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Diabetes Explained: Causes, Types, Reversal and Complications
What diabetes is, why it happens, and what it can lead to
A clear overview of types, causes, reversal and complications.
Diabetes is a condition where blood sugar stays higher than normal because the body either doesn't make enough insulin or can't use it well. The main types are type 1, type 2, gestational and prediabetes. Type 2 and prediabetes can often be improved — and sometimes put into remission — with lifestyle changes, while type 1 always requires insulin.
What It Means
Insulin is a hormone that helps move sugar (glucose) from your blood into your cells for energy. In diabetes, that system breaks down — either because the body stops making enough insulin or because cells stop responding to it — so sugar builds up in the blood.
Why It Matters
High blood sugar over years can quietly damage blood vessels and nerves throughout the body. Catching it early gives you the best chance to slow, stop or even reverse that damage.
What Is Normal
A fasting blood glucose under 100 mg/dL and an HbA1c below 5.7% are generally considered normal for adults. 5.7–6.4% suggests prediabetes; 6.5% or higher generally meets the threshold for diabetes.
When To Pay Attention
Frequent thirst, frequent urination, unexplained weight changes, blurry vision, slow-healing cuts or constant fatigue can all be early signals worth discussing with your doctor — especially alongside an HbA1c in the prediabetes or diabetes range.
Common questions
What causes diabetes?
Type 1 is an autoimmune condition where the body stops making insulin and is not caused by lifestyle. Type 2 develops when the body becomes resistant to insulin and/or doesn't make enough — risk factors include genetics, excess weight (especially around the abdomen), inactivity, poor sleep, certain medications and age. Gestational diabetes appears during pregnancy due to hormonal changes.
What are the types of diabetes?
The main types are: type 1 (autoimmune, usually diagnosed earlier in life, always needs insulin), type 2 (the most common, driven by insulin resistance), gestational (during pregnancy, often resolves after birth), and prediabetes (blood sugar higher than normal but not yet in the diabetes range).
Can diabetes be reversed?
Type 2 diabetes can often be put into remission — meaning HbA1c stays in the normal range without diabetes medication — through significant changes to diet, weight, activity and sleep, sometimes supported by medical care. Prediabetes can frequently be reversed. Type 1 diabetes cannot be reversed and always requires insulin.
What conditions can follow if diabetes isn't managed?
Long-standing high blood sugar can contribute to heart disease and stroke, kidney disease, nerve damage (neuropathy), eye problems including diabetic retinopathy, foot ulcers and infections, fatty liver disease and an increased risk of certain dementias. Good control significantly lowers these risks.