Aa
Aa
A
A
A
Close
Avatar universal

Question about Blood Glucose Levels

I have read the fasting and post-meal (+2 hours) glucose levels for individuals with and without diabetes.

Some "reputable" diabetes sites recommend that "normal" blood glucose levels are under 180 two hours after a meal, while other sites recommend under 140, suggesting that 180 is too high even after two hours. I've even read various doctors give different recommendations that are between 120 and 180 two hours after a meal.

I have read on some sites that the 2-hour post-meal measurement begins when you begin the meal, which makes little sense to me. I realize that your body will work during the meal to reduce blood glucose, but until the meal is actually finishing, you're still ingesting more food which may allow your body to retain an elevated blood glucose level. So it makes more sense to me to measure the blood glucose level two hours after the meal has finished, especially when some meals consist of multiple courses, and the entire meal can last up to an hour. Your thoughts on this?

Also, I am interested in knowing what a "normal" blood glucose level is directly after a meal, if it is supposed to lower to under 180 (or 140 according to other sites) within two hours after the completion of a meal.

I am assuming (perhaps wrongly) that even if you are non-diabetic, that foods you eat (which may or may not be healthy) can raise your blood sugar to such an elevated level that you will simply have too much sugar in your system for even a normally healthy personal whose body produces and handles insulin normally and whose organs are normal to lower that amount of sugar below 180 even two hours after a meal.

So I am assuming (again, perhaps wrongly) that being able to have your blood glucose level under 180 (or 140) two hours after a meal, even if you are non-diabetic largely depends on simply what you eat and the quantity.

So depending on your diet, can you actually be falsely diagnosed with diabetes based on high blood glucose readings simply because of your diet?

Can anyone offer any insight or counterpoints to consider regarding the points I have addressed? I am really trying to better understand blood glucose levels as they relate to a prognosis of diabetes, especially in relation to your diet and quantity of food.
7 Responses
Sort by: Helpful Oldest Newest
141598 tn?1355671763
You're welcome medicaladvice. Glad to be of assistance. Good luck and post back if you find evidence on postprandial ranges and vs food consumption. I'll continue searching too.
Helpful - 0
Avatar universal
"But it would not be immediate. Doctors provide careful warnings about glucose spikes, at least mine have, can lead to disruption of the heart rhythm."

Understood. I should have worded that better. I meant that once the caloric intake is reduced and the body adjusts, that over a short period of time, the blood glucose levels would probably drop to within normal levels, assuming the individual is otherwise healthy and has normally functioning organs.

"Have you spoken with an Endocrinologist and a Nutritionist who are specialist in Sports Medicine? They may have personal studies/research on your subject matter, more than I can offer."

I may have to do that, but I appreciate the advice you've given as it definitely brought up some good points and things to consider.

One of the main things I was pondering through all this was that if 140 - 180 is the common blood glucose range that doctors look for 2+ hours post-meal, what do they estimate is/should be a common range for blood glucose very shortly after a meal if someone is eating recommended healthy foods in controlled portions? I know it varies from person to person depending on actual diet and other factors, but just a general range to indicate how many blood glucose points a doctor expects to be reduced every hour after a meal. This is what I simply can't find anywhere.

And that's what made me wonder if people in some situations could be diagnosed with diabetes because their diet was simply giving them too high of a blood glucose reading for it to be adequately reduced to below 180 in 2 hours, and not necessarily because their body could not process the insulin or their pancreas was malfunctioning, but rather that even working normally, it was just too large of a task for the pancreas to reduce that amount of glucose in 2 hours.

I also understand that if the A1C or even the liquid glucose solution tests were used that an actual diabetic diagnosis would be much more reliable.

But regardless, I understand that no matter the cause, having sustained levels of high blood glucose simply isn't healthy, and should be reduced no matter what.

WaveRider, I appreciate the knowledge and expertise you have provided. Thanks much.
Helpful - 0
141598 tn?1355671763
Points well taken.
"I am wondering if that type of food intake could result in a sustained high blood glucose level even if the person is not diabetic because their body simply can't reduce the blood glucose fast enough based on the amount of food intake,"

Yes, good point. One cannot expect the human body to compensate nor regulate to normalcy for over indulgence.
This is how one becomes diabetic. Over time the body can only do so much to regulate and disperse excessive glucose, then its up to the human.

"..but if the person was to simply cut their food intake, the blood glucose would almost immediately drop to within medically acceptable levels of normalcy."

