Types of diabetes: what diabetes is, and how type 1, type 2 and gestational diabetes differ

Diabetes, also called diabetes mellitus, is a long-term condition in which there is too much glucose, a type of sugar, in your blood. Many Filipinos simply call it "sugar", as in "may sugar" or "mataas ang sugar".

Your body uses glucose from food for energy. A hormone called insulin, made by the pancreas (an organ behind the stomach), moves glucose from the blood into your cells. In diabetes, the body makes too little insulin, cannot use it well, or both, so glucose stays in the blood.

Over the years, high blood sugar damages blood vessels and nerves. It can lead to blindness, kidney failure, heart attack, stroke and foot wounds that may end in amputation. Good control prevents or delays these problems.

In the Philippines, the 2023 National Nutrition Survey found a fasting blood sugar in the diabetes range in about 7 or 8 of every 100 adults aged 20 to 59, and about 17 of every 100 aged 60 and over.

• Type 1 diabetes: the body makes little or no insulin. It often starts in children and young adults and needs insulin every day.
• Type 2 diabetes: the body makes insulin, but it does not work well or there is not enough. At least 9 in every 10 people with diabetes have type 2.
• Gestational diabetes: high blood sugar that starts in pregnancy and usually goes away after birth.
• Prediabetes: blood sugar higher than normal but not yet in the diabetes range.
• Rarer types: monogenic diabetes, caused by a change in a single gene, and diabetes after damage to the pancreas, for example from pancreatitis or surgery.

The type matters because the treatment differs. A doctor works it out from your age, weight, symptoms and blood tests, sometimes with extra tests.

Type 1 is an autoimmune condition: the body's defense system (the immune system) attacks, by mistake, the cells in the pancreas that make insulin. Nobody knows exactly why; genes and something in the environment may both play a part.

It was once called "juvenile" diabetes because it often starts in children and young adults, but it can begin at any age. A parent, brother or sister with type 1, or another autoimmune condition, makes it more likely.

In children, symptoms usually come quickly, over days or weeks; in adults they may come more slowly. Without insulin, the body breaks down fat for energy and makes acids called ketones. When they build up, they cause diabetic ketoacidosis (DKA), a life-threatening emergency that is sometimes the first sign of type 1, mostly in children.

Type 1 cannot be prevented and has no cure yet. It is managed with daily insulin, blood sugar checks and attention to food and activity.

Type 2 usually starts with insulin resistance: the cells in your muscles, fat and liver stop responding well to insulin. The pancreas makes extra insulin to keep up, until it no longer can, and blood sugar rises.

It often develops slowly, over years, with mild symptoms or none, so some people only find out after it has harmed their eyes, kidneys or heart. It is most common in older adults, but young people can get it too.

Philippine screening guidelines, made with the Department of Health, count these as risk factors:

• extra weight (for Filipinos, a body mass index or BMI of 23 or more) or a large waist
• a parent, brother or sister with type 2
• little physical activity
• prediabetes, high blood pressure, heart disease or a past stroke
• gestational diabetes before, or a baby of about 8 pounds or more at birth
• polycystic ovary syndrome (PCOS), or dark, velvety skin on the neck or armpits (acanthosis nigricans)

Smoking and age also raise the risk, so the guidelines advise a fasting blood sugar test from age 40, or earlier with any risk factor.

Gestational diabetes is high blood sugar that starts during pregnancy, most often in the second or third trimester, when the body cannot make the extra insulin pregnancy needs.

It usually has no symptoms, so it is found with a blood test at prenatal check-ups, most often the oral glucose tolerance test (OGTT) between weeks 24 and 28. The chance is higher if you are overweight, had it in an earlier pregnancy, once had a baby of 4.5 kilos (10 pounds) or more, or have a parent, brother or sister with diabetes. Sometimes the diabetes found in pregnancy is type 2 that was already there.

Found early and controlled, it usually ends with a healthy baby. Uncontrolled, it can make the baby grow very large, so a cesarean section is more likely, and it raises the chance of early birth, pre-eclampsia (high blood pressure in pregnancy) and low blood sugar or jaundice in the newborn.

It usually goes away after birth, but it raises the chance of type 2 later and of gestational diabetes next time. Have a blood sugar test 6 to 13 weeks after giving birth, then once a year. See our prenatal check-up guide.

