If you find yourself fatigued and sluggish right after eating a big meal, drawn towards the comfort of your bed or a large sofa to slump into, your body might be suggesting that you take a look at the levels of your postprandial (post-mealtime) blood sugar. An exaggerated escalation in blood sugar following a meal is referred to as postprandial hyperglycemia.
- The hours immediately following a meal can provide a more accurate and telling time frame in which to understand metabolic health. Our body goes through 3 metabolic periods based on the entry and presence of glucose in the bloodstream – postprandial, post-absorptive and fasted,
- Postprandial blood sugar levels exceeding the ideal range can lead to prediabetes or diabetes,
- To sit or lie down after a meal can adversely affect glucose levels. Another way to slow down digestion and control postprandial levels is to engage in 10 minutes of low-intensity activity such as walking.
A primer on postprandial blood glucose
The carbohydrates in the food you eat are processed and broken down into simple sugars, glucose and fructose, which then enter the bloodstream. This provides cells all over your body with energy to function efficiently. Our body responds by releasing insulin, a hormone that keeps blood sugar levels in control. It must be kept in mind that the regular recurrence of blood sugar levels remaining elevated for a long period is not normal. It indicates that the body is failing to extract glucose from the bloodstream or has developed insulin resistance.
The hours immediately following a meal can provide a more accurate and telling time frame in which to understand metabolic health. Our body goes through the following 3 metabolic periods based on the entry and presence of glucose in the bloodstream:
- Postprandial, the 4 hours following a meal during which blood glucose levels are increased. If a person has 3 meals a day, they spend about half their day in the postprandial phase.
- Post-absorptive, between 4 and 6 hours after a meal, when the liver begins breaking down glycogen.
- Fasted, around 10–12 hours after the final meal of the day, when the body no longer has carbohydrates to break down for glucose and depends on other sources such as lactate instead.
Glucose levels can be monitored at home using devices called glucometers—over-the-counter machines that use a small drop of blood, received through a pinprick on the finger, to analyse the levels of blood sugar, usually after 30 minutes or an hour. However, continuous glucose monitors (CGM), with a sensor underneath the skin sending data on glucose levels 24 hours a day, provide more frequent data-points and offer a better idea of the real-time fluctuations of glucose levels.
Why should you keep an eye on post-meal blood sugar spikes?
Keeping a close eye on glucose levels in the blood becomes significant in terms of spotting signs of postprandial hyperglycemia—the accumulation of high amounts of glucose—which can in turn lead to an increased risk of strokes, cardiac disease, infections and nerve damage and also affect vital organs if not kept in check.
Postprandial blood sugar levels exceeding the ideal range can lead to prediabetes or diabetes. This makes watching glucose levels essential for those who are at risk of diabetes, or those already contending with it. For a person who isn’t afflicted, the International Diabetes Federation in Brussels, Belgium, recommended in its 2011 guidelines that the postprandial blood sugar levels in the 2 hours following a meal should remain under 160 milligrams per decilitre (mg/dL), but modified the diagnostic criteria to >200 mg/dL.
However, research indicates that, ideally, the benchmark levels should remain much lower. A recent study that used CGMs to monitor the blood sugar values of non-obese, non-pregnant, healthy, non-diabetic children (aged 6 and older) and adults found that the mean average glucose value was 98–99 mg/dL for all age groups except those over 60 years, for whom it was 104 mg/dL.
There are further medical reasons why keeping an eye on blood sugar spikes and crashes is important, beyond the risks of postprandial hyperglycemia and insulin resistance, and even beyond the scope of type 2 diabetes. Research has shown that postprandial blood glucose is a better predictor for cardiovascular events (a marker of metabolic health) in type 2 diabetes and atherosclerosis rather than fasting glucose, especially in women. Thus, postprandial blood sugar serves as a better indicator of how the body behaves with the food it consumes and provides better insights into the state of one’s metabolic health and the risk of diabetes they face. It holds a similar advantage over the glycosylated hemoglobin (HbA1c) test, which only shows the average blood sugar over the course of 3 months.
Post-meal hyperglycemia also leads to oxidative stress, a precursor to inflammation in the body. Postprandial blood sugar is thus correlated with inflammatory conditions like Alzheimer’s disease. (
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Additionally, there is also value to be found in postprandial glucose testing for those seeking a more incisive understanding of the way their body reacts to the food they consume and how successfully their body is able to metabolize it. Since each body reacts differently to the food that enters it, gaining a window into what foods can potentially be detrimental to metabolic health—as well as those that are beneficial—is an important step to take. Studies indicate that while the effect of one kind of food on postprandial glucose can vary from one person to another, an individual is likely to react to that food in a similar manner every time they eat it. This makes it a compelling argument to gauge dietary needs on a case-by-case basis, rather than by subscribing to any form of widespread, standardized nutrition ideals.
