How Long Does it Take to Lower Blood Sugar Spikes? A Guide

A blood sugar spike may happen at some point in your weight loss journey, typically after eating carbs. Your body will respond to bring your glucose levels down to a normal range, but how long will it take?

Julia Zakrzewski, RD
— Signos
Health & Nutrition Writer
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Updated by

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Science-based and reviewed

July 24, 2024
July 28, 2022
— Updated:
June 23, 2023

Table of Contents

Just as individuals can have different blood glucose reactions to eating the same food, your body’s ability to clear excess sugar out of the bloodstream varies depending on whether you have diabetes, prediabetes, or no diabetes. 

In general, to help lower blood sugar faster, you can increase physical activity and refrain from eating foods with refined carbohydrates. It’s also important to understand the long-term health implications of living with high blood sugar.

Why Blood Sugar Spikes

After eating, the digestive system breaks down carbohydrates into simple sugar molecules called glucose, which are absorbed into your bloodstream. Certain foods are digested more slowly than others and will cause a gradual increase in your blood sugar. 

On the other hand, meals that are low in fiber and high in refined carbs and sugars cause a rapid increase of sugar molecules in the bloodstream. This influx of glucose leads to a sugar spike (hyperglycemia).  

High blood sugar levels prompt the pancreas to release insulin, a hormone that regulates blood glucose levels. Insulin clears glucose from the bloodstream and moves it into cells, where some are used for energy. Excess glucose is stored in the liver, muscles, and fat tissues as energy reserves.

What Are Triggers of Blood Sugar Spikes?

Blood sugar spikes are completely normal and can happen for a variety of reasons that could be related to food choices or other elements impacting your physical and mental health. The ultimate goal is to stay within your target glucose range for 80% of the day and minimize the size of a glucose spike.  


According to the Centers for Disease Control (CDC), smoking can increase the risk of developing type 2 diabetes. In fact, smokers are 30% to 40% more likely to be diagnosed with type 2 diabetes than non-smokers.8 Nicotine naturally increases blood sugar levels by changing chemical processes in cells to ensure they do not respond to insulin, leading to insulin resistance. Nicotine can also trigger the production of triglycerides, a type of fat linked to insulin resistance. 

Not Brushing and Flossing

Brushing your teeth and flossing should be a staple hygiene habit and for good reason. Skipping this step in your routine could lead to gum disease or gingivitis, which is more common in people living with diabetes. This infection can cause blood sugar levels to spike since the body’s immune system is heightened to fight pathogens. This will make it more difficult for the body to maintain optimal insulin and blood sugar levels.

The American Dental Association (ADA) recommends brushing teeth for two minutes twice a day and replacing toothbrushes every three to four months. Dentist visits should be twice a year or every six months.9 

Ultra-processed foods

Ultra-processed foods are very low in fiber and very high in sugars. Examples of ultra-processed foods include anything deep-fried, white bread products, non-diet soft drinks, french fries, baked goods, and candy. 

Added sugars

Sugars, such as corn syrup, are often added to food for flavor and sweetness, but they also help with the browning and texture of baked goods. Sometimes, they can help make nutrient-dense foods more enjoyable. 

While sweetened beverages and baked goods are the most frequently consumed sources of added sugars, you may also find them in unexpected places like breakfast bars, condiments, sauces, and yogurt. 

Added sugars are now listed on nutrition labels, making it easier to see what you eat. Compare labels and choose those that are lower in added sugars. Aim for no more than a few grams per serving.


If you’re under the weather, you may have more than just that cold to worry about. In addition to giving you symptoms like fatigue and pain, infections can increase your blood sugar. When you come down with an illness like a cold or the flu, your body leaps into action, emitting a stress response that allows it to recruit the proper immune cells and enable them to fight off the pathogen.

Recovering from surgery

Surgery, even outpatient procedures, can put the body under an immense amount of stress. This, coupled with anesthesia, can lead to increased blood glucose levels. People living with diabetes should speak to their healthcare team about possible blood sugar complications following a procedure. 

Being dehydrated

Hydration is essential to overall wellness, weight loss, and diabetes management. When dehydrated, the bloodstream is filled with less fluid and more glucose, which could lead to a spike in blood sugar levels. 

