Table of ContentsView AllTable of ContentsPurpose of TestingPostprandial Glucose TestGlucose MonitoringGoals of MonitoringWhen to See a Provider
Table of ContentsView All
View All
Table of Contents
Purpose of Testing
Postprandial Glucose Test
Glucose Monitoring
Goals of Monitoring
When to See a Provider
Postprandial glucoseis the name for the level ofglucose(sugar) in your blood after eating, which tends to spike one hour after eating and return to normal within two hours.
There are different ways to measure this, including a two-hour postprandial glucose (PPG) test, an oral glucose challenge, and a device called aglucometer. These tests can either help diagnose diabetes or determine if you’re taking the right amount ofinsulinwith meals.
Meaning of Normal and Abnormal Blood Sugar After Eating
Glucose is your body’s main source of energy, which you obtain fromcarbohydratesyou eat. Insulin is the hormone that regulates this process and helps move glucose into cells for fuel. Any unused glucose is converted into a form calledglycogenand stored in the liver.
Under normal circumstances,blood sugar levelsrise after you eat and fall again as cells take up glucose. Within two hours of eating, your insulin and blood sugar levels should return to normal.
However, if blood sugar levels don’t fall as much as they should, it could be a sign oftype 2 diabetesorprediabetes.
On the other hand, if you have diabetes, high postprandial blood sugar may be a sign that you are not managing your condition or the condition is getting worse.
Different tests and tools are available to measure postprandial blood sugar. Some are used for diagnostic purposes, while others are used to manage and monitor diabetes.
Two-Hour Postprandial Glucose Test
A two-hour postprandial glucose (PPG) test is a simple blood test used to measure the amount of glucose in your blood after eating. It involves measuring your blood sugar before and after drinking a controlled amount of a sugary solution.
Why the Test Is Used
Also known as anoral glucose tolerance test (OGTT), the two-hour PPG can determine whether you have prediabetes, type 2 diabetes, orgestational diabetes(a form of the disease affecting roughly 10% of people with pregnancy).
The PPG test may be recommended if you havesymptoms of diabetes, like:
How the Test Is Performed
The two-hour PPG test is performed after a minimum of eight hours of fasting. The test is relatively easy to perform and involves three simple steps:
An abbreviated version of the test, called an oral glucose challenge, is used for gestational diabetes. The test, routinely done between weeks 24 and 28 weeks of pregnancy, also involves three steps:
What the Results Mean
The two-hour PPG and oral glucose challenge are both used for diagnostic purposes. The results are typically described in milligrams per deciliter (mg/dL) but are sometimes measured in millimoles per liter (mmol/L).
If results are inconclusive or borderline, your healthcare provider may recommend a three-hour PPG in which you are provided three sugary solutions and your blood is tested four times. The results of the three-hour test are especially useful in diagnosing gestational diabetes.
Aglucometeris a simple device used to monitor your blood glucose levels if you havetype 1 diabetes, type 2 diabetes, or gestational diabetes.
A glucometer is a self-test commonly used in people with diabetes. It is especially useful if you have type 1 diabetes (the type in which thepancreasmakes little or no insulin) or are taking insulin to control your blood sugar.
A glucometer can be used to:
Depending on your condition, you may need to monitor your blood sugar as few as two times a day to as much as 10 times a day.
Testing should be done two hours after a meal. This information can help you and your provider assess if you need to change your insulin or medication doses.
This may include testing yourself:
There are alsocontinuous glucose monitorsthat provide real-time readings 24 hours a day and can alert you if your blood sugar is too high or too low.
