- Fasting blood glucose
- Hemoglobin A1c
- Oral glucose tolerance test (OGTT)
Fasting blood glucose is the least sensitive screening for diabetes, yet it is used the most! It provides no indication of how food is influencing the blood sugar/insulin response. Also, it will be higher in those on a low carb diet (like Paleo) for at least a couple months.
- For example, red blood cells in people with diabetes turn over faster, which means they have less of a chance to bind to sugar and result in a falsely low A1c.
Fructosamine is not as popular, but you can ask your doctor for it. It represents blood sugar for the previous 2-3 weeks.
Oral Glucose Tolerance Test (OGTT), aka. post-meal blood sugar, provides information about how much glucose is circulating in the blood stream.
- The test at your doctor’s lab requires that you drink 75 grams of glucose on an empty stomach, then measures your blood glucose after 1 and 2 hours. Unfortunately, this test is very artificial- no one eats 75 grams of glucose! A 12-ounce can of pop only has 20g. Also, it’s very dangerous/uncomfortable for those with poor sugar control.
- An alternative to the standard OGTT is an at-home post-meal blood sugar test (see below for instructions).
- It’s cheap: all equipment can be acquired for <$20 online
- It’s convenient: can be done at home or work
- It’s personalized: helps you determine your own carbohydrate tolerance, as well as which foods work and don’t work for you.
- It’s safe: no dangerous/uncomfy blood sugar spikes from 75g of glucose.
- Check in with your nutritionist or doctor to go over the values. Everyone is different so the results must be interpreted based on your history, eating habits and general health.
You down with OGTT?*
Before You Start:
- Buy a glucometer and test strips.
- Most meters are fine, just make sure the replacement test strips aren’t too pricey.
- Print out the worksheet.
Day One of Test: Take 5 blood sugar readings according to this schedule:
- On the night before test day: fast for at least 12 hours.
- Take fasting blood sugar (reading #1) upon rising.
- Ok to sip water, not okay to eat or exercise.
- Eat your typical breakfast.
- Take blood sugar reading #2 just before lunch.
- Eat your typical lunch.
- Don’t eat or drink anything for 3 hours after lunch(not even a snack!) except for water.
- Take blood sugar reading #3 one hour after lunch.
- Take blood sugar reading #4 two hours after lunch.
- Take blood sugar reading #5 three hours after lunch.
- Eat your typical dinner.
- Stop eating 12 hours before the first blood sugar reading on Day Two.
Day Two of Test: Repeat Day One exactly
- Try to eat breakfast and lunch around the same time as Day One so that the blood sugar readings are also at about the same time. It’s okay if the times are not exactly the same.
- Stop eating 12 hours before the first blood sugar reading on Day Three.Day Three of Test: Same schedule as Days One & Two, but with a special lunch.
- Instead of your typical lunch, eat a fast-acting carbohydrate:
- Either a large (8-ounce) boiled potato, or 1 cup of cooked white rice.
- Do not eat any fat with the potato or rice.
- Take the same readings (one right before lunch and three after lunch at hours 1, 2 & 3).
- Please note: If you feel uncomfortable or dizzy during the 3 hours after lunch, suspend the test and eat something!
Goal of at-home post-meal blood sugar test
- 1 hour after lunch: <140 mg/dL an hour after a meal
- 2 hours after lunch: drops below 120 mg/dL
- 3 hours after lunch: returns to baseline (what it was before lunch)
What do you do if you have high blood sugar?
- The simple solution is a low-carb diet. Don’t go hog-wild and eat nothing but meat, because your diet needs to be balanced! Carbs are required for energy and to feed the trillions of bacteria living in your body. It’s ideal to completely eliminate refined foods (sugar, flour, vegetable oils), but if some sneaks in, it’s okay. Some people can get all the carbs they need from vegetables, but most of us need to toss in some roots and tubers. I like to suggest reframing carbs and aim to use them as a condiment.
- If your diet is already low-carb, there’s some more investigation to be had.