What Is Diabetes? Types, Symptoms, Causes, and Support From a Registered Dietitian and Diabetes Educator

What Is Diabetes?

Diabetes is a chronic condition that affects how your body processes dietary sugar, or glucose. Normally, your body breaks carbohydrates down into glucose, which enters your bloodstream, and insulin helps move that glucose into your cells to be used for energy. In diabetes, your body either does not make enough insulin, does not use insulin well (“insulin resistance”), or both. When that happens, too much glucose stays in the blood, which can lead to health problems over time.

As a registered dietitian and diabetes educator, I help translate the science of diabetes into practical, realistic steps you can actually use in everyday life. That combination matters: a diabetes care and education specialist provides individualized education and support, and dietitian-delivered medical nutrition therapy has been associated with improvements in A1C, fasting blood sugar, weight, blood pressure, and other cardiometabolic outcomes.

What are the different types of diabetes?

Type 1 diabetes

Type 1 diabetes happens when the immune system attacks and destroys the insulin-producing cells in the pancreas. People with type 1 diabetes make little or no insulin and need insulin every day to stay alive. Type 1 is an autoimmune disease and is not caused by dietary or lifestyle habits.

Type 2 diabetes

Type 2 diabetes is the most common form of diabetes. In type 2, the body becomes resistant to insulin, and over time the pancreas may not be able to keep up with the body’s increased insulin needs. According to CDC, about 90% to 95% of people with diabetes have type 2 diabetes.

Gestational diabetes

Gestational diabetes develops during pregnancy in someone who did not already have diabetes. It often appears around the 24th week of pregnancy and may not cause obvious symptoms, which is why screening is so important. Gestational diabetes also matters beyond pregnancy because it increases future risk for developing type 2 diabetes.

What are the symptoms of diabetes?

Common symptoms of diabetes can include increased urination, feeling very thirsty, feeling very hungry, blurred vision, fatigue, sores that do not heal, and frequent infections. Type 2 diabetes can develop slowly and sometimes has no noticeable symptoms at all, while type 1 diabetes may come on more quickly and can become severe.

In type 1 diabetes, warning signs can also include unexplained weight loss, nausea, vomiting, abdominal pain, fruity-smelling breath, trouble breathing, or diabetic ketoacidosis. Those symptoms need urgent medical attention.

How is diabetes diagnosed?

Diabetes is diagnosed with blood testing. Common criteria include an A1C of 6.5% or higher, a fasting blood glucose of 126 mg/dL or higher, a 2-hour oral glucose tolerance test result of 200 mg/dL or higher, or a random blood glucose of 200 mg/dL or higher in the setting of severe symptoms.

Prediabetes means blood sugar is higher than normal, but not yet in the diabetes range. On the ADA criteria page, prediabetes is defined as an A1C of 5.7% to 6.4%, fasting glucose of 100 to 125 mg/dL, or a 2-hour OGTT of 140 to 199 mg/dL. Prediabetes increases the risk of developing type 2 diabetes and cardiovascular disease.

Who is at risk for type 2 diabetes?

Risk factors for type 2 diabetes include prediabetes, overweight or obesity, age 45 or older, family history of type 2 diabetes, physical inactivity, a history of gestational diabetes, and certain health conditions such as non-alcoholic fatty liver disease. Risk is also higher in some racial and ethnic groups, including African American, Hispanic or Latino, American Indian, Alaska Native, some Pacific Islander, and some Asian American populations.

One important point: not all diabetes is preventable. Type 1 diabetes is autoimmune and currently cannot be prevented in the way type 2 diabetes often can be delayed or prevented. Type 2 diabetes risk, on the other hand, can often be reduced through lifestyle changes.

How is diabetes managed?

Diabetes management is not just about “avoiding sugar.” It usually includes a combination of balanced eating, regular physical activity, blood sugar monitoring when appropriate, medications or insulin when needed, stress management, sleep, and regular follow-up care. The goal is not perfection. The goal is consistent habits that help keep blood sugar in range and reduce the risk of complications.

Nutrition is one of the most powerful tools in diabetes care, but there is no single perfect “diabetes diet.” The ADA emphasizes practical, evidence-based nutrition guidance that can be tailored to the person, and NIDDK notes that working with a registered dietitian can help create a meal plan that fits your health needs, lifestyle, and preferences.

Why work with a Registered Dietitian and Diabetes Educator?

As a registered dietitian and diabetes educator, I bring together two parts of care that people with diabetes usually need most: clear nutrition guidance and practical education on medication and insulin options. That means helping you understand what diabetes is, how food affects blood sugar, how to build balanced meals, how to read trends in your glucose, what your medication options are, and how to fit all of this into real life.

Diabetes is managed by turning information into daily habits. Evidence shows that diabetes self-management education and support improves outcomes, and systematic reviews have found benefits from both diabetes education interventions and dietitian-led medical nutrition therapy.

Dietitian Takeaway

Diabetes is common, serious, and often misunderstood. The good news is that with the right education, support, and treatment plan, it can be managed very effectively. Whether you are newly diagnosed, at risk for diabetes, or trying to make sense of prediabetes, the first step is understanding what is happening in your body and what tools are available to help.

Reach out to us today for more information and to schedule your appointment!

Resources and References

American Diabetes Association. Diabetes Diagnosis & Tests. Clear overview of how diabetes and prediabetes are diagnosed, including A1C, fasting glucose, OGTT, and random glucose criteria. https://diabetes.org/about-diabetes/diagnosis

American Diabetes Association. Standards of Care in Diabetes—2026. Current ADA clinical guidance for diabetes screening, diagnosis, prevention, and management. https://professional.diabetes.org/standards-of-care

Centers for Disease Control and Prevention. Diabetes Basics. Plain-language overview of what diabetes is and the three main types. https://www.cdc.gov/diabetes/about/index.html https://www.cdc.gov/diabetes/about/about-type-2-diabetes.html?utm_source=chatgpt.com

National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & Causes of Diabetes. Helpful summary of symptoms, causes, and when to talk with a healthcare professional. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes?utm_source=chatgpt.com

Centers for Disease Control and Prevention. About Diabetes Self-Management Education and Support (DSMES). Explains the role of diabetes education in building day-to-day self-management skills. https://www.cdc.gov/diabetes/about/about-type-2-diabetes.html https://www.cdc.gov/diabetes/about/gestational-diabetes.html

Association of Diabetes Care & Education Specialists. Role of the Diabetes Care and Education Specialist. Useful background on what a diabetes educator/DCES does. https://www.adces.org/dces-career

Razaz JM, Rahmani J, Varkaneh HK, et al. The health effects of medical nutrition therapy by dietitians in patients with diabetes: A systematic review and meta-analysis. Primary Care Diabetes. 2019. This review found significant improvements in fasting blood sugar, A1C, weight, BMI, cholesterol, and systolic blood pressure with medical nutrition therapy. https://pubmed.ncbi.nlm.nih.gov/31186171/

Chowdhury HA, et al. The effectiveness of diabetes self-management education intervention on glycaemic control and cardiometabolic risk in adults with type 2 diabetes in low- and middle-income countries: A systematic review and meta-analysis. PLOS One. 2024. This review found that DSME improved HbA1c and other self-management and psychosocial outcomes https://pubmed.ncbi.nlm.nih.gov/38306363/