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


Category: Personal Growth

The level (grade): 9

Subject: Health, safety and medicine lessons

Objective: To get understanding of the nutrition systems

What information is waiting for me here?
  • How does food affects my health and quality of life?
  • Critical thinking while choosing dishes.
  • What biological and chemical reactions occur in the body?
  • The problem of choosing a diet in different periods of life.
  • What fundamental and practical knowledge will be useful to me?
  • How much is "to eat good "?
  • Improve your English
  • An attempt to cook something tasty and unusual.
9 scans of the subjects, phenomena and practices:
Why is food important?

Have you ever thought why do we several times a day wish each other “have a nice meal”? This is because food is a source of health and a way to cope with depression and low mood. From what we eat depends on our ability to enjoy life, work and create. And 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, 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 - 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 apply to all: 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. But why do we speak about hunger in the world?

The reasons are simple: constant increase in food prices, low income, natural disasters (drought, floods, 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 be of 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: Protein - 14%, fat - 30%, carbohydrate - 56%.

Anatomy and Physiology

Few 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 digestion begins 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 begin 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.

Systematic and critical thinking

The world of food is so varied that it is not easy to figure out what to prefer. However, opening the menu, we often see icons indicating the specific types of food: traditional, raw food, vegetarian, kosher, separation, and others, including special diets that are significantly different from each other.

Types of food

Let's start with the traditional food, the main feature of which is heat treatment of the products. It is preferred by healthy people for whom food is primarily a way to maintain the normal functioning of the body and the pleasure of eating.

The traditional attribute, therapeutic and preventive nutrition, is recommended for athletes, ballet dancers and circus, the elderly and pregnant women.  Specialized nutrition for ill people is designed to prevent recurrence of the disease and more rapid recovery.

Unconventional considered: raw food, vegetarian, kosher and separate meals.

Raw food diet

This type of food is often chosen by the one who wants to cleanse the body and lose weight. This choice is preferred for the fact that many of the vitamins, enzymes, and almost all useful properties of food are lost during heat treatment. In addition, some research scientists confirm that eating raw plant foods (vegetables, fruits, herbs, nuts, grain cereals), and seafood (fish, mussels, shrimps), improve health and increase longevity.
The fact is that in addition to the body’s own digestion humans have microflora decoupling and membrane digestion.

Microflora decoupling occurs only when a person consumes thermally unprocessed foods. A membrane digestion is the main protection of the body from being hit by large particles. Thus, the nature inherent in humans is characterized within four species of digestion, and most people use only two basic ones.


Vegetarian eating is based on the exclusion of foods from the menu; such as meat, cheese, milk, cottage cheese, and seafood. Some zealous vegans do not consume honey. Preference is given to foods of plant origin, and, in contrast to the raw food diet, vegetarians use all types of heat treatment.
In vegetarianism a person uses about 300 kinds of vegetables, root crops, about 600 species of fruit and about 200 kinds of nuts. The sources of protein are nuts, legumes (especially soybeans, lentils, beans, peas), as well as spinach, cauliflower, kohlrabi and wheat. The sources of fat are vegetable oils - olive, sunflower, linseed, hemp, mustard, coconut, beans, corn, walnut, poppy seed, almond, cottonseed, etc.
Vegetarianism recommends the following proportions in the diet:
• 25% - raw leafy and root vegetables in season in the form of salads;
• 25% - raw fresh fruit or soaked dried well;
• 25% - green and root vegetables cooked in the fire;
• 10% - proteins (nuts, cheese, dairy products);
• 10% - carbohydrates (all kinds of cereals and cereal products, sugar);
• 5% - fats (butter, margarine, vegetable oils).
The use of spices and vinegar is excluded.

The World Health Organization is ambiguous to vegetarianism. It is believed that the meat is not only useful, but that also the depletion of meats can increase the risk of certain diseases of the cardiovascular system and gastrointestinal tract. However, the diet must necessarily present animal protein (approximately 30% of the total allocation protein).

Kosher food

Many people have heard of Kosher, but do not always know exactly what it is. We will better understand this form of nutritional diet through examples of the individual products:
Meat. It is permitted to eat meat of cloven-hoofed ruminants. The famous "Jews do not eat pork," is explained not by the taste preferences. The fact that the pig though artiodactyl but not ruminant. (What is the basis of this sentence? It is incomplete and sort of hanging in the paragraph.) Pork is not kosher because of the fact that no pig chews the cud, but not because it is "the dirtiest" animal.
It is believed that the sick or killed in hunting animals are not suitable for food. Therefore, in 1998, McDonald`s changed hamburger cooking technology for the Jews. In Israel, meat snacks is not prepared on a griddle, but at charcoal.
Fish. Signs, that fish are kosher, are scales and fins. Catfish, eel will not appear on the table of those, who keep kosher, as well as the rest of marine life: lobster, shrimp, oysters and crabs. Red caviar is considered kosher, and black is not.
Fowl. Traditionally poultry is allowed: chickens, geese, turkeys and pigeons. Among the non-kosher are an owl, an eagle and a pelican. Many of the names in the descriptions of the birds from the Torah haven’t been managed to identify.
Amphibians, insects and arthropoda. Torah forbids eating worms, frogs, snakes and insects. It allows eating only four species of locusts.
Dairy and meat products. By the laws of kashrut it is prohibited to mix dairy products with meat. So the sandwich with sausage and cheese is canceled. The time interval between the meat and dairy foods according to the community can be 1, 3 or 6 hours. Between the dairy and meat it is from 30 minutes to 2 hours.
Bread. Homemade bread is kosher for Jewish and in non-Jewish bakeries bread can be eaten if all ingredients are kosher.
Preparation. Dishes for receiving meat and dairy foods are stored separately, and in wealthy homes even the kitchen is organized separately between dairy and meat.

