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Written in 7th grade, part of Science Fair

There is much talking in media about that sugar is dangerous. There are a lot of articles about LCHF (Low Carb High Fat). You maybe have wondered: Is sugar dangerous? Do we need sugar? Why do we have insulin? What is diabetes? I am going to try to answer your questions.

Already in year 1550 B.C., the Egyptian hieroglyphs describe the illness diabetes (diabetes mellitus). The word diabetes comes from Greek and means "to pass through" (you pee a lot) and mellitus means “sweet as honey” because the urine tastes sweet. There are two types of diabetes. Earlier they were called “insulin-dependent” and “none insulin-dependent”. Today they are named “type 1 diabetes” and “type 2 diabetes”. I am going to write only about type 1 diabetes. Diabetes was in old days a very serious illness and people died of it. This changed when Fredrick Banting and John MacLeod discovered insulin year 1922. They got the Nobel Prize in medicine in 1923.

The body needs energy. Everything that moves needs energy, e.g. a car that drives or an airplane that flies. Computers and mobile phones need energy. We and all animals also need energy. When we are talking, running, eating, thinking or sleeping, energy is needed. Everything we do needs energy. The more demanding activities we do, the more energy is needed.
If your weight is 65kg, you use ≈ 2300 kcal/24h during normal activity. When you are running, you use around 2300 kcal/3h, i.e. that running requires much more energy.

1g Proteins



1g Carbohydrate 



1g Fat



If you easily want to solve your energy needs, you can eat a Big Mac menu (1130 kcal) + a coffee and a muffin (725 kcal)  and a Snickers (400 kcal) for dessert. Then you have got the amount of energy that you need for 24h. But if you go to McDonalds “just for fun” and eat a meal beside the ordinary food, because it tastes good, you need to run a half marathon to get rid of the extra energy. If you don’t get rid of the energy, it becomes fat.

Different energy sources
The body uses fat, carbohydrates and proteins as energy sources. Carbohydrates are the most important energy source. Carbohydrates are sugar molecules, which are connected together. When they are connected in long chains, they are called starch. When two molecules are connected (fructose and glucose) it is called sucrose (normal sugar).
Glucose (also known as grape sugar or dextrose) is a simple form of sugar, a monosaccharide (one molecule). 

Glucose (grape sugar) = C6H7O(OH)5
Fructose = C6H7O(OH)5
Sucrose (normal sugar) = C12H22O11 Starch = C6H10O5n

Glucose is one of the most important carbohydrates. It goes faster for the body to take it up than e.g. sucrose, which is a disaccharide (two molecules) or starch, which is a polysaccharide (many molecules). Starch which is in e.g. potatoes, bread, pasta and rice, is the most common carbohydrate in the food.

When you eat food, your digestive system breaks down the carbohydrates into simpler forms, with help from the enzymes. When it finally turns into glucose, it can pass into the blood. With the blood, the glucose finally reaches our cells, where it is used as energy. Sugar turns into energy through the Krebs cycle, and the end product is CO2 and water (and energy).

Constant blood glucose level
There is an unconscious body sense “blood sugar sense” which has receptors that measure how much glucose there is in blood, and keeps the glucose level fairly even, ≈ 4-7 mmol/L, corresponding to only two lumps of sugar in all our blood. One lump of sugar (3g) = 15 kcal.

     A diagram of the blood sugar level of the day, of a diabetic- and a helthy person.
     -The picture is modified from a book by Rangnar Hanås-


Insulin is the key
When we haven’t eaten for a long time, or in the morning before breakfast, the blood sugar level is low. When we have eaten, the blood sugar level is higher. The “blood sugar sense” sends information to the pancreas. There are beta cells, in the pancreas, that produce insulin. To enter the cells, the glucose needs insulin. Insulin is like small keys which “unlock" the doors to the cells so the sugar can enter. Therefore it is very important that we have insulin. Without insulin any sugar can get into the cells and the cells don’t get energy and other body functions don’t work as they should.

When there isn’t enough sugar in the cells, the body uses the sugar reserves from the liver. If there is no more sugar in the liver, the body breaks down fat and muscles instead of sugar to make energy. That produces glucose and ketones, which are used as fuel. If this continues long time, you lose weight. This applies to both healthy and people with diabetes.

Diabetes – lack of insulin
If a person has diabetes type 1, there is no insulin production. If there is no insulin, then there are no keys to “unlock” the cells. What happens if the keys are missing?
The sugar will not enter the cells, the cells don’t get energy. This means that diabetics, who have not taken insulin or have taken too little insulin, have very much sugar in their blood. Even though there is a lot of sugar the cells are starving. This because the sugar is on the wrong side of the cell wall, in the blood instead of in the cells.