Normal postprandial blood sugar levels vary based on the type of diabetes you have and whether or not you use insulin. Normal levels are currently described as follows, measured in milligrams per deciliter (mg/dL):
GroupNormal readingAdults without diabetesUnder 140 mg/dL two hours after eatingAdults with type 1 or 2 diabetesUnder 180 mg/dL two hours after eatingAdults with type 1 or 2 diabetes who take mealtime insulinUnder 180 mg/dL two hours after eatingAdults with type 1 or 2 diabetes not taking mealtime insulinUnder 140 mg/dL two hours after eatingPregnant adults with gestational diabetesUnder 140 mg/dL one hour after eating, and 120 mg/dL two hours after eatingPregnant adults with preexisting type 1 or 2 diabetesUnder 110 to 140 mg/dL one hour after eating, and under 100 to 120 mg/dL two hours after eatingChildren and teens under 18 with type 1 or 2 diabetesUnder 200 mg/dL one hour after eating, and under 180 mg/dL two hours after eatingBased on the results, you may need to take steps to bring down your blood sugar if they are high. This includes takingfast-acting insulinor exercising to burn off excess glucose.If levels are too low, you may need to eat or drink 15 grams of a fast-acting carbohydrate, such as three or four glucose tablets, four or five hard candies, or a 1/2 cup of fruit juice.What Is the Best Time to Check Blood Sugar?Why Monitoring Blood Sugar Is ImportantFor people with diabetes, postprandial blood glucose monitoring along withfasting blood glucosemonitoring—meaning your blood sugar levels when you haven’t eaten—are important parts of diabetes management.If left uncontrolled, chronic high blood sugar levels can start to damage multiple organ systems, leading to complications like:Diabetic neuropathy(diabetic nerve damage)Diabetic nephropathy(diabetic kidney disease)Diabetic retinopathy(diabetic vision damage)Increased risk of heart attack and strokeFoot damageSkin and mouth infectionsHearing lossBlood glucose monitoring helps you determine the appropriate strategy for controlling your blood sugar and avoiding these complications. This not only includes the use of insulin and diabetes medications but also lifestyle choices like diet and the foods you eat.Role of Diet and ExerciseIf you have diabetes, foods with a highglycemic index (GI)—meaning those that are rapidly digested and cause your blood sugar to spike—may need to be limited or entirely avoided in favor of foods with a low GI.Here are just a few examples to consider:High GI Food to AvoidWhite riceWhite breadPotatoesCornflakesBeetsPuffed rice cakesWatermelonIce creamLow GI Food to EatBrown riceWhole-grain breadSweet potato, squashSteel cut oatsBroccoliTree nuts, peanutsApples, orangesLow-fat yogurtSimilarly, getting a minimum of 150 minutes of moderate-intensity exercise each week can help you better manage your diabetes. Moderate-intensity exercises are those—like brisk walking, jogging, swimming, dancing, or cycling—where you can talk during the workout but not sing.The American Diabetes Association recommends that you break up your 150-minute weekly target into increments, such as 50 minutes of exercise three times a week, 30 minutes five times a week, or 25 minutes six times a week. Avoid going longer than 48 hours between workouts to reap the optimal benefits.When to See a Healthcare ProviderPeople experience diabetes in different ways, and some may not even realize they have it until complications develop. This is why you need to to act if you suspect you have diabetes as it can lead to serious health concerns likevision loss,kidney disease, andstrokeif left untreated.Some common and uncommon signs of diabetes include:Skin problems: Including wounds that won’t heal, recurrent skin infection, white patches or sores in your mouth, andskin discolorationin the armpits or groinChanges in vision: Including blurred vision, increased floaters, chronic eye pain, and light sensitivityDigestive and urinary problems: Including increased hunger or thirst, frequent urination, trouble swallowing, and unintended weight lossOther health concerns: Including persistent fatigue andtingling or pins-and-needles sensationsin the hands and feetIf you are being treated for diabetes and have difficulty managing your blood sugar, see your provider. You may need an adjustment in your medications or changes in your diet or lifestyle to achieve tighter control.SummaryPostprandial blood sugar is the level of glucose in your blood after eating. It tends to spike one hour after eating and normalize one hour later.Postprandial blood sugar can be measured with a postprandial glucose (PPG) test to determine if you have prediabetes (140 to 199 mg/dL), type 2 diabetes (200 mg/dL and over), or gestational diabetes (190 mg/dL and over).Postprandial blood sugar can also be monitored in people with type 1, type 2, or gestational diabetes using a device called a glucometer. The self-test can determine whether you are taking enough insulin with meals or need an adjustment in your diet or medications.What is a Dangerous Blood Sugar Level?
