Diabetes: Types, Symptoms, Tests & Management

Diabetes mellitus

Introduction

Diabetes is one of the most common chronic diseases in the world. It often develops slowly and unnoticed – especially type 2 diabetes – and is only discovered when symptoms appear or a routine blood test shows raised values. Untreated, high blood sugar damages blood vessels, nerves and organs over time.

The good news: diabetes can be managed well, and type 2 diabetes in particular can be significantly improved through lifestyle changes – sometimes to the point of remission. This guide explains the different types, the warning signs, the most important tests and what you can do every day.

What exactly is diabetes?

Glucose is the main fuel for the body’s cells – from the brain to the muscles. For glucose to get from the blood into the cells, the body needs insulin, a hormone produced by the beta cells of the pancreas. Insulin works like a key that opens the cells to glucose.

In diabetes, this system is disrupted. Either the pancreas produces too little or no insulin (type 1 diabetes), or the cells respond less and less to it (insulin resistance in type 2 diabetes). Glucose then builds up in the blood.

Over time, high blood sugar damages small and large blood vessels and nerves. That is why diabetes is not just a “sugar problem”, but a major risk factor for heart attack, stroke, kidney disease, vision loss and foot problems.

What are the types of diabetes?

Type 1 diabetes

An autoimmune disease in which the immune system destroys the insulin-producing beta cells. It often starts in childhood or adolescence, but can occur at any age. People with type 1 diabetes need insulin for life. Symptoms often develop quickly, within days or weeks.

Type 2 diabetes

The most common form, accounting for about 90% of cases. At first, the pancreas still produces insulin, but the cells respond less well to it (insulin resistance). Over time, insulin production also declines. Type 2 diabetes develops over years and often causes no symptoms for a long time. Risk factors include excess weight (especially around the abdomen), lack of exercise, family history, age and certain ethnic backgrounds – but people of normal weight can also be affected.

Gestational diabetes

Diabetes that first appears during pregnancy. It usually disappears after birth, but increases the risk of type 2 diabetes later in life for both mother and child. Pregnant women are routinely screened for it.

Other types

Monogenic diabetes (e.g. MODY, neonatal diabetes): caused by a change in a single gene
Secondary diabetes: caused by other diseases (e.g. pancreatitis, cystic fibrosis, Cushing’s syndrome) or medications (e.g. cortisone)

Knowing which type you have is important, because the treatment differs considerably.

Less common forms

LADA – autoimmune diabetes in adults

LADA (latent autoimmune diabetes in adults) is an autoimmune form like type 1, but develops slowly in adults. It is often initially mistaken for type 2 diabetes. Typical signs are that diet and tablets stop working well after a short time, and the person is often not overweight. Antibody tests can clarify the diagnosis. People with LADA usually need insulin sooner than people with type 2 diabetes.

MODY – inherited diabetes

MODY (maturity-onset diabetes of the young) is a rare genetic form that usually appears in adolescence or young adulthood. It is not autoimmune. Depending on the subtype, some forms need hardly any treatment, others respond very well to certain tablets, and some need insulin. Genetic testing may be useful if diabetes occurs in several generations of a family, especially in slim, young people.

Symptoms that are easy to miss

The symptoms of diabetes are often mistaken for stress, tiredness or aging:

increased thirst
frequent urination, especially at night
increased hunger, sometimes with unintended weight loss
tiredness and lack of energy
blurred vision
itchy skin and frequent infections, e.g. fungal or urinary tract infections
slow wound healing
tingling or numbness in the feet

Many people with type 2 diabetes have no symptoms at all for years. That is why regular check-ups are important, especially if you have risk factors.

Which tests detect diabetes and prediabetes?

Diabetes is diagnosed using these tests:

HbA1c (average blood sugar over the past two to three months): 6.5% or higher indicates diabetes, 5.7–6.4% prediabetes
fasting blood glucose: 126 mg/dL (7.0 mmol/L) or higher indicates diabetes
oral glucose tolerance test (OGTT): 200 mg/dL (11.1 mmol/L) or higher after two hours indicates diabetes
random blood glucose of 200 mg/dL or higher with typical symptoms

Depending on the situation, your doctor may also order:

autoantibodies and C-peptide to distinguish between type 1, LADA and type 2,
blood lipids, kidney values and a urine test for protein,
eye and foot examinations to detect complications early.

Fasting insulin and the HOMA-IR index can provide information about insulin resistance, but are not used to diagnose diabetes. Blood pressure, weight and waist circumference should also be checked regularly.

What should a diabetes-friendly diet look like?

There is no single “diabetes diet”. Several eating patterns – such as the Mediterranean diet, low-carbohydrate diets or plant-based diets – can work well. What they have in common:

Recommended foods:

vegetables, especially leafy greens, broccoli, pumpkin and zucchini
whole grains such as oats, buckwheat, quinoa and wholemeal bread
legumes such as lentils, chickpeas and beans
nuts and seeds
healthy fats such as olive oil, avocado and oily fish
berries and other whole fruit in moderate amounts

Foods to limit:

sugar in all forms – white, brown, coconut sugar and syrups all raise blood sugar
white bread, white rice and other refined grains
sugary drinks and fruit juices
fast food and highly processed foods

Fiber-rich foods with a low glycemic index cause a slower rise in blood sugar. Whether you eat three or five meals a day matters less than what and how much you eat. If you take insulin or certain tablets, discuss your meal pattern with your diabetes team.

