What Is Diabetes? From Sweet Urine to Blood Sugar and Insulin

You may recognise the feeling: you pay attention to what you eat, keep an eye on your sugar intake — and still wonder whether your blood sugar is actually within a healthy range.

Diabetes is now so common in health conversations that almost everyone feels they know something about it. Yet the basic question — what is diabetes, and what actually happens in the body? — often remains unanswered.

In this article, we explain it clearly. No unnecessary jargon — just enough detail to understand what is happening in the body.

Diabetes may sound like a modern lifestyle disease, but it has been recognised for thousands of years.

Long before blood glucose meters, laboratory tests or a clear understanding of metabolism existed, doctors described people who were unusually thirsty, urinated very frequently and became progressively weaker.

As early as around 1500 BC, ancient Egyptian texts described a condition involving unusually large amounts of urine. Later, doctors noticed something even more remarkable: in some patients, the urine tasted sweet.

And yes… at the time, it was sometimes literally tasted.

Not a diagnostic method we would recommend today. 😉

But the observation pointed in the right direction.

Why is it called diabetes mellitus?

The word diabetes comes from a Greek term meaning something like “to pass through” or “siphon”, referring to the large amounts of fluid people drank and passed.

Mellitus means something close to “honey-sweet”.

Together, the name describes two features doctors recognised centuries ago: frequent urination and sugar in the urine.

What they could not yet see was what was happening in the blood.

For that, we need to jump forward a few centuries.

The discovery that changed diabetes forever

By the end of the nineteenth century, researchers had discovered that the pancreas played a crucial role in diabetes.

In 1889, Oskar Minkowski and Joseph von Mering observed that dogs developed severe diabetes after the pancreas was removed.

There had to be something in the pancreas that was essential for regulating blood sugar.

The major breakthrough came in 1921.

Canadian doctor Frederick Banting and medical student Charles Best experimented with extracts from the pancreas. Together with biochemist James Collip, they were able to purify the active substance sufficiently.

We now know that substance as insulin.

In January 1922, 14-year-old Leonard Thompson, who was severely ill with diabetes, received one of the first successful treatments with purified insulin.

What does insulin actually do?

To understand diabetes, we first need to look at blood sugar.

When you eat carbohydrates — from foods such as bread, pasta, rice, fruit or potatoes — much of them are broken down during digestion into glucose.

That glucose enters the bloodstream.

The body can use glucose as a source of energy, but it first needs to move from the blood into the cells.

That is where insulin comes in.

Insulin is a hormone produced by the pancreas. You can think of it as a key that helps glucose move from the blood into the cells.

In diabetes, this system no longer works as it should.

In type 1 diabetes, the pancreas produces little or no insulin because the immune system has attacked the insulin-producing cells.

In type 2 diabetes, the problem is different: the body becomes less responsive to insulin. This is called insulin resistance.

At first, the pancreas compensates by producing more insulin. That can work for a long time. But as the cells become increasingly resistant and the pancreas can no longer keep up with demand, the amount of glucose in the blood begins to rise.

Prediabetes can develop first — an intermediate stage in which blood sugar is already higher than normal but the criteria for type 2 diabetes have not yet been met. Over time, type 2 diabetes can develop.

Which foods raise blood sugar? → Low-sugar snacks & products →

Diabetes and our modern environment

Diabetes has therefore existed for thousands of years.

What has changed is how common it has become.

Type 2 diabetes in particular has increased sharply worldwide in recent decades. According to the World Health Organization, the number of people living with diabetes worldwide rose from around 200 million in 1990 to 830 million in 2022.

The International Diabetes Federation estimated that around 589 million adults aged 20 to 79 were living with diabetes in 2024.

Diabetes is therefore a growing global health challenge.

Blaming one single food, however, would be far too simplistic.

Our genetic make-up has not changed within a few decades. Our environment has.

On average, we move less, sit more, have constant access to energy-dense foods and eat more highly processed products. At the same time, sleep, stress, body weight, social circumstances and genetic factors all play a role.

Type 2 diabetes therefore cannot be reduced to: “You ate too much sugar.”

The relationship is much more complex.