Ways to manage post-meal blood sugar spikes
One of the most impactful ways to regulate postprandial glucose spikes is through exercise. An analysis of research data shows that physical exercise shows evidence of improving blood sugar levels in exercise interventions in both the short term (less than or equal to 2 weeks) and the long term (greater than 2 months). Exercise can help preferential glucose uptake, improved glucose disposal and enhanced insulin action by triggering the transportation of additional glucose transporters to our muscle cells.
Staying active after meals
To sit or lie down after a meal can adversely affect glucose levels. Another way to slow down digestion and control postprandial levels is to engage in 10 minutes of low-intensity activity such as walking, taking the stairs, household chores or some movement in the first 45 minutes following a meal. However, the timing of this activity is significant, as exercising too soon after a meal is ineffective in blunting post-meal glucose spikes.
Understanding what and when to eat is an important aspect of keeping tabs on postprandial blood sugar. Since carbohydrates are what lead to increases in glucose, the largest crests and valleys in blood sugar levels are often the result of the consumption of sugar, white flour, etc. An often-overlooked fact is that the order in which foods in a meal are consumed can also influence postprandial levels—for instance, having fats or proteins before carbohydrates has been shown to dull glucose spikes.
Eat some cheese, an egg or yoghurt before your meal for improved glycemic control. Beans, vegetables, fruits and whole grains belong to a group of foods that do not cause a sudden, sharp increase in your blood sugar (meaning they have a low glycemic index) and should become a staple of your diet. In the same vein, foods with a higher glycemic index, such as white rice, white bread and potatoes, should be avoided.
Splitting up meals can also help with preventing spikes in glucose. Rather than having 1 large meal for lunch, for example, it would be prudent to eat a small salad or bowl of fruits as a mid-morning snack, then a half-sized plate of lunch and have a sandwich or save desserts for later in the afternoon. This can quell both the spikes of postprandial glucose as well as the urge to eat bigger meals throughout the day.
Food as medicine
Research postulates that vinegar slows gastric emptying, which enables the body to slow the breaking down and absorption of carbohydrates into glucose, helping to flatten the glucose spike. About 1–1.5 tablespoons of vinegar, in all its varieties from balsamic vinegar to apple cider, can keep a check on postprandial levels. Adding fermented food to your diet is another way to reap the benefits.
Cinnamon, too, can help regulate glucose by increasing insulin sensitivity and reducing blood sugar. Research has indicated that consuming between 1–6 grams of cinnamon as part of a meal can significantly reduce blood sugar levels in the crucial 2-hour post-meal period that follows. Add a pinch of cinnamon to your breakfast cereal, coffee, fruits or dessert for better glycemic control.
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The post-meal release of insulin is enhanced by the release of the intestinal hormone glucagon-like peptide 1 (GLP1). Research has demonstrated a relation between sleep deprivation and the peak release of GLP1, which may elevate the quantum and duration of a blood glucose spike. Acute insulin-residence has also been shown to be a result of sleep deprivation.
Improving the quality and quantity of your sleep can thus have a significant beneficial impact on your blood sugar levels. An analysis of data from various studies that assessed the relationship between sleep and the risk of diabetes shows a U-shaped relationship, with both too much and too little sleep associated with an increased risk of diabetes. The optimal sleep duration according to this analysis was deemed between 7 and 8 hours.
The carbohydrates and sugars in the food we eat are broken down into simple sugars, glucose and fructose, which then enter our bloodstream, causing a rise in our blood sugar levels. The body releases a hormone called insulin to counter this rise, often called a ‘spike’. However, frequent, prolonged or very high spikes indicate that the body is failing to extract glucose from the bloodstream, or has developed insulin resistance.
Measuring postprandial blood sugar (meaning blood sugar levels after 2 hours of eating) is a way to learn more about how insulin and glucose are interacting with one another within the body. This is a critically important health metric for both non-diabetics and diabetics since it provides better insights into the state of one’s metabolic health.
Keeping postprandial blood sugar in check is essential for anybody looking to maintain good health and fitness. Simple modifications to your exercise routine (when you exercise), meal plans (when, what and how much you eat and adding certain foods to your diet) and sleep pattern (how much you sleep) can have a tremendous bearing on your glycemic control.
Disclaimer:The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new healthcare regimen including making any dietary or lifestyle changes.