Blood Sugar Testing 101 for People with Type 2 Diabetes…The Why, When, What’s Normal, and What to Do With It?


I am a registered dietitian, certified diabetes educator, have run Diabetes Centers in hospitals, have a private practice in medical nutrition therapy specializing in metabolic syndrome, weight loss, and type 2 diabetes and have written a NY Times Bestselling book on diet and lifestyle for metabolic syndrome, pre diabetes, and type 2 diabetes. January 10, 2012,  was the world-wide release of my newest book, The Diabetes Miracle.  I have had type 2 diabetes for 15 years.  Guess what?  If you asked me what my blood sugar is right now, I have no idea.  Neither do you!

●Did you know that unless your blood sugar is over 200mg/dL, you most likely will have none of the traditional diabetes symptoms such as excessive thirst, urination, fatigue, hunger, or wounds that will not heal?

 ● If you’ve run blood sugar over 200mg/dL for a period of time, you probably won’t even have symptoms when your sugar exceeds that 200mg/dL point.

 ● If you have been prescribed medication for diabetes that is aimed at reducing your blood sugar and you begin to feel shaky, dizzy, nauseated, can’t speak clearly, can’t think, feel wiped out….you may assume that you are hypoglycemic.   Are you?  Without testing, you really have no idea…your once high readings may have returned to normal range…and your body may assume you are hypoglycemic when you are far from it!   If you grab some juice or glucose tabs, you will push that normal sugar right back into the very high range. 

● Or maybe those symptoms really are hypoglycemia and if you don’t treat it, you will lose consciousness, fall down the stairs, drop your child, run off the road.

● Your Hemoglobin A1C might be 6.3 and you think to yourself:  “Wow, my blood sugar is now normal…why should I spend the money and take the time to test?”  Do you realize that hemoglobin A1C is your average blood sugar 24 hours/day, for about 3 months back in time?  An average is the average of highs and lows.  It is possible to have a 6.3 hemoglobin A1C because you are averaging normal from blood sugar readings that are in the high 200’s and in the low 50’s! 

● You may be following your meal plan, exercising, are not stressed, haven’t been sick and think maybe you don’t need that medication.  Without monitoring, how can your physician make an educated decision on your medication or doses?



ImageTesting your blood sugar is a quick, not too painful, fairly accurate way to determine where your blood sugar stands at different times of the day.  Many people don’t know when they should test.   People with type 1 diabetes usually test before each meal, at bedtime, and anytime they feel low.  People with type 2 diabetes have a much different test schedule.

I can’t tell you the number of patients I’ve seen who only test first thing in the morning.  They initially come to my office with months of wake up (fasting) readings.  I scan them, see some high readings, and ask…What do you think caused your fasting reading to be so high on this morning or that one?

Invariably, the patient will “confess” one of the following scenarios:

– The night before, they went out to dinner late and ate pasta, garlic bread, and zeppoles. .

-The night before, they over-snacked watching a late night football game. 

-They had a bagel for breakfast and a candy bar in the afternoon the day before.

-They had a snack right before bed

Well, here is an eye-opener.  When a person with type 2 diabetes has a high fasting blood sugar, it is not because of anything that happened dietarily the day or night before!!!!  Why?  Carbohydrate is the nutrient that converts into blood sugar and carbs have a lifespan of about 5 hours.  When more than 5 hours pass after you eat carbs, your brain sends a signal to the pancreas to release a hormone called glucagon and this hormone signals the liver to release glycogen (sugar stores) into the blood.  So…anytime you check your blood sugar and more than 5 hours has passed since you last ate, you are looking at your liver’s self feeding mechanism!

If you only test your blood sugar in the morning before you eat, you are only seeing what your liver is up to.  That reading tells you nothing about how your body is reacting to the food you ate the previous day/night.

So, how can you find out how you are handling food (specifically carbohydrates)?  You should consider testing your blood sugar 2 hours after the START of a meal.  So, if you are having dinner at 6 PM and want to assess how high your blood sugar rose from dinner, test at close to 8PM.  If you wait until bedtime at 11PM, you missed it….because you are at the 5 hour mark.  After you eat, your sugar rises for about 2 hours, then comes back to normal over the next 2 hours, then hangs tight for the last hour of the 5 hour blood sugar curve.

If I have type 2 diabetes, and I want to know how my sugar is doing at the 2 times of the day it is likely to be highest…I would check first thing in the morning before I eat (checks the liver) and 2 hours after the start of my largest meal (checks the food). 