Based on the results, you may need to take steps to bring down your blood sugar if they are high. This includes takingfast-acting insulinor exercising to burn off excess glucose.
If levels are too low, you may need to eat or drink 15 grams of a fast-acting carbohydrate, such as three or four glucose tablets, four or five hard candies, or a 1/2 cup of fruit juice.
What Is the Best Time to Check Blood Sugar?
Why Monitoring Blood Sugar Is Important
For people with diabetes, postprandial blood glucose monitoring along withfasting blood glucosemonitoring—meaning your blood sugar levels when you haven’t eaten—are important parts of diabetes management.
If left uncontrolled, chronic high blood sugar levels can start to damage multiple organ systems, leading to complications like:
Blood glucose monitoring helps you determine the appropriate strategy for controlling your blood sugar and avoiding these complications. This not only includes the use of insulin and diabetes medications but also lifestyle choices like diet and the foods you eat.
Role of Diet and Exercise
If you have diabetes, foods with a highglycemic index (GI)—meaning those that are rapidly digested and cause your blood sugar to spike—may need to be limited or entirely avoided in favor of foods with a low GI.
Here are just a few examples to consider:
High GI Food to AvoidWhite riceWhite breadPotatoesCornflakesBeetsPuffed rice cakesWatermelonIce creamLow GI Food to EatBrown riceWhole-grain breadSweet potato, squashSteel cut oatsBroccoliTree nuts, peanutsApples, orangesLow-fat yogurt
High GI Food to AvoidWhite riceWhite breadPotatoesCornflakesBeetsPuffed rice cakesWatermelonIce cream
White rice
White bread
Potatoes
Cornflakes
Beets
Puffed rice cakes
Watermelon
Ice cream
Low GI Food to EatBrown riceWhole-grain breadSweet potato, squashSteel cut oatsBroccoliTree nuts, peanutsApples, orangesLow-fat yogurt
Brown rice
Whole-grain bread
Sweet potato, squash
Steel cut oats
Broccoli
Tree nuts, peanuts
Apples, oranges
Low-fat yogurt
Similarly, getting a minimum of 150 minutes of moderate-intensity exercise each week can help you better manage your diabetes. Moderate-intensity exercises are those—like brisk walking, jogging, swimming, dancing, or cycling—where you can talk during the workout but not sing.
The American Diabetes Association recommends that you break up your 150-minute weekly target into increments, such as 50 minutes of exercise three times a week, 30 minutes five times a week, or 25 minutes six times a week. Avoid going longer than 48 hours between workouts to reap the optimal benefits.
When to See a Healthcare Provider
People experience diabetes in different ways, and some may not even realize they have it until complications develop. This is why you need to to act if you suspect you have diabetes as it can lead to serious health concerns likevision loss,kidney disease, andstrokeif left untreated.
Some common and uncommon signs of diabetes include:
If you are being treated for diabetes and have difficulty managing your blood sugar, see your provider. You may need an adjustment in your medications or changes in your diet or lifestyle to achieve tighter control.
Summary
Postprandial blood sugar is the level of glucose in your blood after eating. It tends to spike one hour after eating and normalize one hour later.
Postprandial blood sugar can be measured with a postprandial glucose (PPG) test to determine if you have prediabetes (140 to 199 mg/dL), type 2 diabetes (200 mg/dL and over), or gestational diabetes (190 mg/dL and over).
Postprandial blood sugar can also be monitored in people with type 1, type 2, or gestational diabetes using a device called a glucometer. The self-test can determine whether you are taking enough insulin with meals or need an adjustment in your diet or medications.
What is a Dangerous Blood Sugar Level?
