Diabetes mellitus ("sugar disease") is a group of metabolic diseases whose common feature is a chronically elevated blood sugar level (hyperglycemia). Insulin — a hormone of the pancreas — generally ensures that sugar (glucose) gets from the blood into the body's cells, where it is used as energy. With diabetes, this mechanism does not work properly: either little or no insulin is produced (type 1) or the cells no longer respond to it sufficiently (type 2).
The result: glucose accumulates in the blood, while the cells "starve" at the same time. A permanently elevated blood sugar can gradually damage blood vessels, nerves and organs — often over years, before noticeable symptoms occur.
In Germany, the prevalence of a known diabetes was, according to the Robert Koch Institute (2024 analysis), around 10.3% of adults. The prevalence has increased considerably over the past decades.¹˒²
2. Type 1 vs. type 2 — the differences at a glance
Type 1Autoimmune disease
The immune system destroys the beta cells of the pancreas
An absolute insulin deficiency — generally little or no own insulin
Onset usually in childhood/adolescence; in principle possible at any age
NOT caused by lifestyle
Generally a lifelong insulin therapy required
Modern therapy: CGM and AID systems (hybrid closed loop)
The core difference
With type 1, insulin is generally completely lacking (autoimmune). With type 2, there is usually still enough insulin present, but the cells no longer respond to it sufficiently. Type 1 is NOT caused by lifestyle and can NOT be treated by a change in lifestyle alone — an insulin therapy is generally indispensable.
3. Other forms of diabetes
Gestational diabetes: First detected during pregnancy — generally resolves again after the birth. Care always closely supervised by the treating doctors.
LADA (Latent Autoimmune Diabetes in Adults): An autoimmune form in adulthood, often initially confused with type 2. Typical: mostly slim patients without pronounced insulin resistance, with detectable autoantibodies. Over the course, an insulin therapy generally becomes necessary.
MODY (Maturity Onset Diabetes of the Young): A genetically determined form, usually beginning before the age of 25. Several subtypes with different treatments.
Secondary diabetes: Triggered by other diseases (e.g. inflammation of the pancreas, Cushing's syndrome, cystic fibrosis) or certain medications (e.g. cortisone, some antipsychotics).
Many people with type 2 have no clear symptoms for a long time
Often the diabetes is only discovered during routine examinations — or when complications have already occurred. Therefore: from about the mid-30s, have your blood sugar checked at the health check-up.
5. Diagnosis: which values are decisive?
The diagnosis is generally made via defined laboratory values. For a reliable diagnosis, according to the current NVL, two pathological laboratory values are mostly required.³
Fasting blood sugar ≥ 126 mg/dl (7.0 mmol/l) — generally confirmed on two different days
HbA1c ≥ 6.5% (48 mmol/mol) — the "long-term blood sugar" of the past 2–3 months
OGTT 2-hour value ≥ 200 mg/dl (11.1 mmol/l)
Random blood sugar ≥ 200 mg/dl with typical symptoms at the same time
Type 1 or type 2? Differentiation
Autoantibodies (e.g. GAD-AB, IA-2-AB, ZnT8-AB) — mostly positive with type 1, negative with type 2
C-peptide — low with type 1 (hardly any own insulin), normal/elevated with type 2
Clinical picture: age, BMI, family history and course (acute vs. gradual)
Do not overlook LADA
In adults, LADA (autoimmune diabetes in adulthood) is often initially misinterpreted as type 2. An autoantibody determination can be sensible in slim patients without a family history.
A combination of a long-acting basal insulin (e.g. insulin glargine or degludec) and a short-acting bolus insulin at meals (e.g. insulin lispro or aspart). Requires regular blood sugar measurement, an estimation of the carbohydrates and an individually adjusted dose calculation — together with the diabetes team.
Option 2Insulin pump + CGM + AID system (hybrid closed loop)
An insulin pump delivers insulin continuously, a CGM sensor captures the sugar value at short intervals. AID systems partly automatically adjust the insulin delivery to the current glucose value. Studies often show a better metabolic situation and fewer severe episodes of low blood sugar compared with a purely manual therapy.⁴
Type 2 diabetes is generally treated stepwise — first with an adjustment of lifestyle, then if needed with medications. Which medications make sense in an individual case is always decided by the treating doctor on the basis of the current NVL.³
Stage 0Lifestyle — the first step
A change in diet (e.g. Mediterranean, fiber-rich), regular exercise and moderate weight loss. In the first years of the disease, a remission is even possible in individual cases. A lifestyle intervention with prediabetes can considerably lower the risk of a type 2 diabetes.
Stage 1Metformin — first-choice standard therapy
Considered the standard therapy for decades. Inhibits, among other things, the sugar production of the liver and improves insulin sensitivity. Generally does not cause low blood sugar. A gradual introduction and intake with meals are often recommended in order to reduce gastrointestinal complaints.
SGLT2 inhibitors (e.g. empagliflozin, dapagliflozin) have shown additional favorable effects on the heart and kidneys in studies. GLP-1 receptor agonists (e.g. semaglutide/Ozempic, tirzepatide/Mounjaro) lower the blood sugar considerably and can at the same time contribute to weight loss and a cardiovascular benefit in certain patient groups. In people with relevant heart or kidney diseases, their use can, according to the guideline, also be sensible early on.³
Stage 3Insulin — when other options are not sufficient
When oral medications and GLP-1 receptor agonists are not sufficient, a basal insulin is often added. The transition to insulin is mostly not a "failure" of the therapy, but reflects the natural course of the disease.