Can type 2 diabetes be reversed?

Many people with type 2 diabetes can achieve remission – blood sugar levels in the normal range without diabetes medication. In the British DiRECT study, almost half of the participants who followed an intensive weight-loss program were in remission after one year. The chances are best when diabetes has been diagnosed recently.

The most important steps:

losing excess weight – often 10–15 kg makes a big difference
changing your diet
regular physical activity
reducing stress
getting enough sleep

Remission is not a cure: if the weight comes back, blood sugar usually rises again. Regular check-ups remain important. Never stop or change your medication without talking to your doctor.

Managing diabetes day to day

Living with diabetes takes planning and patience. Useful tools:

regular blood glucose monitoring – with a meter or a continuous glucose monitor (CGM)
a food and activity diary
planned shopping and meals
reading food labels
diabetes education courses
support from family, friends or self-help groups

Many people find it helpful to see diabetes not as a punishment, but as a reason to take better care of themselves.

Do sleep and the body clock affect blood sugar?

Yes. Lack of sleep increases stress hormones and appetite and worsens insulin sensitivity – even a few nights of poor sleep can measurably raise blood sugar. Untreated sleep apnea is also common in type 2 diabetes and worsens blood sugar control.

What helps:

7–9 hours of sleep a night
less screen time before bed
dinner two to three hours before bedtime
regular sleep and wake times

Does a plant-based diet help?

A well-planned plant-based diet can improve insulin sensitivity, blood sugar and weight. It provides plenty of fiber and phytonutrients. The key is whole foods – vegetables, legumes, whole grains, nuts and fruit – not processed vegan products. People who eat a strictly vegan diet need vitamin B12 supplements, which is particularly important for people taking metformin, as it can also lower B12 levels.

Can you exercise with diabetes?

Yes – and it is strongly recommended. Exercise lowers blood sugar and improves insulin sensitivity for up to 48 hours.

Good options:

walking, Nordic walking
yoga, Pilates
swimming, cycling
strength training, which builds muscle that takes up glucose

A 10–15-minute walk after meals noticeably lowers the rise in blood sugar. If you take insulin or certain tablets, check your blood sugar before and after exercise and carry fast-acting sugar with you, as exercise can cause hypoglycemia.

Living well with diabetes

A diagnosis can be a shock. Many people go through phases of worry, frustration or even depression – this is common, and it is important to talk about it. Diabetes distress and depression are treatable.

What helps:

accepting the diagnosis
learning about the disease – knowledge gives you control
celebrating small successes
being kind to yourself on difficult days

How does stress affect blood sugar?

Stress hormones such as cortisol and adrenaline raise blood sugar. Chronic stress can make blood sugar harder to control and makes it harder to stick to healthy habits.

What helps:

meditation, breathing exercises and relaxation techniques
time in nature
social contact and laughter

Do herbs and supplements help?

Some herbs and supplements can lower blood sugar slightly, but they do not replace treatment:

white mulberry leaf – may slow the absorption of sugar
berberine – lowers blood sugar in several studies; interacts with many medications
fenugreek – may improve blood sugar levels
Ceylon cinnamon – modest effect on blood sugar

Combined with diabetes medication, especially insulin or sulfonylureas, they can cause hypoglycemia. Always talk to your doctor before taking supplements.

Can children get diabetes?

Yes. Type 1 diabetes is the most common form in children and adolescents, and type 2 diabetes is also becoming more common in young people with obesity. Type 1 diabetes cannot be prevented and is not caused by eating too many sweets.

Children with diabetes can lead full lives: they can play sports, go on school trips, eat ice cream with the right insulin dose, and pursue any career they want. With good training, many children learn to manage their diabetes very well.

Warning signs of diabetes in children:

Sudden, intense thirst – your child may drink liters of water a day
Frequent urination, including at night – or bedwetting in a child who was already dry
Noticeable tiredness and lack of energy
Weight loss, despite a normal or increased appetite
Irritability, concentration problems, mood swings
Recurring infections, e.g. fungal skin infections
Breath that smells fruity or of acetone, nausea, vomiting, abdominal pain or rapid breathing

Important: The last group of symptoms can indicate diabetic ketoacidosis, a life-threatening complication. If your child has these signs, go to a doctor or emergency department immediately. If you notice the other signs, have your child’s blood sugar checked the same day.

For parents, the diagnosis means a lot of learning at first: carbohydrate counting, insulin doses, glucose monitoring and communicating with school or nursery. Diabetes teams, education programs and other families can help. Over time, it becomes part of everyday life.

Final thoughts

Diabetes is not a punishment for a “wrong” diet – genes, age and many other factors play a role. But you have a lot of influence: a healthy diet, regular exercise, good sleep, stress management and close cooperation with your diabetes team can keep blood sugar in check and prevent complications. Small, consistent steps make the biggest difference.