Who is at higher risk of type 2 diabetes?

Not everyone has the same level of risk.

Factors that can play a role include:

• a family history of diabetes
• overweight, particularly excess fat around the abdomen
• low levels of physical activity
• older age
• a history of gestational diabetes
• PCOS (polycystic ovary syndrome)
• prediabetes
• certain genetic factors

Some factors cannot be changed — you do not choose your age or genetic predisposition.

Others can be influenced.

And that is where things become interesting.

Why is persistently high blood sugar a problem?

A temporary rise in blood sugar after a meal is completely normal. The body is designed to process glucose in the bloodstream.

The problem begins when blood sugar remains too high over a longer period of time.

Over time, this can damage small and large blood vessels as well as nerves. Diabetes can therefore affect different parts of the body:

• the nerves — including diabetic neuropathy
• the blood vessels in the eyes, which can affect vision
• the kidneys
• the heart and blood vessels
• the feet and legs

Diabetes also increases the risk of cardiovascular disease and stroke.

Can type 2 diabetes be prevented?

Not every form of diabetes can be prevented.

Type 1 diabetes cannot be prevented by changing your diet.

Type 2 is different. In people at increased risk, lifestyle changes can help delay the development of type 2 diabetes and, in some cases, help prevent it.

You do not need to eat perfectly from one day to the next. A few basic principles can already make a meaningful difference.

1. Build a balanced meal instead of simply cutting carbohydrates

Carbohydrates are not automatically bad. Vegetables, pulses, fruit, whole grains and dairy products also contain carbohydrates.

What matters more is which carbohydrates you choose, how much you eat and what you combine them with.

A meal containing carbohydrates together with enough protein, fibre and healthy fats is digested differently from a meal made up mainly of rapidly absorbed carbohydrates.

Compare, for example, a white bread roll with jam and fruit juice with wholegrain bread, egg, vegetables and avocado. Both meals contain carbohydrates, but their overall composition is very different.

2. Pay attention not only to what you eat, but also how much

Even nutritious foods can provide a lot of energy in large portions. You do not need to obsessively count every gram of carbohydrate — but being aware of portion sizes can help.

The goal is not to become afraid of food. It is to learn what portion size and combination work well for you.

3. Choose foods that bring more to the meal

Vegetables, fruit, nuts, seeds, pulses, fish, eggs and wholegrain foods provide more than energy: they also supply vitamins, minerals, protein and fibre.

For blood sugar, fibre is particularly interesting because it supports satiety and can help slow the absorption of carbohydrates.

4. Move your body — and don’t underestimate walking

Physical activity has an important effect on blood sugar. When your muscles are active, they use glucose from the bloodstream. Regular activity can also improve insulin sensitivity, meaning the body responds more efficiently to the insulin it produces.

A brisk walk counts. Walking the dog counts. Taking the stairs counts. Gardening counts.

Your muscles play an important role in glucose metabolism — not just in burning calories.

5. Make healthy eating easier for yourself

This is talked about surprisingly little.

You can know exactly what healthy eating looks like and still struggle to do it every day. Why? Because knowledge alone is often not enough at 6:30 pm when you arrive home tired and hungry.

Wash and chop vegetables in advance. Prepare a healthy lunch. Freeze a nourishing soup. Keep eggs and a few basic ingredients at home.

That changes something important: you do not have to rely on willpower every single time. You have simply made the healthier choice easier.

It’s not about eating perfectly

Perhaps that is the most important message of all.

Healthy blood sugar is not determined by one biscuit, one plate of pasta or dessert on a Saturday evening. What matters is the pattern that repeats itself over days, weeks and years.

How do you eat most of the time? Do you move enough? Are you getting enough fibre? How large are your portions? Are you sleeping enough?

Those questions are far more useful than trying to label one single food as “good” or “bad”.

And what about sugar?

That is exactly what we explore in our next article. Few nutrition topics are surrounded by as much confusion as sugar.

Are “natural sugars” better? Which products contain surprisingly high amounts of sugar? And which foods are worth limiting if you want to keep blood sugar more stable?

Read: Foods that raise blood sugar →