Cardiovascular — a considerably increased risk of heart attack and stroke; blood pressure and blood lipids should be well controlled
Diabetic foot syndrome — a daily inspection of the feet is recommended
Depression — more common in people with diabetes than in the general population
Gum diseases (periodontitis) — regular dental check-ups important
Prevention schedule
Quarterly: HbA1c, blood pressure, a check of the feet
Annually: An eye examination, kidney values, blood lipids, a structured foot examination, a cardiovascular assessment
DMP diabetes — a structured education program and regular checks; enrollment with the health insurance
9. Living with diabetes
Diet: A special "diabetic diet" is generally not necessary. A balanced, fiber-rich diet with little sugar and sweet drinks is mostly recommended. With type 1, estimating carbohydrates is generally mandatory, with type 2 often helpful.
Sport: Regular exercise is generally recommended with both forms of diabetes. It mostly improves insulin sensitivity (important with type 2) and can help keep the blood sugar more stable.
Alcohol: With the intake of insulin or sulfonylureas, alcohol can increase the risk of low blood sugar. More: Medications and alcohol.
Travel: Insulin generally has to be transported cool; a sufficient reserve and a medical certificate for syringes, a pump or CGM in hand luggage are sensible. More: Medications when travelling.
Emergency: low blood sugar (hypoglycemia)
Typical warning signs: trembling, sweating, a racing heart, ravenous hunger, irritability. Immediate measure: take fast-acting carbohydrates (e.g. glucose), then measure again. In severe cases with unconsciousness: call 112 (in the US: 911) — and if trained, use the glucagon emergency medication.
How brite helps you with diabetes
brite brings structure to your diabetes therapy — whether type 1, type 2 or another form of diabetes.
Intake reminder — metformin, insulin, a weekly GLP-1 injection or a sensor change: brite reminds you reliably. Set up a reminder
Interaction check — check diabetes medications in combination with blood pressure reducers, statins or painkillers. Check now
Health history — document blood sugar, HbA1c, weight and blood pressure over time. Track your history
Digital medication plan — all medications clearly organized for diabetologists, GP and pharmacy. Go to medication plan
Type 1 is an autoimmune disease — generally no own insulin is produced anymore, and a lifelong insulin therapy is needed. Type 2 is mostly characterized by insulin resistance, often in combination with overweight. Here the treatment begins with lifestyle, then medications such as metformin, SGLT2 inhibitors or GLP-1 receptor agonists are added; insulin often becomes necessary only in later stages.
Type 1 is not curable according to current knowledge — an insulin therapy is generally required for life. With type 2, a remission can be possible, especially through weight loss and a change in lifestyle in the first years of the disease. Remissions are also described after bariatric surgery. There is, however, a risk of relapse.³
Fasting blood sugar normally below 100 mg/dl (5.6 mmol/l); HbA1c below 5.7%. Prediabetes is mostly considered a fasting blood sugar between 100 and 125 mg/dl or HbA1c 5.7–6.4%. The diagnosis of diabetes is generally made from a fasting blood sugar ≥ 126 mg/dl or HbA1c ≥ 6.5%.³
It is generally not that simple. Type 1 has nothing to do with diet, but is an autoimmune disease. With type 2, overweight plays a big role — and sugar can contribute to it. But genetics, lack of exercise, highly processed foods and social factors are also relevant.
The HbA1c reflects the average blood sugar of the past two to three months. A value below 5.7% is generally considered normal. From about 6.5% it is classified as a diabetes criterion. An advantage: the measurement is not tied to fasting.³
Both are GLP-1 receptor agonists used with type 2 diabetes. They can lower the blood sugar considerably, influence the appetite and lead to weight loss in some of those treated. Ozempic contains semaglutide, Mounjaro tirzepatide. With type 2 diabetes, they are generally covered by the statutory health insurance funds in Germany.
CGM stands for continuous glucose monitoring. A small sensor under the skin measures the sugar value at short intervals and generally transmits it to a smartphone or receiving device. CGMs are considered the standard with type 1 diabetes today and are increasingly also used with type 2 under insulin therapy.
With warning signs, immediately take fast-acting carbohydrates (e.g. glucose or a sugary drink) and measure again after a few minutes. In severe cases with clouded consciousness or unconsciousness: call 112 (in the US: 911) — and if trained, use the glucagon emergency medication. Never give anything to an unconscious person.
A type 1 diabetes cannot currently be reliably prevented. With type 2 diabetes, the risk is influenceable in many cases: maintaining a normal weight, regular exercise, a balanced diet and not smoking are considered important building blocks. Studies on lifestyle intervention with prediabetes have shown that the risk of a type 2 diabetes can be considerably lowered.
Medical disclaimer: This article is for general information and does not replace medical advice, diagnosis or treatment. Dosages, the choice of medication and treatment goals are always determined individually by the treating doctor. With suspicion of ketoacidosis (e.g. fruity-sweet breath odor, vomiting, disturbances of consciousness) or with a severe low blood sugar, call 112 (in the US: 911) immediately. Diabetes medications should not be stopped on one's own. Last updated: April 2026.
