DISCUSSION: Normal Postprandial Blood Glucose Levels

Without a doubt, maintaining normal postprandial blood glucose levels is critical to your health.

It helps you avoid diabetic complications such as heart disease, retinopathy, neuropathy and other health problems.

Postprandial refers to glucose measurements that are taken after your meal. So ‘post meal,’ ‘after meal,’ and ‘postprandial’ all refer to the same thing.

Keep reading to find answers to 15+ questions. And if you have your own, feel free to ask them below.

What is the maximum safe blood sugar level post-meal?

There are a few different standards depending on the recommending agency and a person’s particular condition.

The American Association of Clinical Endocrinologists have a conservative (tighter/more stringent) goal of 140 (7.8) as the max “safe” level 1-2 hours post meal. Whereas the American Diabetes Association has a more liberal goal of 180 (10).

Obviously 140 (7.8) or lower is best because that is within the normal optimal range.

But some people are “allowed” a little more wiggle room – often those who are older, on a more difficult to manage insulin regimen, or have ‘brittle’ diabetes. These people may need looser goals to prevent hypoglycemia.

Is a postprandial blood glucose average of 120 (6.6) good?

Yes, if that’s your average you are within a healthy normal range.

As we just covered above, a postprandial blood glucose of 140 (7.8) or lower is best because that is within the normal optimal range.

What is postprandial hyperglycemia?

This simply refers to your after meal measurements being higher than normal.

• Postprandial = after meal or post meal blood sugar measurements
• Hyperglycemia = high blood sugar

Would love to know if the time it takes to metabolize a sugar source makes a difference on my blood readings. E.g., two tangerines v.s. two tangerine’s worth of juice. Which will give me the highest reading?

There probably wouldn’t be much of an overall difference as the sugar content would be the same – two tangerines worth.

The fiber content would be higher in the whole fruit, but without protein and fat to slow it down, they will probably have a similar spike.

Your question is essentially what the glycemic index (GI) was developed to address. While it is an interesting factor to consider, there are too many variables to use it solo. Even within the GI, there is a lot of variability between individuals and when multiple foods are added, it changes.

We know that the most critical factor impacting glucose is the number of carbs and second most–the type of carbs.

Sugars and white refined starches are likely to spike, whereas high fiber sources such as vegetables, beans, etc, are much more stable.

You could always conduct a blood testing experiment on yourself and do a pre-reading and post-reading check and compare the difference in elevation.

Will going gluten free help my after meal numbers?

It depends on what you substitute your “gluten” intake with.

Gluten itself does not affect your blood sugar levels significantly, it’s simply a protein.

However, gluten is a protein found in grains–specifically wheat, rye, barley and possibly oats (some people who do not tolerate gluten are still sensitive to oats and most oats have been manufactured in a facility which also uses other grain sources and therefore contaminates the oats).

Each of the above-mentioned grains are high in overall carbohydrate content.

Gluten free grains (rice, buckwheat, amaranth, quinoa, millet, etc) and many gluten free substitutes are also high in overall carbohydrate content. 

For example, if your gluten free pasta is made of corn flour and your gluten free muffins are made with rice flour (not to mention added sugars) you are not decreasing your carb intake. Therefore, your blood sugar levels are unlikely to change.

So the answer is no – going gluten free won’t affect your after meal numbers.

However, if you swap out wheat or gluten free bread for lettuce wraps or gluten free pasta for zucchini noodles, of course this will help your numbers!

So the message is: your overall carb intake matters much more than gluten. Simply switching to a “gluten free diet” is unlikely to make any difference.

What is the relationship between carbs and sugar? I thought sugar was the thing that is bad, but we count carbs. I don’t understand? How is sugar and carbs related to my blood sugar?

This can be very confusing. But the basic idea is that the total carbohydrates is the number one thing that impacts blood sugar and A1c levels.

The thing to understand is that sugar is one type of carbohydrate. Many carbohydrates you consume, for example, whole grain bread, will later break down into sugar.

When people talk about sugars and carbohydrates, or even glucose, they are often referring to the same thing. All carbohydrates (sugar being one of them) become sugar/ glucose in the bloodstream.

That’s why the total amount of carbohydrates you eat is the main factor to monitor.

Of course, the type of carbs you eat is important too. Simple sugars and “added” sugars (white starches and sweets) provide very little satiety and spike blood sugar more quickly than other types of carbohydrates (such as non starchy vegetables).

Carbohydrates higher in fiber are more nutrient dense choices as well – they provide vitamins, minerals and beneficial compounds your body needs.

So while it is always best to keep your sugar content low, carbs is most important to monitor because all those carbs will eventually become sugar in the bloodstream.

What ratio to fruit and protein should I eat to reduce the huge effect on post-meal blood glucose?

There really is no “special” or “magical” ratio to follow. However, just keep in mind that if you do choose to eat some low carb fruit, make sure your “protein” food doesn’t contain a lot of carbs.

For example, eating fruit with flavored yogurt isn’t a good idea because flavored yogurt is notoriously high in sugar. Whereas eating your fruit with plain Greek yogurt, eggs, cheese, nuts, or cottage cheese will provide both protein and fat sources to balance out the fruit.

My post-meal levels seem to fluctuate a lot, how do I maintain a normal level of the sugar?

