Diabetes mellitus is a condition in which the body cannot properly control blood sugar levels. It affects over 500 million people worldwide — and millions more are living with it without knowing. In Ghana and across Africa, it is one of the fastest-growing chronic diseases, driven largely by changing diets and lifestyles. Understanding how it works, what causes it, and how to manage it could save your life.

How the Body Normally Controls Blood Sugar

Every time you eat, your digestive system breaks food down into glucose — a type of sugar that enters your bloodstream. Your blood sugar level rises. In response, the pancreas — a gland behind your stomach — releases a hormone called insulin.

Think of insulin as a key. Your cells have locks on their surface called insulin receptors. When insulin (the key) attaches to these receptors (the locks), the cell opens up and allows glucose to enter. The glucose is then used as energy to power everything your body does — breathing, thinking, walking, healing.

In diabetes, this system breaks down. Either there is not enough insulin, or the locks on the cells stop responding to the key. The result: glucose stays in the bloodstream where it does not belong, and the cells are starved of energy they cannot access.

High blood sugar does not cause pain immediately — that is what makes diabetes so dangerous. The damage builds silently over years before symptoms become obvious.

Types of Diabetes Mellitus

Type 1 Diabetes — The Immune System Attacks

In Type 1 diabetes, the body's own immune system mistakenly destroys the insulin-producing cells in the pancreas (beta cells). This is an autoimmune condition — meaning the body attacks itself. The result is little to no insulin production at all.

Type 1 is not caused by diet or lifestyle. It typically begins in childhood or young adulthood and requires insulin injections for life. Without insulin, a person with Type 1 diabetes cannot survive.

Type 2 Diabetes — Insulin Resistance

Type 2 is by far the most common form — about 90% of all diabetes cases. In Type 2, the pancreas still produces insulin, but the body's cells gradually stop responding to it properly. This is called insulin resistance.

Initially, the pancreas compensates by producing more and more insulin. Over time, it cannot keep up, and blood sugar levels rise persistently. Type 2 is strongly linked to lifestyle factors and develops over years — often silently.

Gestational Diabetes — During Pregnancy

Develops during pregnancy in women who did not previously have diabetes. Pregnancy hormones interfere with insulin signalling, causing blood sugar to rise. It usually resolves after birth but significantly increases the mother's risk of developing Type 2 diabetes later in life. It also increases risks for the baby if not managed.

Prediabetes — The Warning Stage

Blood sugar levels are higher than normal but not yet high enough to be diagnosed as Type 2 diabetes. This is the critical window — with lifestyle changes, prediabetes can be reversed completely. Without intervention, most people with prediabetes develop Type 2 diabetes within 10 years.

Symptoms — What to Watch For

Classic Symptoms of Diabetes

  • Excessive thirst — the body tries to dilute excess blood sugar by making you drink more
  • Frequent urination — especially at night; kidneys work overtime to filter out excess glucose
  • Unexplained weight loss — cells cannot access glucose so the body breaks down fat and muscle for energy
  • Constant hunger — even after eating, cells are starved because glucose cannot enter them
  • Extreme fatigue — cells are not getting the energy they need
  • Blurred vision — high blood sugar causes the lens of the eye to swell
  • Slow-healing wounds — high sugar impairs blood flow and immune function
  • Frequent infections — especially skin, urinary, and gum infections
  • Tingling or numbness in hands and feet — early nerve damage

Type 1 symptoms come on quickly — over days or weeks. Type 2 symptoms develop slowly over years. Many people with Type 2 have no symptoms at all until complications develop.

A 45-year-old man in Kumasi visits the hospital for blurred vision. He assumed it was eye strain from work. A routine blood test reveals his fasting blood sugar is 14 mmol/L — more than twice the normal level. He has had Type 2 diabetes for at least three years without knowing it. His kidneys already show early signs of damage. He had no idea.