Talk with your doctor about how much water you should drink each day. Before recommending a target number, they’ll consider factors such as your ongoing health conditions, weight, activity level, and more.

Certain medications

Some medications could increase your blood sugar levels and could vary from person to person. Specific medications that have been found to increase glucose in the human body include diuretics (water pills), certain medications treating depression, and blood pressure medications.

Before changing your medication routine, speak to your healthcare provider to discuss alternative options and possible risks. 

Chronic stress

Epinephrine, cortisol, growth hormone, and glucagon—the stress hormones—work together to release glucose into your bloodstream, among other changes. These changes help you stay sharp, focused, and give you extra energy. Your adrenal glands release adrenaline and cortisol to encourage your liver to produce more glucose. These interconnected processes will cause your blood sugar levels to naturally spike during stressful situations

woman in workout clothes stretching and looking at her smartphone
Over time, chronically high blood sugar levels can lead to blood vessel and nerve damage.

How Long Does it Take to Lower Blood Sugar Spike?

Blood sugar spikes can be accompanied by symptoms such as headache and ringing in your ears, which is called tinnitus, but many people don’t feel any symptoms at all. 

The American Diabetes Association has found that people who live with diabetes and prediabetes take longer to bring high blood sugar levels back down to normal compared to people without diabetes.4


People Without Diabetes 

If you do not have diabetes, your body’s insulin will naturally bring down your blood sugar. It is expected that most people will see their glucose levels return to normal within two hours after eating.3

Exercise can help bring down blood sugar faster, but it is normal for insulin to take two hours to complete its cycle and successfully move surplus sugar out of your bloodstream.

People With Prediabetes

Prediabetes is a condition marked by high blood sugar, but not levels high enough to be called diabetes. People with prediabetes have lost some ability to clear the sugar out of the bloodstream, though in most cases, blood sugar can be managed through lifestyle and diet modifications. 

For individuals with prediabetes, how long it takes to bring down a blood sugar spike can vary widely based on:

  • How much insulin their body is able to produce
  • What kind of food they ate
  • How much sugar they ate
  • Muscle mass

Getting some exercise after eating, even a light stroll or some chores around the house, can help bring blood sugar down more quickly.

People With Type 2 Diabetes 

People diagnosed with type 2 diabetes still have some insulin, but they’ve lost the ability to successfully clear extra sugar out of the bloodstream.3

Depending on the progression and severity of type 2 diabetes, insulin medication may be needed to help bring blood sugar down. Blood sugar spikes treated with fast-acting insulin can normalize blood glucose numbers within 15 minutes.

People With Type 1 Diabetes 

People diagnosed with type 1 diabetes were born without the ability to produce their own insulin and require insulin medication. 

Many patients use an insulin pump which releases doses throughout the day to keep blood sugar stable. If blood sugar spikes after eating a meal, it may be necessary to take fast-acting insulin, which takes around 15 minutes to start working.

Anyone diagnosed with diabetes or prediabetes should follow the care plan provided by their doctor.

woman relaxing in a hammock
Avoiding refined carbs and cultivating healthy habits like getting enough sleep, exercise, reducing stress can help prevent spikes in blood sugar.

How Blood Sugar Spikes Can Impact Overall Health 

Some people are less able to efficiently clear excess sugar from their bloodstream and need to be very careful with their diet and lifestyle choices. 

One blood sugar spike should not have long-term implications for your health. However, continuously high levels of sugar in your blood will increase your risk of diabetes, heart disease, and unhealthy weight gain.

Chronic high blood sugar in people with diabetes can result in diabetic ketoacidosis,  a life-threatening condition that presents with shortness of breath, fruity breath, nausea, vomiting, and fainting.3

9 Things You Can Do to Reduce Blood Sugar Spikes

Frequent blood sugar spikes can have unpleasant side effects, including fatigue, hunger, and moodiness. For people without diabetes, simple lifestyle changes are the best way to prevent blood sugar spikes from happening as often and reap the benefits of stable blood sugar.

