Yes, diabetes is a metabolic disease. It is formally classified as a metabolic disorder of multiple causes, characterized by chronic high blood sugar along with disruptions in how the body processes carbohydrates, fats, and proteins. These disruptions all trace back to a single hormone: insulin, which either isn’t produced in sufficient quantities or doesn’t work properly in the body’s cells.
As of 2024, an estimated 589 million adults worldwide are living with diabetes, roughly 11% of the global adult population. That number is projected to reach 853 million by 2050.
What Makes a Disease “Metabolic”
Metabolism refers to every chemical process your body uses to convert food into energy, build and repair tissue, and dispose of waste. A metabolic disease occurs when one or more of these processes breaks down, causing the body to have too much or too little of a substance it needs to function. In diabetes, the core breakdown involves glucose, the sugar your cells use as fuel. Glucose builds up in the bloodstream instead of entering cells, and this single malfunction sets off a cascade of problems across multiple metabolic pathways.
What makes diabetes especially significant as a metabolic disease is that it rarely stays confined to blood sugar. It almost always travels with other metabolic abnormalities: high blood pressure, abnormal cholesterol levels, and changes in how the blood clots. When these cluster together, the combination is called metabolic syndrome, and it dramatically increases the risk of heart disease and stroke.
How Metabolism Fails in Type 1 vs. Type 2
Both major types of diabetes are metabolic diseases, but the underlying failure is different.
In type 1 diabetes, the immune system attacks and destroys the insulin-producing cells in the pancreas (called beta cells). With fewer beta cells, insulin production drops or stops entirely. Without insulin, glucose can’t enter cells and accumulates in the blood. This form accounts for about 5 to 10% of all diabetes cases and requires insulin replacement from the point of diagnosis.
In type 2 diabetes, the pancreas still makes insulin, but the body’s cells stop responding to it properly. Think of insulin as a key and the cell as a locked door. In type 2, the locks are damaged, so the key no longer fits. Glucose can’t get through, and blood sugar rises. The pancreas tries to compensate by producing extra insulin, but eventually it can’t keep up. This combination of insulin resistance and declining insulin production is what drives type 2 diabetes, which represents about 90 to 95% of cases.
The Ripple Effect on Fat and Cholesterol
Diabetes doesn’t just disrupt sugar metabolism. It fundamentally alters how the body handles fats, creating a pattern known as diabetic dyslipidemia. This pattern includes elevated triglycerides, low levels of HDL (the “good” cholesterol), and a shift in LDL particles toward a smaller, denser form that is more likely to contribute to artery-clogging plaque.
Several mechanisms drive these changes. The liver overproduces certain fat-carrying proteins in the presence of insulin resistance. An enzyme that normally clears triglycerides from the blood works less efficiently. After meals, dietary fat lingers in the bloodstream longer than it should, a phenomenon that has been directly correlated with accelerated atherosclerosis in clinical studies. Meanwhile, the body’s cholesterol-shuttling system essentially swaps protective cholesterol out of HDL particles and replaces it with triglycerides, shrinking the HDL and reducing its ability to protect blood vessels.
This is why cardiovascular disease is the leading cause of death among people with type 2 diabetes. The metabolic disruption extends far beyond blood sugar.
Metabolic Syndrome and Diabetes Risk
Metabolic syndrome is diagnosed when a person has at least three of the following five conditions:
- Large waist circumference: 40 inches or more in men, 35 inches or more in women
- Elevated triglycerides: 150 mg/dL or higher
- Low HDL cholesterol: below 40 mg/dL in men, below 50 mg/dL in women
- High blood pressure: 130/85 mmHg or higher
- Elevated fasting blood sugar: 100 mg/dL or higher
Diabetes and metabolic syndrome are deeply intertwined. People with metabolic syndrome who don’t yet have type 2 diabetes face roughly five times the risk of developing it compared to people without the syndrome. The syndrome also doubles the risk of cardiovascular events like heart attacks and strokes. Elevated fasting glucose is one of the five diagnostic criteria, placing blood sugar disturbance at the center of the cluster.
How Diabetes Is Diagnosed
Because diabetes is defined by a metabolic marker (blood glucose that stays too high), diagnosis relies on measuring that marker in different ways. The American Diabetes Association recognizes three primary tests:
- A1C test: Measures average blood sugar over the past two to three months. Normal is below 5.7%, prediabetes falls between 5.7% and 6.4%, and diabetes is diagnosed at 6.5% or higher.
- Fasting plasma glucose: Measures blood sugar after an overnight fast. Normal is below 100 mg/dL, prediabetes is 100 to 125 mg/dL, and diabetes starts at 126 mg/dL.
- Oral glucose tolerance test: Measures blood sugar two hours after drinking a sugary solution. Normal is below 140 mg/dL, prediabetes is 140 to 199 mg/dL, and diabetes is 200 mg/dL or above.
Each of these tests captures a different window into how well your metabolism is handling glucose. Your doctor may use one or more depending on the clinical situation.
Can the Metabolic Damage Be Reversed?
For type 1 diabetes, the destruction of insulin-producing cells is permanent, so the metabolic failure cannot currently be reversed.
Type 2 diabetes is a different story. Research has shown that substantial weight loss can reverse the underlying metabolic processes. In one well-studied intervention, participants who lost significant weight saw their liver fat content drop from an average of 16% to 3%, and both pancreas fat and blood triglycerides decreased as well. Those whose insulin-producing cells still had enough capacity to recover achieved normal blood sugar levels, and that improvement held at 12 months.
The likelihood of remission depends on two key factors: how long someone has had diabetes, and whether the beta cells in the pancreas retain the ability to bounce back. People who achieved remission had an average diabetes duration of about 2.7 years, compared to 3.8 years for those who did not. The longer the metabolic disruption persists, the harder it becomes for the pancreas to recover its first-phase insulin response, the quick burst of insulin your body releases the moment blood sugar starts to rise.
This reinforces something important about diabetes as a metabolic disease: the metabolic dysfunction is not just about sugar. It involves fat stored in the liver and pancreas, altered lipid processing, and the gradual exhaustion of insulin-producing cells. Addressing the full metabolic picture, not just blood glucose, is what gives people the best chance of meaningful improvement.