Separate food

Logically, everything is simple: you must eat only compatible products. However, in practice it is much more difficult to implement. From supporters of this type of food, that causes a lot of conflicting opinions, it requires remarkable strength of will and adherence to a strict regime of life. We must constantly observe the eight rules of separate food:
• 1. Do not mix foods rich in carbohydrates and acidic foods;
• 2. Do not mix starches and proteins;
• 3. Do not mix different proteins;
• 4. Do not eat fats with proteins;
• 5. Do not eat proteins with acidic fruit;
• 6. Do not mix starches and sugars;
• 7. Do not eat different starchy foods;
• 8. Do not combine milk, melon, or watermelon with any other products.
Choosing a method of separate nutrition, a person sacrifices the majority of usual and favorite childhood dishes: potatoes with fish, pasta with a cutlet, sandwiches with sausage and cheese, etc.

Some kids think that if you divide a multi-stacked hamburger apart and eat them separately, it will be "separate meals." In fact, the nutrition system in McDonald’s has other very attractive properties. Firstly, they still provide a rapid, visually appealing, clean, bright and inexpensive food. Secondly, it is fashionable over what advertisers and marketers have tried. However, it cannot be said that the food is very nutritious and healthy.

Tasty breakfast

A big problem for students is food at the school: in the dining room it is often tasteless, and not all kids want to take breakfast from home. Pocket money, which parents give their children to spend on food, is often spent on fun and enjoyment. Therefore, what is becoming more common, are packed breakfasts or lunches, pre-cooked in a wide variety in special factories or sold in supermarkets. In the future they will become more widespread, although the breakfast prepared by mom or grandma will still be tastier.


Which do you prefer, meals cooked at home or at school? Why?


Many foods we eat are 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, and is it better to eat an apple with the skin, etc. Can chemistry help to answer these questions? 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

But 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 - hydrolysis (decomposition of the substance with water).

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

Vegetables, fruits, berries.

Why are people so fond of vegetables, fruits and berries? That is because, firstly, they are delicious, and secondly because they are useful because of their content of easily digestible carbohydrates, vitamins and minerals. Therefore, the absence in the diet of vegetables and fruit reduces the body's resistance to infection, reducing the capacity of the human and taking away a good mood.
The beneficial effect of these products on the digestive process begins in the oral cavity. The fruits of many plants affect the nerves of the mucous membrane, thereby enhanced the work of the gastrointestinal tract, stimulating the appetite.
Of particular note is the role of fiber and pectin fruits and vegetables. The human body is not able to fully digest cellulose. Therefore, it passes through the intestine, and increases peristalsis.
Pectin promotes excretion of metals, including radioactive ones. This is due to the ability of pectin with many metals to form insoluble compounds which are not digested in the digestive tract. Furthermore, pectin is used in the treatment of diseases of the stomach, as they have antibacterial properties.
Vegetables, fruits, berries and their products cannot replace animal products. Therefore, in any form - fresh, dried, canned or processed to juice - they should definitely be included in the diet.



• From what vegetables do you usually make salads at home?

• Do you like French fries? How do you prefer them cooked?
Fruits and berries

And what are the fruits and berries?

Fruits (lat. Fructus - fruit) are juicy edible garden stuff from cultivated and wild plants. Berry (lat. Bácca, úva) is a type of fetal plant. Fruits are divided into two forms: dry and juicy. Juicy fruit is a juicy pericarp (what we call pulp). There are one or several seeds inside. It is for this reason, juicy fruits fall into the category of fruit with a seed-bone and those who have a lot of seeds. So berries are something that have a juicy pulp and many seeds that are inside the hull.
There are many berry-type fruits in nature. All are classified into the following groups:
• berry (the fruits of cranberries, blueberries, cranberries, currants, grapes, gooseberry, tomato);
• apple (fruit of apple, pear, mountain ash, and others);
• melon (fruit squash, eggplant, zucchini, watermelon, melon);
• hesperides, or bitter orange (citrus fruits);
• granatina (pomegranate).
All of these plants are true berry.
But the fruit of raspberries and blackberries should not be confused with berries. They do not have the seeds, but instead, tiny bones (drupes) fused into one complex fruit - polydrupes.
Paradoxically, despite the juicy flesh and a large number of seeds, the strawberry also is not considered as a berry. The fact that the seeds of these plants are not located inside and on the surface of the fruit, and in fact they are microscopic nuts. These are called false fruit berries. Rosehip is also a false berry, but the nuts are not outside, but inside the hull.
Now you know what a berry is, and why biologists and ordinary people understand this word differently.