When a diabetic doesn’t have energy, in the cells, for his activities (like talking, running, eating, thinking or sleeping) he becomes tired and may get headache. 

When there is a lack of sugar (energy) in the cells, the body releases even more sugar from the deposits into the blood and blood sugar levels rise even more. And even more ketones are produced. If there is too much ketones, the blood becomes acidic, and you can get ketoacidos and later diabetes coma (which is very dangerous). But before this happens the diabetics have so high blood sugar level that the kidneys can’t handle the big amount of sugar. The kidneys “leak” sugar. Some of the sugar comes out through the urine. The diabetics start to pee a lot and get extremely thirsty and start to drink a lot. 

A person with diabetes does not produce insulin and must administrate insulin from outside, in injection form, many times a day.

Balance between food and insulin
Those who don’t have diabetes have a perfect “blood sugar sense”, and get enough insulin and have perfect blood sugar level all the time. But if you have diabetes you must calculate yourself how much insulin you need. It depends on what and how much you plan to eat (amount of energy), and which physical activity you plan to do (energy consumption), as well as the blood sugar level you have currently. To know what blood sugar level you have, you take blood samples with a glucose meter several times daily. If you run or make another big effort and use up much energy you have to eat more carbohydrates and take more insulin. If a diabetic drank a half-liter Coca-Cola, he would receive over 53g of sugar, equivalent to 18 lumps of sugar. This would be a disaster since  we only have two lumps of sugar in the blood. If a non-diabetic drank the same Coca-Cola, it would not happen so much since the body corrects the glucose levels (using insulin) and the “waste sugar” is converted to fat.

A diabetic always needs a balance between food and insulin. I have told about what happens if you have too little insulin. But what happens if you have too much insulin? This can happen if you eat too little or if you take too much insulin. Than all sugar disappears into the cells and it is too little sugar left in the blood, and the blood glucose level is too low. You can become tired and get headache and if it’s very low you can get convolutions or even faint. And then it is a very serious situation. And you quickly need to get sugar or glucose. If you are not unconscious you can eat or drink something with sugar. If you are unconscious you can get a glucagon injection that quickly releases glucose from the body deposits. And maybe you need to get glucose directly into the blood in hospital.

What to do in emergency case

If a diabetic feels bad or behaves strangely, if you do not know why, you should always give sugar. If diabetic has low blood glucose he or she will be better soon. If you see a diabetic who is unconscious, you should call an ambulance.

Reason for diabetes
You get type 1 diabetes randomly, it is rare hereditary. Type 2 diabetes can however be hereditary but can also be triggered by obesity, and is therefore a completely different disease.  In type 1 diabetes pancreas does not produce any insulin, which is troublesome for the diabetics. Approximately 0,6% of the population in Sweden has type 1 diabetes.

Diabetes researchers all over the world are trying to find the reason why the insulin-producing cells die to find a cure.

Future treatment, Nano Pills

Insulin is a protein and a hormone and consists of 51 amino acids. A diabetic cannot take tablets containing insulin (nowadays), because the enzymes[1] in the stomach break down proteins.
Most diabetics use a combination of insulin that is quickly absorbed, taken shortly before a meal, and insulin that is absorbed slowly from under the skin during the whole 24h.
A group of Indian researchers have an idea for an alternative treatment to the syringes. They have managed to construct a nano tablet, which can survive the trip through the digestive system. That little pill contains insulin and if the blood sugar level is a bit too high, is the nano tablet dissolved up, and insulin is released. The idea is that people with diabetes, in the future need only swallow one pill 40 minutes before they eat.


In this essay I have answered the question "Is sugar dangerous?”. Sugar or carbohydrates are the most important source of energy, and we need it to live. But sugar can be very dangerous if you are a diabetic and do not have insulin. Sugar can also be dangerous if you eat too much sugar. You can then become overweight and may get diseases associated with overweight (e.g. type 2 diabetes or heart disease).

In order to be able to handle diabetes there has to be a balance between food and insulin.


Illustrerad Vetenskap FOKUS LIVET (nr 1) p.22-23
Illustrerad Vetenskap FOKUS MEDICIN (nr 3) p. 40-41, 51
Illustrerad Vetenskap FOKUS MÄNNISKAN (nr 6) p. 9-10, 36-37
Typ 1 Diabetes hos barn, ungdomar och unga vuxna, by R. Hanås

Thanks to Rangnar Hanås who gave me permission to use all the illustrations from his book, I have made some modifications of the illustrations.

[1]Enzymes are small things with "scissors" that cuts apart the sugar in the stomach, so it becomes easier forms.