Losing weight through diet and proper nutrition, reduction in meal portion size, using common sense comes to mind. But it would not be immediate. Doctors provide careful warnings about glucose spikes, at least mine have, can lead to disruption of the heart rhythm.

Have you spoken with an Endocrinologist and a Nutritionist who are specialist in Sports Medicine? They may have personal studies/research on your subject matter, more than I can offer.
Helpful - 0
Avatar universal
"To answer your 1st question, yes, if the A1c says your percentile falls into the diabetes range, you would be considered a diabetic. On the other hand if you ate like a pig, cow and a horse all combined into one yet the A1c results said normal or below normal levels, then the body is handling and dispersing the excess glucose accordingly. In this latter case, I don't believe one would be called a diabetic just fat. "

Referencing the above....even if you're non-diabetic, and all your organs (especially pancreas & kidneys work fine), your body handles insulin normally, and any test administered by a doctor would normally indicate you're non-diabetic.....isn't there just a point where depending on what/how much you eat, your normally-functioning body just simply could not decrease your blood glucose levels to below 180 after several hours?

Not necessarily thinking of someone that's obese from excessive food intake....but rather possibly a weight lifter/athlete that takes in 3000 - 5000 calories per day.....most healthy food and probably mostly protein-heavy anyway in addition to protein and muscle-mass gain supplements. For someone with a sedentary lifestyle, that diet would make them obese in short order. But for the weight lifter/athlete, he's using that amount of food for fuel that gets burned fairly fast.

I know the exercise and the healthy diet (even if the calorie intake is high) helps reduce blood glucose and regulate other body functions, but I am wondering if that type of food intake could result in a sustained high blood glucose level even if the person is not diabetic because their body simply can't reduce the blood glucose fast enough based on the amount of food intake, but if the person was to simply cut their food intake, the blood glucose would almost immediately drop to within medically acceptable levels of normalcy. By "sustained" I mean that the person would have higher than normal blood glucose on a regular basis.
Helpful - 0
141598 tn?1355671763
You're welcome. To answer your 1st question, yes, if the A1c says your percentile falls into the diabetes range, you would be considered a diabetic. On the other hand if you ate like a pig, cow and a horse all combined into one yet the A1c results said normal or below normal levels, then the body is handling and dispersing the excess glucose accordingly. In this latter case, I don't believe one would be called a diabetic just fat.

One cannot have sustained elevated glucose levels without being called a diabetic. But then you have to define your meaning of "sustained". If over 24 hours then diabetes comes to play. If an hour or two, or even three then my answer is no, I don't feel diabetes should be a concern. With proper nutrition, weight control and moderate exercise one can reduce their glucose to normal levels, without the aide of medication. You would then become a non-diabetic, a person not afflicted with the diabetes disease. This has been proven countless number of times.

“Given an "average" healthy non-diabetic individual, how many blood glucose points will their body reduce in an hour until they reach their "normal" level?”
This question is too general. One cannot define average healthy but can generalize what average healthy is, which is found in all Google searches and med books. As clinical trials and research programs are not conducted with a specific exact group of humans – same ethnic background, same gender, exact age, exact height, & weight - and all eating the same foods, the same amount, at the same of day and all doing the same physical exercise at the same time and duration all under close watchful supervision for months on end, how are they matched to you, or to me, or to John Doe? Even if they did, you would have find that one trial/study/research that matches your exact human qualities and lifestyle. Then you would have YOUR average healthy range, and I to me, and so on.

Don't feel bad if Google cannot find your answers. I'm an ex-computer scientist and worked on ARPNET in the early 1980's before it was turned over to the public and rebadged The Internet. Computers have been in my life for over 40 years. I have done my searching and have asked a number of doctors and surgeons of such trials/studies/research and all have shaken their head no. That's why they call medicine a science, nothing is absolute.

I cannot speak on the 20 - 40 range for again you're speaking ranges that may not apply to me, my neighbor or my wife. To you maybe, and a few others, but one cannot generalize ranges. I know my nutrition values and what they do to my glucose levels. I know what individual foods that cause a rise and what combination's of foods that do the same. Research has shown the 180 mg/dl postprandial as the max range. This is what I try to obtain daily. I try to eat at the same time each day so body knows when its being supplied food and when it needs to burn energy (glucose). Fudging an hour doesn't hurt, but two to three hours and my levels gets a little whacky, sometimes 25  ±10 points above and others 25  ± 10 points below with the same food no less. Go figure. What is important is for you to understand your foods, what they do to your body, and when they do something to your body. Then you can determine YOUR approximate glucose rise and fall levels.

