Understanding Diabetes: What It Is, Types, Symptoms & Treatments

Understanding Diabetes: What It Is, Types, Symptoms & Treatments
Medically Reviewed By:
Mark Arredondo, M.D.

Glucose, also commonly called blood sugar, is the main source of energy for the body. Diabetes is a disease where your blood sugar is too high. 

Your pancreas makes the hormone insulin, which helps glucose enter your cells from your bloodstream so it may be used for energy. When you have diabetes, your pancreas doesn’t make enough insulin or your body can’t use the insulin properly. This leaves too much glucose floating around the bloodstream instead of entering cells. 

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), more than 133 million Americans have diabetes or a blood sugar level that is higher than normal and are at risk of developing diabetes. 

Diabetes puts you at risk for a number of health problems, as having high blood sugar may damage your heart, kidneys, eyes and nerves. Diabetes has also been linked to certain cancers

Diabetes types 

There are different types of diabetes. Of them, the most common are type 1, type 2 and gestational diabetes, according to NIDDK

Type 1 diabetes 

With this type of diabetes, your body makes little or no insulin. The cells in the pancreas meant to make insulin have been destroyed by the immune system. Children and young adults are most likely to be diagnosed with type 1 diabetes. However, you may be diagnosed with type 1 at any age. If you have type 1 diabetes, you must take insulin every day to live. 

Type 2 diabetes

Type 2 diabetes is the most common type. People with type 2 diabetes don’t use insulin properly, and sometimes the pancreas is also not making the amount of insulin needed to keep their blood sugar levels within a normal range. People who are overweight or obese and who have a family history of diabetes are at higher risk for developing type 2. You may develop type 2 at any age, even as a child. 

Gestational diabetes

This type of diabetes develops when pregnant. Often, gestational diabetes will go away after the baby is delivered. However, those who have gestational diabetes are at risk for developing type 2 diabetes later on in their lives. According to the American Diabetes Association (ADA), nearly 10% of pregnancies are affected by gestational diabetes each year.

Gestational diabetes is different from other types of diabetes in that it’s not caused by insufficient insulin production. Rather, other hormones produced during pregnancy make the insulin less effective. This condition is known as insulin resistance.

The U.S. Preventive Services Task Force recommends that everyone who is pregnant be tested for gestational diabetes at or after 24 weeks pregnant.


When your blood sugar is higher than normal but it’s not high enough to be called diabetes, you have what’s known as prediabetes. Prediabetes puts you at higher risk of developing diabetes. You are also at higher risk of developing heart disease than those who have normal blood sugar levels. 

Most people who develop type 2 diabetes start with prediabetes. You may be able to prevent or delay developing full-blown diabetes with early treatment and moderate lifestyle changes. 

Diabetes symptoms

The symptoms of diabetes may vary depending on the type. Here are the common symptoms for each type:

Type 1

With type 1 diabetes, the onset may be sudden. 

Signs of type 1 diabetes in children may include:

  • Frequent urination

  • Insatiable thirst

  • Weight loss

  • Tired more than usual

  • Bedwetting after being fully trained and dry at night 

Signs of type 1 diabetes in adults may include:

  • Frequent urination

  • Constant thirst

  • Hunger despite eating

  • Extreme fatigue

  • Vision that is blurry at times

  • Cuts and bruises that take long to heal

  • Weight loss despite eating more

Type 2

Signs of type 2 diabetes may include:

  • Frequent urination

  • Constant thirst

  • Hunger despite eating

  • Extreme fatigue

  • Vision that is blurry at times

  • Cuts and bruises that take long to heal

  • Tingling, pain or numbness in your hands and feet

Gestational diabetes 

It’s possible to have gestational diabetes and no symptoms. That’s why it’s important to be tested during pregnancy. 

If they do occur, symptoms of gestational diabetes may include:

  • Urinating more than usual

  • Feeling hunger and thirst more than usual 


You’re not likely to have any clear symptoms of prediabetes. It’s important to talk with your healthcare provider about being screened if you have any risk factors for diabetes.