Risk Factors for Type 2 Diabetes

Risk Factors You Cannot Change

  • Family history — having a parent or sibling with Type 2 diabetes increases your risk significantly
  • Age — risk increases after 40, though Type 2 is increasingly seen in younger people
  • Ethnicity — people of African, South Asian, and Hispanic descent are at higher risk
  • History of gestational diabetes — raises lifetime risk of Type 2 significantly
  • Polycystic ovary syndrome (PCOS) — associated with insulin resistance

Risk Factors You Can Change

  • Excess weight — particularly belly fat, which releases inflammatory chemicals that interfere with insulin signalling
  • Physical inactivity — muscles use glucose during exercise; inactive muscles become insulin resistant
  • Poor diet — high intake of refined carbohydrates, sugary drinks, and processed foods
  • Smoking — increases insulin resistance and reduces blood flow
  • Poor sleep — even one week of sleep deprivation causes measurable insulin resistance
  • Chronic stress — stress hormones (cortisol) raise blood sugar and promote fat storage around the abdomen
  • High blood pressure and high cholesterol — frequently occur alongside diabetes and worsen outcomes

Complications — Why Control Matters So Much

Persistently high blood sugar damages blood vessels and nerves throughout the body. Over years, this causes:

  • Diabetic retinopathy — damage to blood vessels in the eyes; leading cause of blindness in adults
  • Diabetic nephropathy — kidney damage; diabetes is the leading cause of kidney failure worldwide
  • Diabetic neuropathy — nerve damage causing pain, numbness, and tingling — usually starting in the feet
  • Heart disease and stroke — people with diabetes are 2 to 4 times more likely to develop cardiovascular disease
  • Diabetic foot — poor circulation and nerve damage leads to foot ulcers that heal poorly and can require amputation
  • Increased infection risk — impaired immune function makes infections more frequent and harder to treat

The good news: these complications are largely preventable with good blood sugar control.

Diagnosis — The Tests

  • Fasting plasma glucose (FPG) — blood sugar after 8 hours of not eating. Normal: below 5.6 mmol/L. Diabetes: 7.0 mmol/L or above
  • HbA1c (glycated haemoglobin) — shows average blood sugar over the past 2 to 3 months. Normal: below 5.7%. Diabetes: 6.5% or above. This is the most useful test for monitoring long-term control
  • Oral glucose tolerance test (OGTT) — blood sugar measured before and 2 hours after drinking a glucose solution
  • Random plasma glucose — blood sugar taken at any time; 11.1 mmol/L or above with symptoms indicates diabetes

Treatment

Type 1 — Insulin is Essential

People with Type 1 diabetes must take insulin every day — there is no alternative. Modern options include insulin pens, pumps, and increasingly, continuous glucose monitors that track blood sugar in real time. The goal is to mimic what a healthy pancreas does naturally — providing background insulin constantly, with extra doses at mealtimes.

Type 2 — Start with Lifestyle

For many people, Type 2 diabetes can be significantly improved or even put into remission through lifestyle changes alone — particularly weight loss. Even a 5 to 10% reduction in body weight can dramatically improve insulin sensitivity.

  • Diet — reduce refined carbohydrates and sugary drinks; increase vegetables, legumes, whole grains, and lean protein
  • Exercise — 150 minutes of moderate activity per week; resistance training is particularly effective for improving insulin sensitivity
  • Weight loss — the single most effective intervention for Type 2 diabetes

Medications for Type 2

When lifestyle changes are not sufficient, medications are added:

  • Metformin — the first-line medication; reduces glucose production in the liver and improves insulin sensitivity. Inexpensive, well-tolerated, and used for decades
  • Sulfonylureas (glibenclamide, glipizide) — stimulate the pancreas to produce more insulin
  • SGLT2 inhibitors — cause the kidneys to excrete excess glucose in urine; also protect the heart and kidneys
  • GLP-1 receptor agonists — slow digestion, reduce appetite, and lower blood sugar; also promote weight loss
  • Insulin — may eventually be needed as Type 2 progresses and the pancreas produces less insulin

Diabetes is a lifelong condition but it is manageable. People with well-controlled diabetes live full, healthy lives. The key is early detection, consistent management, and never stopping treatment because you feel fine — blood sugar can be dangerously high with no symptoms at all. Check your levels regularly. Know your numbers.