I hope this makes sense.


Helpful - 0
Avatar universal
Thanks for the info and timely response.

I understand about the time range for the A1C test, and why it's perceived to be a more reliable test for diabetes, but again, if a healthy person simply consumes too much food for their body to reduce the blood glucose levels to "acceptable" levels, wouldn't they still be considered diabetic even if they technically weren't, and their body produced and handled insulin normally, assuming that the A1C demonstrated elevated levels considered to be in a diabetic range?

I understand that those elevated levels aren't healthy regardless, and should be reduced, but I would think it is very possible in some situations to simply have sustained elevated levels, while at the same time not be diabetic....and that if the eating behavior was corrected, that their A1C/blood glucose levels would naturally decrease to within normal levels without the aid of any medication, assuming the individual is healthy and actually has no other complications attributable to diabetes.

I have one more question I have been unable to find a clear answer to through Google searches. Given an "average" healthy non-diabetic individual, how many blood glucose points will their body reduce in an hour until they reach their "normal" level?

Based on research and blood glucose tests conducted before, directly after and 2+, 3+ and 4+ hours after meals, I'm under the impression that roughly somewhere around 20 - 40 blood glucose points are reduced per hour until the individual reaches their "normal" range. Should that 20 - 40 range estimation actually be smaller, or does that sound about right?

Again, thanks for the info and timely response.
Helpful - 0
141598 tn?1355671763
Here's my take. Don't get caught up in ranges. Go by what your doctor says and what your lab states is YOUR range.

A safe normal postprandial (2-4 hours) has been considered <180 mg/dl. Eating the proper foods, the obtainable goal has been <140 mg/dl. These are goals for diabetics and non-diabetics. However, these goals may not be correct for medicinal induced diabetics; one that has diabetes as a side effect of medication. Their "normal" range may exceed these ranges by their doctor/hospital. Also, senior age may alter the range (raise) for that patient. Healthy 92 yo aunt has a normal range of <160 mg/dl, fasting.

Quantity along with quality of foods both play a large role with glucose levels - type of foods one consumes, how much oe consumes in one sitting/standing, body weight, and of course physical exercise one may or may not undertake. This may be the reason for the large differences in ranges? 120 mg/dl two hours after a meal seems awfully low even for a non-diabetic. But was this meal a lettuce salad, no dressing only salt and pepper to obtain 120 mg/dl? Heck, if I had a fasting glucose level of 80 mg/dl, ate the above salad, and test 2 hours after, I surely would be below the 120 mg/dl level. Ain't so if I had a corn beef sandwich on rye w/mustard, tater salad, salad, fries w/ketchup and a coke. But I think I would test <180 mg/dl with this "meal". What I mean is no where will you read the defined term of "meal" in relation to glucose ranges. One type of food may be OK for someone but not the other. Take fruits for example; I can only consume berries. Everything else jacks my glucose levels skrockety high. This is what I mean by don't get caught up in ranges.

When to test postprandial? Depends on what has been consumed. Certain foods take longer to be digested so glucose is slower to get into the blood stream. If one watches carefully what they eat they will know when to test. Is 2 hours, 3 hours or is 4 hours the max peak of blood sugar?

"So depending on your diet, can you actually be falsely diagnosed with diabetes based on high blood glucose readings simply because of your diet?"
Yes, but mostly untrue. Food doesn't come into play when you fast 8-10 hours prior to testing. And, this is where the A1c test comes in to play. One takes the A1c test at given time, fasting or not fasting. The A1c will measure back three months the amount of glucose in your blood stream, the results are shown in percentile. Can't cheat on this test.

Hope this answers your thoughts.
Helpful - 0
Have an Answer?

You are reading content posted in the Diabetes - Type 2 Community

Top Diabetes Answerers
231441 tn?1333892766
Manila, Philippines
Learn About Top Answerers
Didn't find the answer you were looking for?
Ask a question
Popular Resources
Here are three summertime recipes that will satisfy your hunger without wreaking havoc on your blood sugar.
If you have prediabetes, type 2 diabetes isn’t inevitable. Find out how you can stop diabetes before it starts.
Diabetes-friendly recipes and tips for your game day party.
Are there grounds to recommend coffee consumption? Recent studies perk interest.
Simple ways to keep your blood sugar in check.
8 blood sugar-safe eats.