Diabetes treatment 

Several diabetes medications and lifestyle changes are used to treat diabetes and maintain good glucose control. 

Here’s a look at treatments by diabetes type:

Type 1

Treatment for type 1 diabetes may include:

  • Taking insulin through a needle and syringe, insulin pen, or insulin pump with or without an automated insulin delivery system

  • Following a diet where you count and eat specific amounts of carbohydrates, fats and proteins and eat healthy 

  • Monitoring your blood glucose regularly

  • Maintaining a healthy weight

  • Exercising regularly

There are many types of insulin for people with type 1 diabetes, and they differ in how much time they each take to start working and how long they last. Some premixed insulins are a mixture of different insulin types. Patients should work closely with their healthcare provider to decide on the appropriate insulin therapy.

Type 2 

Much like type 1, treatments for type 2 diabetes may include:

  • Eating healthy 

  • Exercising regularly

  • Losing weight if living with overweight or obesity

  • Taking medication or insulin therapy with pills or injections

  • Monitoring your blood sugar 

Metformin. Metformin is typically the first medicine you’re given, NIDDK says. It works by lowering the amount of sugar produced in the liver and improving your body’s sensitivity to insulin. As a result, you use insulin more efficiently.

According to the U.S. Food and Drug Administration, other medications for type 2 diabetes may include:

  • Sulfonylureas. This medication helps your body secrete more insulin. 

  • Meglitinides. This medication is designed to stimulate the pancreas to secrete more insulin at mealtime. 

  • Alpha-glucosidase inhibitors. These medications slow the digestion of sugar.

  • Thiazolidinediones. This medication makes cells more sensitive to insulin. 

  • DPP-4 inhibitors. This medication is designed to help the body release more insulin. 

  • GLP-1 receptor agonists. This medication is injected and designed to slow digestion and help lower blood sugar levels. Examples include semaglutide (Ozempic, Wegovy). 

  • SGLT2 inhibitors. This medication works by affecting the blood-filtering functions in the kidneys by blocking the return of glucose to the bloodstream. As a result, glucose is removed in the urine.

  • Biguanides. These medications limit sugar produced in the liver.

Combination medicines, typically with metformin plus another drug, may also be recommended.

Each of these medications has possible side effects, which may include:

Some other tools to treat and manage type 2 diabetes may include:

Insulin therapy

In addition to medication, some people with type 2 diabetes will need insulin therapy. For years, insulin therapy was only used when absolutely necessary, but today it may be started earlier in people who can’t seem to get their blood sugar under good control with other medications and lifestyle changes. 

There are different types of insulin—short-acting used at mealtime and long-acting meant to work overnight and throughout the day. Most insulin is injected. You and your healthcare provider will determine which type or types you need and when you should take it. 

Weight-loss surgery 

Weight-loss surgery may be an option for adults living with type 2 diabetes who have a body mass index (BMI) of 35 or higher or who have severe diabetes as well as other medical conditions. The surgery helps patients lose weight and manage type 2 diabetes and other medical conditions that may be related to obesity. The surgery changes the shape and function of your digestive system, making it difficult to overeat. Some surgical procedures also limit the amount of nutrients your body may absorb.

Gestational diabetes

Your age, overall health, medical history and extent of your disease all help determine how your gestational diabetes is treated. Your preferences and opinions will also be a factor. The goal is to keep your blood sugar levels within a normal range. 

Treatment options may include:

  • Following a special diet

  • Exercising

  • Monitoring blood sugar daily

  • Getting insulin injections 

During labor, your blood sugar will be monitored closely. You may be given insulin while in labor to prevent your baby’s blood sugar from dropping after they’re born. 

Is there a best diet for diabetes? 

When you have diabetes, it’s important that you eat sensibly, choosing healthy foods in moderate amounts. A dietitian may help you plan meals that will help you to control your blood sugar and lose or gain weight if that’s also needed. In addition, you may need to eat on a schedule to keep your blood sugar on an even keel. 