Keep track of blood sugar levels

Tracking your glucose can allow you to discover irregularities in your body’s processing of glucose, learn what causes your glucose to spike, and whether your glucose levels fall into average ranges. 

Cut back on carbohydrate intake

Carbohydrates tend to raise blood glucose levels more than other foods; however, a low-carb eating style may help a person stabilize and manage their blood sugars. Before reducing carb intake, make sure to consult a healthcare professional or a dietitian to ensure this dietary style works well for your body.

Choose to eat carbohydrates that are good for your body

Choosing slow-carb foods and foods with a low glycemic index will have a delayed impact on your blood glucose. These foods are also rich in fiber, minerals, and nutrients and promote stable blood sugars and health overall.

Stay within your moderate weight range

The ideal weight range for a person varies among individuals, but a doctor can help provide guidance for your specific situation.

Studies note a link between obesity and type 2 diabetes.10 Research also highlights the relationship between obesity and insulin resistance.11 Oftentimes, losing between five and 10% of overall body weight can help those with excess weight improve their blood sugar levels.

Manage your portion sizes

Various factors can influcuence ideal portion sizes for an individual. As a general guideline, the US Department of Agriculture recommends the following:14

  • Half of your plate should include fruits and non-starchy vegetables
  • Half your grain choices should be whole grains
  • Dairy should be low-fat or fat-free
  • Include protein with every meal

Exercise on a regular basis

Physical activity can help lower blood sugar and resolve blood sugar spikes. Your muscles rely on glucose for fuel, so the more you use your muscles, the more fuel they will burn. The American College of Sports Medicine (ACSM) and the U.S. Department of Health and Human Services Physical Activity Guidelines jointly recommend the following:12,13

  • Exercise at a moderate intensity for 30 minutes a day, five days a week, for a total of 150 minutes of exercise per week.
  • Exercise at a vigorous intensity for a minimum of 20 minutes, three days per week, for a total of 60 to 75 minutes per week.
  • Do a combination of moderate and vigorous-intensity walking.

Stay hydrated

Water plays a crucial role in maintaining the healthy function of many biological systems in the body, including those involved in blood sugar control. So, does drinking water lower blood sugar? Well, water flushes our system, so it can actually help remove excess blood glucose.15

Increased water intake allows the kidneys to process and flush excess glucose out through our urine which ultimately helps prevent blood sugar levels from trending high. Meeting our hydration needs can also help prevent overeating, proactively preventing blood sugar spikes.

Keep your stress levels under control

Your body's stress response floods it with chemicals and hormones to cause a surge of glucose into your bloodstream to provide your muscles with enough energy to face or flee from your stressor. In the modern world, this response isn’t very helpful. Managing stress effectively can stabilize and even reduce your blood pressure and blood sugar. Too much chronic stress can increase your risk of prediabetes and other serious health conditions.

Get the right amount of sleep

Your brain does not shut down when you go to sleep. During sleep, the brain and body get rid of waste, release hormones, recharge cells, and work on learning and memory. Disrupted or insufficient sleep increases your risk of insulin resistance, prediabetes, type 2 diabetes, metabolic syndrome, obesity, high blood pressure, abnormal blood lipids, and heart disease. Even one night of sleep deprivation can increase insulin resistance and the risk of developing prediabetes.16 Aim for 7 to 8 hours of restful sleep each night.

Why Managing Blood Sugar is Key to Overall Health

Some people are less able to efficiently clear excess sugar from their bloodstream and need to be very careful with their diet and lifestyle choices. 

One blood sugar spike should not have long-term implications for your health. However, continuously high levels of sugar in your blood will increase your risk of diabetes, heart disease, and unhealthy weight gain.