                                                          WHAT’S NORMAL?

I suggest that you ask your MD or health care provider for what your target blood sugar should be.  The following are the blood sugar ranges I typically use with my patients with type 2 diabetes whether they are following diet/exercise or diet/exercise/oral meds:

Fasting:  blood sugar less than 120mg/dL  (80-120mg/dL)

2 hours after the start of a meal:  blood sugar less than 140mg/dL.  If you happen to miss the 2 hour after time and check at 3 hours it should be under 130mg/dL.  If you don’t check until 4 -5 hours after the start of a meal it should be under 120mg/dL.  You can see that the highpoint is at the 2 hour mark.

Those with type 2 diabetes taking insulin will usually test premeal and at bedtime.  Your MD will tell you your individual targets if you use insulin to control your diabetes.



I find it is helpful to write my numbers down.  I know that the meter can keep hundreds of readings in memory…and I know they are time stamped (if you bother to set the meter’s time) but for me….I like to see patterns.  Even if you only use a sheet of paper…you can head it like this and mark or circle your readings that are out of zone.  Then, try to come up with a reason.

Fasting        after breakfast                after lunch                     after dinner                   Reason

110                 2hrs= 126                             

107                                                 2 hrs = 157                                                  Had a bagel

140                                                                                       2 hrs = 122            Did not sleep well

152                 3 hrs = 120                                                                                  Poor sleep                                                                                                                                                                                                                                          

139                                                                                       2 hrs = 109             Poor sleep


By highlighting any numbers that are out of range and trying to come up with a reason for the reading, I can see that my sleep difficulties are really affecting my blood sugar and may need to address this with my MD if the situation does not improve.


 Why would my fasting reading be elevated?

  1. Poor sleep
  2. Pain
  3. Infection or Illness
  4. Not eating a night snack (liver is “on” longer)
  5. No exercise previous evening (muscles “consume” blood sugar for hours after exercise ends)
  6. Forgot to take my Metformin at bedtime
  7. Right before menstrual period
  8. Stress out

Why would my post meal readings be elevated?

  1. Forgot my medication today
  2. Pain
  3. Illness or infection
  4. Overeating carbs at the meal I’m checking
  5. No exercise earlier in the day
  6. Right before menstrual period
  7. Taking steroid based medication (prednisone/cortisone)
  8. High stress day


What about low blood sugar?

Blood sugar under 70mg/dL, when taking diabetes medication (orals or insulin) is considered to be hypoglycemia and needs to be treated as directed by your physician.  The standard treatment is a quick source of carb like 3-4 glucose tabs, ½ cup juice, ½ can regular soda (6 ounces), 8 ounces nonfat milk,, etc.  After waiting 10 minutes, retest your blood sugar and make sure it is over 80.  If it remains under 80 after the treatment, repeat and retest in 15 minutes ascertaining that does, indeed, rise over 80.  Report repeated hypoglycemia (not an isolated event) to your physician as you may require a medication or dosage change.

Diane Kress is the author of the New York Times Bestseller; The Metabolism Miracle and it’s companion book, The Metabolism Miracle Cookbook.  She just released her breakthrough book on preventing and controlling type 2 diabetes: The Diabetes Miracle.  Read more about her program at


About Diane Kress

Author of The New York Times Bestseller; The Metabolism Miracle, The Metabolism Miracle Cookbook, and The Diabetes Miracle. and The Metabolism Miracle, Revised Edition. Owner, developer, and administrator of The Metabolism Miracle's support site: Registered Dietitian, Certified Diabetes Educator, Email:
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3 Responses to Blood Sugar Testing 101 for People with Type 2 Diabetes…The Why, When, What’s Normal, and What to Do With It?

  1. Thank you for that explanation. Knowing the causes other than eating and the right timing is helpful.

  2. marnie davis says:

    So…if I go to sleep with 112 and wake up with 157…it’s my liver over responding? Why doesn’t our liver do this thru the day if I don’t eat enough rather than having a sugar low?
    It happens whenever you go more than 5 hours without eating. At night, your blood sugar dips, the liver responds, and you wake up high. During the day, if you go more than 5 hours without eating you can feel the low and the liver will respond and bring your blood sugar back up. But, if you are taking one of the many diabetes medications that work for 12 hours to lower blood sugar…it’s the medication that drops you lower than normal.

  3. Elton says:

    As the admin of this web site is working, no doubt very soon it will be
    famous, due to its quality contents.

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