in a pot? It turns out that in the European family of the nineteenth century there were no refrigerators, and fresh ginger is known to rapidly deteriorate. Europeans know that ginger gives the dish a special flavor and a positive effect on the digestive system and causes appetite.

It turns out that art and cooking is historically linked with each other.

Practice - cooking

The art of cooking has its own name and it is recipes, but cooking methods and ingredients of each dish in each country are different. This is due to the peculiarities of culture, economics, historical traditions, climate and many other factors.

Indeed, food can be prepared in various ways, most of which methods have been known since ancient times. These are baking, boiling, stewing and steaming, stir-frying in oil, or over an open fire, barbecue, and grilling, smoking, as well as microwave treatment. But there are innovative methods used in cooking. For example, have you heard about molecular cuisine? What is it?

Molecular Cuisine is a modern form of gastronomic innovations, the so-called technologies of the XXI century. Its unique feature is the technology of mix processing of any product beyond recognition which connects the latest technology like molecular chemistry and … food.

The creators of molecular cuisine are the French chemists and gastronomists Paul Bocuse, Alain and Pierre Chapelle Truagroi. They became the founders of the latest culinary trends.

The cuisine which creates dishes of molecular gastronomy is a real chemical laboratory with test tubes, flasks and obscure complex instruments. It is hard to believe that culinary masterpieces created here are actually edible. First of all, the chef-chemists combine different substances and technologies of cooking food and then lay out the molecules. The most striking examples are as follows. A certain liquid solidifies into dough; meat becomes marshmallows; olive oil converts into caramel; caviar or tea with lemon are transformed into foam.

Many people are afraid to try these dishes because of their production by means of chemical reactions. However, this is misleading. Since in the process of cooking molecular cuisine uses only natural substances, food gets a balanced diet and is still considerably useful.

Nowadays molecular cuisine is an experimental area. The process of cooking, a variety of dishes based on microbiology has not fully been disclosed, and a fantasy of gastronomical geniuses is endless.

Acquire skills

• Fold the puzzle structure of the digestive tract. Name its parts and features of the structure.

• Groups of three people prepare meals (Italian cuisine – spaghetti, Uzbek – pilaf, Chinese – pelmeni, Ukrainian – borsch, American – barbecue, Japanese – sushi). They are playing the role of students from different countries.

• Make a morning menu for a week.

• Write a list of the products you ate last week.

• Add two pie charts, at the first, divide your food products per week into the following sectors: boiled food, raw food, fried food and steamed food. At the second on the following sectors: sweets, fruits, vegetables, flour, meat, and fish.

• Think of the dish pretending that it is the food of the future.

• Work with the Internet. Find the sites dedicated to the three diets. Prepare a brief presentation on five slides about your own concept of proper nutrition.

Accelerated activities


The essence of the game: Teacher prepares in advance an opaque bag with fresh vegetables and fruits (seasonal). Students should randomly choose fruit or vegetable in turn and feel the bag. The best way to organize this game is a team competition. By tactile sensations, shape, smell, to taste, they must guess what is in front of them, and put in a separate basket or box intended for vegetables or fruits. Thus, the game continues until the contents of the bag are sorted out. The winner will be a team that guesses the right amount of more vegetables and fruits.

Goal: Development of a positive mood and team spirit, the acquisition of competencies such as self-control, concentration, adaptability, ingenuity, development of tactile feelings and smell.

What competences are gained in this case

• Find useful information about products

• Ability to cook several dishes

• Understand and consult other food systems

• Make up your diet

• Provide yourself with good health through nutrition

• Study the properties of foods and gastrointestinal tract

• Communicate in English

• Ability to find quickly the necessary information and creatively use it for practical purposes

• Assimilation of specific knowledge in the field of anatomy, chemistry, the Internet

• Ability to systematize new information on the basis of acquired knowledge and their segments

• Organize and upgrade your intellectual and communication abilities


The End