Chronic high blood sugar in people living with diabetes can result in diabetic ketoacidosis,  a life-threatening condition that presents with shortness of breath, fruity breath, nausea, vomiting, and fainting.3

When to Reach Out for Medical Assistance

You should speak to your healthcare provider to determine what range you should aim for, especially if you are living with prediabetes or diabetes. General guidelines are:

  • 140 mg/dL is considered hyperglycemic
  • 180 mg/dL is considered high
  • 240 mg/dL is life-threatening and could put the individual at risk for diabetes ketoacidosis (DKA)
  • 600 mg/dL or higher can cause potentially fatal hyperglycemic hyperosmolar syndrome (HHS)

If you experience any of the below symptoms, you should call 911 or go directly to an emergency room for assistance:

  • Hyperglycemia and high ketone levels
  • Sustained high blood glucose levels
  • DKA or SHA symptoms
  • Two high blood glucose values of 300 mg/dL or higher
  • Blood glucose levels above 180 mg/dL (or target range) over one week

You should contact your medical provider if you have:

  • Ongoing elevated blood glucose
  • Frequently urinating
  • Increased thirst

Main Takeaways 

Without a diagnosis of prediabetes or diabetes, it should take one to two hours for a blood sugar spike to come down. You can opt for a walk or a workout to accelerate the process. 

A continuous glucose monitor (CGM) device can provide you with personalized insight into what causes blood sugar spikes. This data can help you prevent future spikes and empower you to make diet and lifestyle choices that align with your blood sugar goals. 

One high blood sugar reading should not have a significant impact on your overall health and weight loss goals. However, if your glucose levels are consistently trending upward, you should connect with your doctor to discuss the risk of long-term implications.

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Topics discussed in this article:


  1. Mifsud, S., Schembri, E. L., & Gruppetta, M. (2018). Stress-induced hyperglycaemia. British Journal of Hospital Medicine, 79(11), 634–639. 
  2. Clore, J. N., & Thurby-Hay, L. (2009). Glucocorticoid-Induced Hyperglycemia. Endocrine Practice, 15(5), 469–474. 
  3. Hyperglycemia (High Blood Glucose) | ADA. (n.d.). American Diabetes Association. Retrieved July 2022, from 
  4. Association, A. D. (2001). Postprandial Blood Glucose. Diabetes Care, 24(4), 775–778. 
  5. Yu, K., Ke, M. Y., Li, W. H., Zhang, S. Q., & Fang, X. C. (2014). The impact of soluble dietary fibre on gastric emptying, postprandial blood glucose and insulin in patients with type 2 diabetes. Asia Pacific journal of clinical nutrition, 23(2), 210–218. 
  6. Campbell, A. P., & Rains, T. M. (2014). Dietary Protein Is Important in the Practical Management of Prediabetes and Type 2 Diabetes. The Journal of Nutrition, 145(1), 164S-169S. 
  7. Campbell, A. P., & Rains, T. M. (2014b). Dietary Protein Is Important in the Practical Management of Prediabetes and Type 2 Diabetes. The Journal of Nutrition, 145(1), 164S-169S.
  8. Centers for Disease Control and Prevention. (2022, June 20). Smoking and diabetes. Smoking and Diabetes.
  9. Home oral care. American Dental Association. (n.d.).
  10. Klein, S., Gastaldelli, A., Yki-Järvinen, H., & Scherer, P. E. (2022). Why does obesity cause diabetes? Cell Metabolism, 34(1), 11–20. 
  11. Jiang, J., Cai, X., Pan, Y., Du, X., Zhu, H., Yang, X., Zheng, D., Gaisano, H., Wei, T., & He, Y. (2020). Relationship of obesity to adipose tissue insulin resistance. BMJ Open Diabetes Research & Care, 8(1). 
  12. American College of Sports Medicine. Trending Topic | Physical Activity Guidelines. Accessed July 21, 2022.
  13. U.S. Department of Health and Human Services. 2008 Physical Activity  Guidelines for Americans. Accessed July 21, 2022.
  15. Water and Diabetes. (2019, January 15). Retrieved December 15, 2022.
  16. Donga E, van Dijk M, van Dijk JG, et al. A Single Night of Partial Sleep Deprivation Induces Insulin Resistance in Multiple Metabolic Pathways in Healthy Subjects. The Journal of Clinical Endocrinology & Metabolism. 2010;95(6):2963-2968. doi:10.1210/jc.2009-2430

About the author

Julia Zakrzewski is a Registered Dietitian and nutrition writer. She has a background in primary care, clinical nutrition, and nutrition education. She has been practicing dietetics for four years.

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