Firstly, remember there is some degree of variability in glucose throughout the day and this is normal in people with or without diabetes. There is also some variability in the meters themselves.

If by “fluctuate a lot,” you mean your numbers are 110, 116, 122, 97, 118, etc, that is normal and healthy – your levels are still being maintained within a ‘normal’ range.

However, if they are fluctuating out of range like 65, 147, 248, 83, 300, then you have a different issue going on.

First, make sure the lifestyle factors you can control, are in check and consistent.

For example:

• Watch your daily carb count – remember, the total amount of carbs you eat has the greatest impact on your blood sugar levels.
  
• Eat a consistent amount of overall carbs at your meals
• Have consistent mealtimes
• Get adequate amounts of sleep, which means going to bed and waking up at reasonable times.
• Exercise regularly
• Manage stress

Once you get all of those things in check, if you still have blood glucose levels that are all over the place, it is time to schedule an appointment with your doctor and/or educator to discuss medication management and get more personalized help.

Some days when I check my blood sugar after a meal, it is lower than fasting – fasting 94 (5.2) and after meal 89 (4.9), why is that?

Firstly, it is not uncommon for people with type 2 diabetes to have fasting sugar higher than postprandial. Having a higher fasting glucose does sound strange because you haven’t eaten or done anything, right?

But even when you don’t eat the liver can still produce glucose, so for some people, this may be a case of what’s known as the dawn phenomenon.

However, because both of your pre and post meal numbers are in range (not too high and not too low), this is exactly what you are aiming for! Remember there is always fluctuation and variability in glucose. So I would not worry about it unless you are dropping into hypoglycemic (low blood sugar) range, or your levels are higher than they should be.

Another thing to question in this case is how long did you wait after the meal? If it is less than an hour or longer than 2 hours, your reading isn’t reflective of the meal. It may also be because your medication is working well.

There are usually a number of factors to consider. But overall, if your levels are within the normal healthy range, you don’t need to be concerned.

How long after a meal do I test?

Between 1 and 2 hours from the first bite of food.

It does help to have a watch or alarm you can set to notify you.

Why does blood glucose change all the time?

Everything in your body is changing all the time. There is fluctuation in your temperature, your blood pressure, your pH, blood sugar, etc. This is the essence of metabolism.

Like a machine that starts off with raw materials and converts them to usable energy, our bodies process nutrients, burn food for fuel, use that fuel, send signals to require more nutrients, and so on.

Think of it like this: The work of the heater or air conditioner is to maintain a comfortable temperature. So in the same way room temperature can vary a bit and is always changing in small degrees, the body is constantly trying to maintain general equilibrium.

Your blood glucose is not supposed to stay exactly the same. But it is supposed to stay within a healthy ‘normal’ blood sugar range.

Should I be testing after every meal?

That is between you and your doctor. It depends on your levels, your control, your goals, and the usefulness of the information.

Remember that the purpose of testing is to provide you and your team with data to make informed decisions. If testing after all meals is helpful to this end, by all means, do it!

Testing regularly can certainly help you understand your body faster and monitor your goals more closely.

Sometimes if you are in much better control and getting consistent numbers over time, it’s ok to back off a bit and give your fingers (and wallet) a bit of a break.

Why does my sugar spike after meals?

Because food raises blood sugar.

Primarily the nutrient that causes “spikes” is carbohydrates. But all food has the effect of converting to energy, to some degree.

It is expected that glucose levels will elevate after meals, especially when they contain carbs. That’s why it’s recommended that you count your daily carbohydrate intake so you know what you’re consuming – don’t leave it to chance!

But, if there is a >40 mg/dL (2.2 mmol/l) increase from beginning to end of a meal, that indicates a meal that is too high in carbohydrates.

If you are seeing this pattern, take note of what you’re eating and how many carbs you ate and work on decreasing those carbs. Or, if your carbs are already really low, work with a medical professional. It may be that you need to introduce medications or manage them differently.

How come the food I eat one day brings my blood sugar down and the very next day my blood sugar reading is higher?  

It’s hard to say without knowing more details. What is the food? Was it a source of carbohydrates? And was it eaten alone or in combination with other things?

For example, if the salad you ate the first day with chicken “brought it down” but it went up the next day when you ate a plate of pasta, it’s probably the additional carbs or the combination of foods.

Also, remember there are other variables besides food that can impact blood sugar–stress, sleep, exercise, hormonal changes, etc. It may not be the food itself, but the variable. Was the food eaten in different context? Did your salad have no dressing one day, but a sweet western with croutons the next?

Keep in mind that there are always several variables to consider. Be sure when doing your blood test in pairs to test before the meal, then 1-2 hours after the meal.

Finally, remember that meters aren’t 100% accurate. So if you’re talking about 10 or 15 points (mg/dL), it may be that there wasn’t really as much difference as you may think.

So what is the 2 hour postprandial glucose goal?

The optimal goal is less than 140 (7.8) or lower because that is within the normal healthy range.

However, in some cases your physician may set a higher goal of 180 (10).

Hopefully all this info resolves any questions you may have about normal postprandial glucose levels. However, if you still have questions, please ask them below and I’ll do my best to answer them.

Please pin, tweet or share this info to help others. Thanks!