Experts at the Joslin Diabetes Center recommend that each meal is balanced, pairing protein with carbs and healthy fats in one meal or snack for more stable glucose levels.

The NIDDK recommends these types of foods if you have diabetes:

Healthy carbs. The sugars and starches you eat break down during digestion into blood sugar. Healthy carbs include:

  • Fruits

  • Vegetables

  • Whole grains

  • Legumes (beans and peas, for example)

Fiber-forward foods. Some of these are also healthy carbs.

  • Fruits

  • Vegetables

  • Legumes

  • Whole grains 

  • Nuts

Heart-healthy proteins. Protein provides key amino acids and helps you maintain muscle. 

  • Lean meat, such as chicken or turkey without the skin

  • Fish high in omega-3 fatty acids, such as salmon, tuna and sardines

  • Eggs

  • Dried beans and certain peas, such as chickpeas and split peas

  • Meat substitutes, such as tofu

Good fats. Although fats are high in calories, good fats contain monounsaturated and polyunsaturated fats that may help lower cholesterol. Examples include:

  • Avocados

  • Nuts

  • Canola oil

  • Olive oil

  • Peanut oil 

Dairy. Choose nonfat or low-fat dairy options among yogurt, cheese and milk products. 

Foods to limit or avoid may include:

  • Foods that are high in saturated fat, such as butter, red meat, hot dogs, sausage, bacon, coconut oil and palm kernel oil. 

  • Foods high in cholesterol, such as liver and other organ meats and high-fat dairy products.

  • Foods high in sodium. This is especially important if you have high blood pressure

  • Foods that are highly processed, as they may contain trans fats and excess salt and sugar. Avoid table sugar, candy, soda and jelly, as these simple sugars may up your blood sugar. 

Living with diabetes

Diabetes is a chronic condition. It’s something you must live with every day. Some things you may do to help manage it include:

Monitor your blood sugar. Test your blood sugar and keep track of the results. Discuss with your healthcare team if your numbers fluctuate too much. 

Follow your treatment plan. If you’re on medications, take them as they’re prescribed, even on days that you feel fine. 

Watch your weight. The more weight you carry, the harder it is to manage your diabetes. Being overweight also increases your risk of high blood cholesterol and high blood pressure, both of which are risk factors for cardiovascular disease. 

Eat healthy. Making healthful food choices will not only help you achieve a healthy weight, but also better manage your diabetes. 

Quit smoking. Smoking may make diabetes worse, and it may make it more likely to experience nerve damage and kidney disease. Talk to your healthcare provider if you need help quitting. 

Reduce stress. Stress may make it difficult to manage your diabetes properly. It may make it hard to sleep and cause other aches and pains, including stomach upset. 

Stay active. Exercise is important when you have diabetes. Physical activity may help you control your blood sugar levels and lower your risk for heart disease and nerve damage. You may need to check your blood sugar levels before and after exercising. Also, be sure to stay hydrated during exercise and wear shoes and socks that fit well and that are comfortable to avoid sores, blisters and irritation. 

Learn more. The more you know about diabetes and your care, the better. A certified diabetes educator may help. Talk to your healthcare providers when issues arise, and stay on top of your treatment plan.


National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): What is Diabetes?

American Diabetes Association (ADA): Understanding Type 1 Diabetes

ADA: Gestational Diabetes

NIDDK: Symptoms and Causes of Gestational Diabetes.

U.S. National Library of Medicine: Metformin

U.S. Food and Drug Administration: Diabetes Medicines

Centers for Disease Control and Prevention (CDC): Prediabetes – Your Chance to Prevent Type 2 Diabetes

NIDDK: Insulin, Medicines, & Other Diabetes Treatments

Joslin Diabetes Center: Carbs, Protein and Fats – Their Effect on Glucose Levels.

NIDDK: Diabetes Diet, Eating, & Physical Activity

American Heart Association: Living Healthy with Diabetes

CDC: Get Active!

CDC: Living Well with Diabetes

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