What is diabetes?

What is Diabetes?

Diabetes is a metabolic disease where your blood sugar stays too high because your body either doesn't make enough insulin, can't use insulin properly, or both. 1

The Basic Problem

Diabetes fundamentally involves a breakdown in how your body handles sugar (glucose). Normally, insulin—a hormone made by your pancreas—acts like a key that unlocks your cells so glucose can enter and provide energy. In diabetes, this system fails. 1, 2

The core issue is chronic hyperglycemia (high blood sugar) resulting from defects in insulin secretion, insulin action, or both. 1, 3

The Two Main Types

Type 1 Diabetes (5-10% of cases)

• Your immune system mistakenly attacks and destroys the insulin-producing cells (β-cells) in your pancreas. 1, 3
• This creates an absolute insulin deficiency—your body makes little to no insulin at all. 1, 4
• Without insulin treatment, you can develop diabetic ketoacidosis within hours, which is life-threatening. 1, 4
• Most commonly starts in childhood or adolescence, but can occur at any age. 1
• These patients always require insulin injections to survive. 3

Type 2 Diabetes (90% of cases)

• Your body becomes resistant to insulin's effects, and your pancreas can't make enough insulin to overcome this resistance. 1, 3
• This is a combination problem: insulin resistance plus inadequate insulin production. 1, 2
• Often develops gradually and may go undetected for years. 1
• Strongly linked to obesity, physical inactivity, and genetic factors. 1, 3
• Initially may be managed with lifestyle changes and pills, but many eventually need insulin. 1, 3

What Happens in Your Body

When insulin doesn't work properly:

• Glucose can't enter your cells, so it builds up in your bloodstream instead. 2
• Your cells are starved for energy despite high blood sugar. 2
• Your body breaks down fat and protein for fuel, creating harmful byproducts. 1, 2
• This disrupts how your body processes carbohydrates, fats, and proteins. 1, 5

Common Symptoms

The classic warning signs include:

• Excessive thirst and frequent urination (polyuria, polydipsia) 1, 3
• Unexplained weight loss despite eating normally 1, 2
• Increased hunger 1
• Blurred vision 1
• Fatigue and weakness 5

Important caveat: Type 2 diabetes often has no symptoms initially, which is why screening is crucial. 3

How It's Diagnosed

You have diabetes if any of these apply:

• Fasting blood sugar ≥126 mg/dL on two separate occasions 1, 3
• Random blood sugar ≥200 mg/dL with classic symptoms 1, 6
• 2-hour blood sugar ≥200 mg/dL after drinking a glucose solution (oral glucose tolerance test) 1, 3
• Hemoglobin A1c ≥6.5% (a measure of average blood sugar over 2-3 months) 1, 3

Long-Term Complications

Chronic high blood sugar damages blood vessels and nerves throughout your body:

Microvascular (small blood vessel) complications:

• Retinopathy: eye damage that can cause blindness 1, 3
• Nephropathy: kidney damage leading to kidney failure 1, 3
• Neuropathy: nerve damage causing pain, numbness, and foot ulcers 1, 3

Macrovascular (large blood vessel) complications:

• Heart disease and heart attacks 1, 3
• Stroke 1
• Peripheral arterial disease (poor circulation to legs) 1

Critical Pitfalls to Avoid

• Missing the diagnosis: Type 2 diabetes can be silent for years while causing damage. Regular screening is essential for at-risk individuals. 3
• Delaying insulin in Type 1: Failure to recognize absolute insulin deficiency leads to diabetic ketoacidosis, which can be fatal. 4, 2
• Focusing only on fasting blood sugar: Post-meal (postprandial) hyperglycemia is often the first abnormality and shouldn't be ignored. 3
• Misclassifying diabetes type: This leads to inappropriate treatment—Type 1 patients need insulin immediately, not pills. 3

The Bottom Line

Diabetes is fundamentally about your body's inability to properly regulate blood sugar due to insulin problems. Type 1 is an autoimmune destruction requiring lifelong insulin. Type 2 is a progressive condition of insulin resistance and declining insulin production, often preventable or manageable with lifestyle changes initially. Both types, if uncontrolled, lead to serious complications affecting your eyes, kidneys, nerves, heart, and blood vessels. 1, 2, 3