Prediabetes means your blood sugar is above normal but not yet in the diabetes range. It usually has no symptoms. In the 2023 National Nutrition Survey, about 2 in 10 Filipino adults aged 20 to 59, and more than 1 in 3 aged 60 and over, had a fasting blood sugar in this range. It carries a high chance of type 2 within 5 to 10 years, but that is not certain: losing extra weight, eating better and moving more can bring blood sugar back to normal. With prediabetes, get a diabetes test every year.

High blood sugar causes similar signs in every type: strong thirst, peeing more (often at night), tiredness, weight loss without trying, blurred vision, and cuts or infections that heal slowly. What differs is the speed:

• Type 1: often fast and strong, over days or weeks, especially in children. Vomiting, belly pain, fruity breath or fast, deep breathing can mean DKA.
• Type 2: slow, over years, or no symptoms at all.
• Gestational diabetes and prediabetes: usually no symptoms.

Symptoms cannot show whether you have diabetes, or which type; only blood tests can. Our diabetes symptoms guide covers the early signs and the tests (FBS, HbA1c and OGTT).

• Type 1: the immune system destroys the insulin-making cells. It is not caused by sweets or by anything the person or the parents did.
• Type 2: genes and family history, together with extra weight, too little activity, smoking and age.
• Gestational diabetes: the hormone changes of pregnancy, together with genes and lifestyle.
• Other causes: a single gene change, damage to the pancreas, and some medicines taken for a long time, such as steroid medicines (glucocorticoids). Never stop a prescribed medicine on your own; ask your doctor first.

Treatment keeps blood sugar in a healthy range to prevent complications. Your doctor sets your targets and chooses your medicines, which all need a prescription; this guide does not give doses.

• Type 1: insulin every day, by injection or pump, to stay alive, plus blood sugar checks. Never stop insulin, even on days you eat little.
• Type 2: healthy eating, activity and losing extra weight first. Many people also need medicines such as metformin, gliclazide or dapagliflozin, and some later need insulin. Needing more medicine over time is common, not a personal failure. For some, weight loss can bring blood sugar back to normal (remission), which still needs check-ups.
• Gestational diabetes: diet changes, gentle activity such as walking and home sugar checks, with tablets or insulin if needed.
• Prediabetes: lifestyle change, sometimes with metformin.

Insulin and some tablets, such as gliclazide, can make blood sugar go too low (hypoglycemia). Early signs are hunger, sweating, shaking, a pounding heartbeat and feeling nervous. If the person is awake and can swallow, give something sugary right away, such as fruit juice or a regular (not diet) soft drink, and go to the emergency room if they do not improve. Never put food or drink in the mouth of someone who is unconscious: lay them on their side and call 911.

Many people with diabetes also need care for high blood pressure and cholesterol. Questions? Try our AI diabetes coach or ask a nurse.

Type 1 cannot be prevented. Type 2 often can be prevented or delayed, and the same habits may lower the risk of gestational diabetes. WHO advises keeping a healthy weight, being active for at least 150 minutes a week, eating a healthy diet low in sugar and saturated fat, and not smoking.

In daily life that can mean water instead of soft drinks and sweet coffee mixes, more vegetables such as malunggay, kangkong or pechay, and a brisk walk on most days. See our guide on how to prevent diabetes, and add a blood sugar test to your annual check-up.

PhilHealth YAKAP is for every Filipino. You register with one YAKAP clinic, such as your rural health unit (RHU), city health center or an accredited private clinic.

• Tests: FBS, OGTT and HbA1c are on PhilHealth's list of covered primary care tests, with lipid profile, creatinine (a kidney test), urinalysis and ECG, when your YAKAP doctor orders them. As of July 2025, public YAKAP clinics are free and private ones may charge up to ₱900 per patient for the whole year.
• Medicines: as of January 2026, metformin and gliclazide are among the 21 medicines given at YAKAP clinics. With a prescription from your YAKAP doctor, PhilHealth GAMOT pharmacies also give listed medicines such as dapagliflozin, up to ₱20,000 worth a year per person.
• Insulin is not on the GAMOT list of 75 medicines that PhilHealth issued in 2025. Ask your doctor or health center where to get it.

See our PhilHealth YAKAP guide to register, and what PhilHealth covers for hospital care such as DKA. Find an RHU or health center or book a call.