If you have not been diagnosed with diabetes, but suspect you might have something wrong with your blood sugar, there is a simple way to find out if your blood sugar is rising to dangerous levels after you eat. Your doctor can test your blood sugar after you've eaten using a meter in their office, or you can borrow or buy a cheap drugstore meter and test your post-meal blood sugar yourself.

You do not need a prescription to buy the meter or strips. Even better, if you do this testing at home, you do not run the risk of having a "diabetes" diagnosis written into your medical records which might make it impossible for you to buy health or life insurance.

To run a post-meal blood sugar test do following:

1. Borrow a family member's meter or buy an inexpensive meter and strips at the drug store or Wal-Mart. The Wal-mart Relion meter and strips or the meters sold under drugstore names by TrueTrack (CVS, Walgreens, etc) are usually the least expensive. Many meters come with 10 free strips. If you need more, buy the 50 strip boxes. Look for specials at the drug store where you get the meter and strips for the price of the strips. Strips do not keep for very long, so don't buy more than you need for a couple tests.

2. Familiarize yourself with the instructions that came with your meter so that you know how to run a blood test. Practice a few times before you run your official test. Each meter is different. Be sure you understand how yours works.

3. The first thing in the morning after you wake up but before you have eaten anything, test your blood sugar. Write down the result. This is your "fasting blood sugar."

4. Now eat something containing at 60 - 70 grams of fast acting carbohydrate. A bagel makes a good test food. If you can't eat wheat, a large (8 oz) boiled potato of a cup of cooked white rice will do. Avoid fats as they will slow down the action of the carbohydrate.

5. One hour after you started eating, test your blood sugar with the meter. Write down the result. If you lose track of the time measure as soon as possible. The numbers will still be useful.

6. Two hours after you started eating test your blood sugar again. Write down the result.

7. Three hours after you started eating, test your blood sugar. Write down the result. You are now done and can eat whatever you want.
   

What Your Meal Test Numbers Mean

Take Into Account The Effects of Low Carbing

If you are currently low carbing, your test result will be slightly higher than it would be if you were eating over 150 grams of carbs a day. If you were going in for an official post-meal test, ordered by your doctor, you would be told that you have to eat 150 grams of carbohydrate during 3 days before your test to get a valid result. However, since this is an informal test, and since if you have been successful low carbing you probably don't want to stop your diet for that long, you can make an informal adjustment to your post-meal test results that will account for the fact that low carbing temporarily raises your post-meal values when you eat an unaccustomed large dose of carbohydrate.

To make this correction, just subtract 10 mg/dl from any post-meal result that is over 140 mg/dl at 2 hours if you are currently low carbing. This is a rough estimate, but close enough for this kind of home testing.

Understand Your Meter's Margin of Error

Your meter is not as accurate as a lab-drawn test would be. Figure in a 10% error, plus or minus. So if you got a 100, your results might actually be 90 to 110 if you were tested at a lab. The documentation with your meter might tell you that it is only accurate to within 20%, however, in practice most meters nowadays are more accurate than this.

NOTE: All blood sugar levels discussed on these pages refer to plasma calibrated meter readings. Users of blood calibrated meters, including most people in the UK, should divide the numbers given here by 1.12 to get the blood calibrated equivalents.

Interpret your result

Normal Blood Sugar

If your blood sugar remained under 100 mg/dl (5.6 mmol/L) whole time, you have completely normal blood sugar and can stop worrying about it.

If your blood sugar did not reach 140 mg/dl (7.8 mmol/L) an hour after taking a large dose of carbohydrates and if it was below 120 mg/dl (6.7 mmol/L) two hours after you ate the large dose of carbohydrate, most health authorities would also say that you are normal. These numbers, 140 mg/dl at 1 hour and 120 mg/dl at two hours after a meal are what Joslin Diabetes Clinic of Harvard Medical School defines as upward limit of "normal."

However, this "Normal" number is probably contaminated because a lot of "normal" people used in medical studies are people who, though they have normal fasting plasma glucose numbers, may actually be in the very early stages of the process that leads to type 2 diabetes. Some very recently published research has found that there is already evidence of impaired beta cell function when test results are over 100 mg/dl 2-hours post consumption of a 75 gram dose of glucose. The beta cells are the cells that secrete insulin that keeps you from becoming diabetic.

If your blood sugar returns to a level below 120 mg/dl at two hours and does not go over 140 mg/dl, your doctor will consider you normal, but it might be a good idea to cut back on the amount of carbohydrate you eat so as to retain the beta cell capacity you have now.