13 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Diabetes Association Professional Practice Committee.Diagnosis and classification of diabetes: Standards of Care in Diabetes—2024.Diabetes Care. 2024;47(Suppl 1):S20-S42. doi:10.2337/dc24-S002MedlinePlus.Blood sugar.American Diabetes Association.Gestational diabetes.National Institute of Diabetes and Digestive and Kidney Diseases.Know your blood sugar numbers: use them to manage your diabetes.Centers for Disease Control and Prevention.What is type 1 diabetes?Mount Sinai.Home blood sugar testing.Centers for Disease Control and Prevention.Monitoring your blood sugar.National Institute of Diabetes and Digestive and Kidney Diseases.Continuous glucose monitoring.Diabetes UK.Complications of diabetes.Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.Am J Clin Nutr.2021 Nov 8;114(5):1625-1632. doi:10.1093/ajcn/nqab233American Diabetes Assocation.Weekly exercise targets.U.S. Centers for Disease Control.Prevent diabetes complications.American Diabetes Association.About diabetes: warning signs and symptoms.
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Diabetes Association Professional Practice Committee.Diagnosis and classification of diabetes: Standards of Care in Diabetes—2024.Diabetes Care. 2024;47(Suppl 1):S20-S42. doi:10.2337/dc24-S002MedlinePlus.Blood sugar.American Diabetes Association.Gestational diabetes.National Institute of Diabetes and Digestive and Kidney Diseases.Know your blood sugar numbers: use them to manage your diabetes.Centers for Disease Control and Prevention.What is type 1 diabetes?Mount Sinai.Home blood sugar testing.Centers for Disease Control and Prevention.Monitoring your blood sugar.National Institute of Diabetes and Digestive and Kidney Diseases.Continuous glucose monitoring.Diabetes UK.Complications of diabetes.Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.Am J Clin Nutr.2021 Nov 8;114(5):1625-1632. doi:10.1093/ajcn/nqab233American Diabetes Assocation.Weekly exercise targets.U.S. Centers for Disease Control.Prevent diabetes complications.American Diabetes Association.About diabetes: warning signs and symptoms.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
American Diabetes Association Professional Practice Committee.Diagnosis and classification of diabetes: Standards of Care in Diabetes—2024.Diabetes Care. 2024;47(Suppl 1):S20-S42. doi:10.2337/dc24-S002MedlinePlus.Blood sugar.American Diabetes Association.Gestational diabetes.National Institute of Diabetes and Digestive and Kidney Diseases.Know your blood sugar numbers: use them to manage your diabetes.Centers for Disease Control and Prevention.What is type 1 diabetes?Mount Sinai.Home blood sugar testing.Centers for Disease Control and Prevention.Monitoring your blood sugar.National Institute of Diabetes and Digestive and Kidney Diseases.Continuous glucose monitoring.Diabetes UK.Complications of diabetes.Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.Am J Clin Nutr.2021 Nov 8;114(5):1625-1632. doi:10.1093/ajcn/nqab233American Diabetes Assocation.Weekly exercise targets.U.S. Centers for Disease Control.Prevent diabetes complications.American Diabetes Association.About diabetes: warning signs and symptoms.
American Diabetes Association Professional Practice Committee.Diagnosis and classification of diabetes: Standards of Care in Diabetes—2024.Diabetes Care. 2024;47(Suppl 1):S20-S42. doi:10.2337/dc24-S002
MedlinePlus.Blood sugar.
American Diabetes Association.Gestational diabetes.
National Institute of Diabetes and Digestive and Kidney Diseases.Know your blood sugar numbers: use them to manage your diabetes.
Centers for Disease Control and Prevention.What is type 1 diabetes?
Mount Sinai.Home blood sugar testing.
Centers for Disease Control and Prevention.Monitoring your blood sugar.
National Institute of Diabetes and Digestive and Kidney Diseases.Continuous glucose monitoring.
Diabetes UK.Complications of diabetes.
Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.Am J Clin Nutr.2021 Nov 8;114(5):1625-1632. doi:10.1093/ajcn/nqab233
American Diabetes Assocation.Weekly exercise targets.
U.S. Centers for Disease Control.Prevent diabetes complications.
American Diabetes Association.About diabetes: warning signs and symptoms.
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