Let's talk about the juice.
Juice - is a drink that is produced from a variety of fruits, berries and vegetables by means of mechanical action (spinning). Juices are different: natural, fresh juices with sugar, juice with pulp or nectars, blended, dried and concentrated juices. A common opinion is that if a juice contains a lot of vitamins, then they need to be drunk a lot and often. However, even vitamins should be dispensed. Especially since the excessive abundance of juice in the diet adversely affects the pancreas. Therefore, the recommended daily norm of juice is 1 - 2 cups.

Food additives, dyes and GMOs

Visiting shops, every time we are confronted with the products on the colorful packages that the mysterious inscriptions are applied in small print. For simple buyer it is difficult to understand them. But now you are armed with this knowledge. First of all it refers to the letter "E", encrypts the product.

It turns out that eating most familiar products, such as milk, sausage, cheese, confectionery, we have eaten several kilograms of food additives for only one year.

E 100-199 - dyestuffs enhancing color of the product;

E 200-299 - preservatives that increase the shelf life of the product due to the ability to protect against germs, fungi, etc .;

E 300-399 - antioxidant, slows down the process of oxidation;

E 400-499 - stabilizers, preserving the consistency of the product;

E 500-599 - emulsifiers, promoting the formation and stabilization of emulsions;

E 600-699 - flavor enhancers and flavor;

E 700-800 - spare indexes for new possibilities of food additives;

E 900-999 - antiflaming (defoamers)

E 1000- 1999 - glazed agents.

It appeared recently on some packaging or food labels "Environmentally friendly product". They are not talking about the absence of nutritional supplements in the product, but the fact that its production process is based on the use of equipment that does not harm the environment.

Among the additives are distinguished a) non-prohibited b) dangerous c) very dangerous, and d) prohibited. A list of permitted additives for consumption is constantly adjusted.

If non-prohibited additives are used without infringement of the technology during preparation of the product, they are harmless to humans.

A significant contribution to the progress (or regress) power was genetic engineering, which has become important to develop the branch - the creation of genetically modified organisms, GMOs, to which people have an ambiguous attitude. It is believed that this is an artificial food of the modified gene transformation. However, many people do not distinguish between natural and artificial food. Perhaps GMO products will be dominant in the 22nd century. Anyway, now it is a fierce struggle between the supporters of eco-friendly products without GMOs and those who ignore all food warnings.

Obesity and Weight Loss
Many people care about their body shape and weight, considering that they need to change in one direction or another. This causes the existence of weight loss diets, for getting rid of obesity and for bringing health back to normal. Numerous studies have shown that many nutritional problems arise from the excessive consumption of fast food and sweets. However, if one considers the entire system as a whole, they can see that fashion to food is very important. Also, the body's metabolism, advertising, big business, the fertility of the soil, the organization of agriculture and progress in medicine are all equally aiding to the desirability of the food and sequentially to the over-consumption of food.

The Internet

Whomever 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 (vlogs) on YouTube.
The internet makes it possible to select all kinds of recipes. Often they are divided into simple steps - step by step recipes with illustrations. There also are 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; and,
• 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 one 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.


Find the information that you consider incorrect or contradictory.

• How do people share recipes and diets in social networks?

• How to find like-minded people or consultants?


How does the diet of an average person and an athlete differ? An athlete during training, especially in preparation for responsible competitions, requires more energy intensive foods than just a man doing morning exercises.
During the training, the athlete increases the intensity of the work of all internal organs. This requires additional energy costs.
As a rule, the diet for an athlete is selected by specialists and nutritionists using the tables. These tables indicate foodstuffs specified for the needs of their energy value and nutrient content.
To strengthen the muscle tissues, bones, ligaments and tendons, the diet includes food that supply the athletes body with protein. To increase the speed and to ensure the stable operation of the internal organs, increase the fat content in the diet. To normalize the body's energy processing, athletes need fresh fruits, vegetables and other foods rich in carbohydrates.
For the loss of water through sweat during training athletes can supplement with the use of non-carbonated mineral water, fruit juices and teas. Chocolates especially have energy properties.

The required daily calorie intake for people of different age groups of employees in different categories is portrayed in the following illustration:


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, 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 the structure of it at home. What proportion is the main course? How much would it cost if you cooked the same meal at home?


Which of the two diets above do you prefer, and why?


Why do artists love to represent the food? Perhaps because they see its abundance on holidays or are often hungry. After all, somewhere there is a saying that in order to paint a masterpiece, "the artist must be hungry."
The most impressive fine arts 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, 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 - 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 to its full, beyond recognition, which connects the latest technology, molecular chemistry and … food.

The creators of molecular cuisine - French chemists and gastronomists Paul Bocuse, Alain and Pierre Chapelle Truagroi became the founders of the latest culinary trends.
The kitchen, 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 lays out the "molecules." The most striking examples are as follows: A certain liquid solidifies into dough; meat becomes marshmallows; olive oil converts into caramel; and, 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.
To date, 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.


The End