Impaired Glucose Tolerance

If your blood sugar surged over 140 mg/dl at one hour or stayed above 120 mg/dl at two hours, you may have what doctors will call "impaired glucose tolerance" or IGT. Another name for this condition is "pre-diabetes." Note that the values given here are lower than the values doctors used to diagnose impaired glucose tolerance using a lab glucose tolerance test. That is because blood sugar does not rise as high after you eat a food that needs to be digested as it does when you drink pure glucose so you will not see as high a number with a food test as you will on a glucose tolerance test.

If you suspect that you have impaired glucose tolerance, don't ignore it. The excess glucose molecules that make up those elevated post-meal blood sugars will merrily bond to your body proteins, deposit themselves in your arteries, damage your kidney filtration units, clog up your retinal capillaries, and cause your nerve function to deteriorate leading to, among other things, impotence and pain. Keep this up, and in another five or ten years you'll be one of those people with "newly diagnosed" diabetes who have serious, established, possibly irreversible long-term complications.

But on a more cheerful note, if you catch your blood sugar abnormality at this point, there is a very good chance that by managing your blood sugar through dietary control (i.e. cutting carbohydrates) and exercise, you may never see it deteriorate. Indeed, you may avoid developing any complications at all.

If you suspect you have impaired glucose tolerance, be sure to discuss this finding with your doctor. If he or she tells you it is "nothing to worry about" it's time to find another doctor-- one who is more up-to-date and who will help you manage your blood sugar so you can avoid heart disease and development of other diabetic complications.

Studies have shown that people with impaired glucose tolerance who lose weight and start exercising can reverse their blood sugar deterioration and prevent themselves from progressing to full-fledged diabetes. There are also drugs that can help you, too. And the very best treatment is lowering your carbohydrate intake.

But if you wait for a diabetes diagnosis before taking action, it is too late. By the time your fasting blood sugar has reached 126 mg/dl (7.0 mmol/L) (the level at which your doctor will diagnose you) at least half of your beta cells will have already died and they won't regenerate.

Diabetes

If your blood sugar went over 200 mg/dl (11.1 mmol/L) in either time period, you just registered a diabetic blood sugar level and should consult with a doctor as soon as possible. Two random tests results of 200 mg/dl are considered diagnostic of diabetes according to the highly conservative American Diabetes Association. Again, if your doctor says, "Let's just check it again in a couple months" and does not urge you to take a more aggressive approach, it's time to look for a new doctor, one who has kept up with the current approaches to managing diabetes. It's your kidneys, heart, nerves, and vision that are at risk, not his.

Low Blood Sugar

If your blood sugar goes up at one hour and then drops below 70 mg/dl (3.9 mmol/L)at the two hour point you have what is called "reactive hypoglycemia." Your blood sugar went up but your body cranked out a huge dose of insulin to bring it back down--too much, in fact. That high dose of insulin resulted in your ending up with low blood sugar.

This, too, may be an early warning sign that you might be headed for diabetes, though it may take 20 years until it becomes apparent. Even if you don't progress to diabetes, reactive hypoglycemia may be a sign that you are insulin resistant and that your cell's resistance to insulin is forcing your body to secrete the very large insulin doses that are driving your blood sugar low. Insulin resistance, with or without diabetes may be a precursor to heart disease. Be sure to discuss this result with your doctor.

Ongoing Vigilance

Once you get a "baseline" post-meal blood sugar test and an Hba1c reading, if they are anything but rock solid normal, you should test your blood sugar response at home using same the test food you used for your first blood sugar test every three months or so to see how your blood sugar control is progressing. The values you get on a meal test may fluctuate by as much as 30 mg/dl (1.7 mmol/L) from what you saw on a previous meal test. But if you see your blood sugar registering test values that are steadily going up, test after test, it is time to talk to your doctor.

If you have abnormal post-meal tests, ask your doctor run Hba1c at least once a year and have him tell you the number you got on the test. Ignore whether or not your test meets the the lab definition of "diabetic" and track instead whether your test result is staying the same or rising. Aim for a value under 5.0%. Take serious action including, if necessary, the use of anti-diabetic drugs if your hba1c goes over 6.0%.

If you see anything that suggests deterioration in your blood sugar response,, take steps to bring your blood sugars down. For most people this will involve cutting their carbohydrates. Most people with mild blood sugar abnormalities can attain completely normal blood sugars through cutting out excess carbohydrates from their diets, especially fast-acting ones like those in soda, candy, cake, white flour, sugars and starchy foods like potatoes.

Use your meter to determine how much carbohydrate you can eat without causing a blood sugar spike. The closer your blood sugar stays to 85 mg/dl at all times, the better off you are. Remember that the lower your post-meal blood sugar, the lower your risk for heart attack and other diabetic complications.