Manage Blood Sugar

Most of the food you eat is broken down into sugar (also called glucose) and released into your bloodstream for use as your body’s main source of energy.

Diabetes is a condition in which blood sugar levels are too high. If you have type 1 or type 2 diabetes, it is very important to keep your blood sugar numbers in your target range. You may need to check your blood sugar levels several times each day.

What happens when sugar enters the body?

  • Your pancreas releases insulin when your blood sugar goes up after eating.
  • Insulin acts like a key to let the blood sugar into your body’s cells for use as energy.
  • When blood sugar and insulin are high in the blood, the liver absorbs blood sugar and stores it as glycogen. The liver can turn it back into blood sugar later when it’s needed for energy.

How do I measure my blood sugar levels?

  • If you have type 1 or type 2 diabetes, there are two ways to measure blood sugar:
    • Blood sugar checks that you do yourself. These numbers tell you what your blood sugar level is at the time you test. Blood sugar monitoring is very important for people with diabetes.
    • The A1C test is done in a lab or at your doctor’s office. The A1C test is a measure of the average blood sugar level over the past 3 months. It also helps your health care team decide the type and amount of diabetes medicine you may need.

Managing your diabetes can help keep you from having other serious health problems, such as heart disease, stroke, kidney disease, nerve damage, poor oral health, and vision loss.

Blood sugar level test. Diabetes vector medical concept illustration of hands with glucose meter machine isolated on white background.

What are blood sugar level targets?

A blood sugar target is the individual blood sugar range you try to reach as much as possible. Your health care team may also use the term goal. People who have diabetes have blood sugar targets for different times of the day. Your health care team will recommend a blood sugar target for you. These are typical targets:

  • Before your meal: 80 to 130 mg/dl.
  • Two hours after the start of the meal: Less than 180 mg/dl.

Times to check your blood sugar include the following:

  • When you first wake up (fasting).
  • Before a meal level.
  • Two hours after a meal.
  • At bedtime.

The number of times you check your blood sugar will depend on the type of diabetes you have and if you take diabetes medicine. People who take insulin may need to check more often than people who don’t.

What causes blood sugar to be high or low?

Checking your blood sugar levels regularly helps track what makes your numbers go up and down. For example, being sick, stress, or eating certain foods may cause your numbers to go up. Or when you take your medicine, get more active, or eat less than usual, your numbers may go down.

  • High blood sugar, also known as hyperglycemia, means your blood sugar level is higher than your target level. If this continues over time, it can lead to long-term, serious health problems. Some symptoms of high blood sugar include the following:
    • Feeling very tired.
    • Feeing thirsty.
    • Having blurry vision.
    • Needing to urinate (pee) more often.

If you are sick and your blood sugar stays over 240 mg/dl after 2 checks, call your doctor. If you have type 1 diabetes, be sure to check your urine for ketones. If you have the flu, review flu and sick days for special instructions.

What are ketones, ketosis, and ketoacidosis?

These terms sound similar, but they affect people who have diabetes differently.

  • Ketones: When there isn’t enough sugar in the body for activities, the liver releases enough sugar to be used for parts of the body like the brain, red blood cells, and parts of the kidney. For the rest of the body, the liver makes an acid called ketones that breaks down body fat for energy.
  • Ketosis: If blood sugar is in the normal range, ketones are generally not harmful. Ketosis occurs when the level of ketones in your blood or urine is high, but not high enough to cause ketoacidosis. You can be in ketosis if you’re on a low-carbohydrate diet or fasting.
  • Ketoacidosis: If you have type 1 diabetes, you may build up too many ketones in your blood and develop diabetic ketoacidosis (DKA). DKA is a very serious condition that could lead to coma or death. It’s rare in people with type 2 diabetes, but could be a side effect of some medicines used for type 2 diabetes. If your blood sugar stays over 240 mg/dL after 2 checks, you should test your urine for ketones.

Some people choose to be in ketosis when they go on a low-carb diet to help with weight loss (such as the Ketogenic Diet or Atkins).

Talk to your doctor and health care team before beginning any diet plan. If you have type 1 diabetes, it is very important to talk to your doctor or health care team before going on a low-carb diet.

Diabetic Glucometer Blood sugar level testing kit

Low blood sugar, also known as hypoglycemia, means your blood sugar level dropped below 70 mg/dl and is more common in people with type 1 diabetes. Low blood sugar is dangerous and should be treated as soon as possible. If you take insulin or certain pills for diabetes, you have a greater risk of having low blood sugar whether you have type 1 or type 2 diabetes.

Carry supplies for treating low blood sugar with you. If you feel shaky, sweaty, or very hungry, check your blood sugar. Even if you feel none of these symptoms, but think you may have low blood sugar, check it. If your blood sugar is lower than 70 mg/dl, do one of the following things right away:

  • Take four glucose tablets.
  • Drink four ounces of fruit juice.
  • Drink four ounces of regular soda, not diet soda.
  • Eat four pieces of hard candy.

After one of these treatments, wait for 15 minutes, then check your blood sugar again. Repeat until your blood sugar is 70 mg/dl or above, and eat a snack if your next meal is one hour or more away. If you have low blood sugar often, check your blood sugar before driving, and if it is low, treat it right away.

How do carbs affect blood sugar levels?

Carbohydrates, or carbs, have a direct effect on your blood sugar levels. Along with proteins and fats, carbs are one of three main nutrients found in foods and drinks. If you have diabetes, planning what you eat is very important. Counting carbs—adding up all the carbs in everything you eat and drink—is a tool you can use to help you manage blood sugar levels.

Visit Diabetes and Carbs for more information about carbs and blood sugar.

What else can I do to help manage my blood sugar levels?

Lifestyle choices can often help you manage your blood sugar levels. Eating a healthy diet with plenty of fruit and vegetables, maintaining a healthy weight, and getting regular exercise can help. Other tips for controlling blood sugar include:

  • Keeping a log of your blood sugar readings from your monitor.
  • Eating at regular times and not skipping meals.
  • Choosing foods lower in calories, saturated fat, trans fat, sugar, and salt.
  • Tracking your food, drink, and exercise (for weight management and blood sugar control).
  • Drinking water instead of juice and soda.
  • Limiting alcohol—too much can cause low blood sugar.
  • For a sweet treat, choosing fruit instead of a candy bar.
  • Using food portion control (for example, filling your plate Cdc-pdf[PDF – 14MB] with one-fourth meat or other protein, one-fourth starchy foods, and one-half non-starchy vegetables.

Keep a record of your blood sugar numbers to see what makes your levels go up or down. Your doctor, dietitian, and health care team will help guide you in how to live healthier to prevent serious health problems. Talk to your health care team for more information about diabetes and blood sugar.

What if I can’t pay for tests and diabetes supplies?

Medicare, Medicaid, and most private insurance plans pay for the A1C test and some of the cost of supplies for checking your blood sugar. Check your plan or ask your health care team for help finding low-cost or free supplies. Also ask what to do if you run out of test strips. Visit the MedicareExternal website to learn more about diabetes tests and supplies.

Page last reviewed: March 4, 2019