Glucose Tolerance Test—how to prepare??

[Anonymous]

My wife got a higher-than-desirable reading on her initial glucose screening test, so now she'll be taking the three-hour glucose tolerance test next week. She hasn't gotten clear instructions from her doctors on how to prepare for the test. First, the office sent her a document with a specific high-carb diet she was to eat for the three days before the test (two slices of white bread with every meal, potato with lunch and dinner, etc). Then they told her she can actually eat whatever she wants.

Does anyone have clearer advice or guidelines for how to get an accurate test reading? We've been eating a pretty low-carb diet generally, and I'm concerned that her body's not used to a lot of sugar and maybe struggles to process the glucose drink. So should she follow that document? And/or should she slowly ramp up her carb intake over the next few days, even before that three-day period? The test is next Thursday.

Thanks for any advice!!

[Anonymous]

I've never heard to eat a high carb diet. That's a bad idea just in general. She should eat as usual except don't eat before the test in the morning. If the test is later in the day she can eat something high-protein/high-fat (eggs or something) in the morning but I don't think you're supposed to eat anything for at least 3 hours before?

[Anonymous]

I exercised and ate low carb throughout my first pregnancy. Failed the glucose challenge at 28 weeks. Had to come in a couple days later for the 3 hour and only guidance I was given was to fast a certain amount of time beforehand, to bring something to do over the three hours, and just be aware that you can't really drink anything and it's twice the amount of sugar so you can feel pretty lousy by the end. Have a snack ready--something healthy!

I ended up just failing the 3 hour, so I officially had GD. I luckily did not have to make not much lifestyle change since we were already eating healthily and all I had to do was track my blood sugars 4x a day. They even let me go to 41 weeks.

Also, this is just anecdotal, but I will say that I'm pregnant again and have been monitoring my blood sugar from 12 weeks on and the days I eat more carbs in a row the more likely I am to have higher than average cumulative levels the following days versus if I have one carb as a treat. So I'm not sure I would suggest "ramping up carbs" to try and get an accurate reading, I think it may do the opposite and that the test is fairly accurate regardless.

[Anonymous]

Call the lab if she needs more info.

The point is to see how her body metabolizes sugar in a three house period. Some labs will take a baseline blood draw at arrival after a normal breakfast, some take a fasting baseline at arrival, some don’t take anything, with the understanding that the final number is what is key, as it will only be high if her body can’t metabolize the measured amount of sugar.

Some labs do provide a pre test diet, mostly because there is so much prevalence in low carb these days. If your wife is not normally pale or keto, there’s usually not a need to load with carbs to bring her body out of ketosis ahead of time.

I’m also going to say this: I know a lot of women try to game the system wrt this test. GD is no joke, and can have health implications to both the mother and baby at birth. It’s better to have accurate results than “good” results.

(Not saying this is the case, but the question comes up on here fairly frequently)

[Anonymous]

Anonymous wrote:Call the lab if she needs more info.

The point is to see how her body metabolizes sugar in a three house period. Some labs will take a baseline blood draw at arrival after a normal breakfast, some take a fasting baseline at arrival, some don’t take anything, with the understanding that the final number is what is key, as it will only be high if her body can’t metabolize the measured amount of sugar.

Some labs do provide a pre test diet, mostly because there is so much prevalence in low carb these days. If your wife is not normally pale or keto, there’s usually not a need to load with carbs to bring her body out of ketosis ahead of time.

I’m also going to say this: I know a lot of women try to game the system wrt this test. GD is no joke, and can have health implications to both the mother and baby at birth. It’s better to have accurate results than “good” results.

(Not saying this is the case, but the question comes up on here fairly frequently)

This is incorrect.

[Anonymous]

Anonymous wrote:I've never heard to eat a high carb diet. That's a bad idea just in general. She should eat as usual except don't eat before the test in the morning. If the test is later in the day she can eat something high-protein/high-fat (eggs or something) in the morning but I don't think you're supposed to eat anything for at least 3 hours before?

This is incorrect.

[Anonymous]

Anonymous wrote:I exercised and ate low carb throughout my first pregnancy. Failed the glucose challenge at 28 weeks. Had to come in a couple days later for the 3 hour and only guidance I was given was to fast a certain amount of time beforehand, to bring something to do over the three hours, and just be aware that you can't really drink anything and it's twice the amount of sugar so you can feel pretty lousy by the end. Have a snack ready--something healthy!

I ended up just failing the 3 hour, so I officially had GD. I luckily did not have to make not much lifestyle change since we were already eating healthily and all I had to do was track my blood sugars 4x a day. They even let me go to 41 weeks.

Also, this is just anecdotal, but I will say that I'm pregnant again and have been monitoring my blood sugar from 12 weeks on and the days I eat more carbs in a row the more likely I am to have higher than average cumulative levels the following days versus if I have one carb as a treat. So I'm not sure I would suggest "ramping up carbs" to try and get an accurate reading, I think it may do the opposite and that the test is fairly accurate regardless.

You’re missing the point. A normal body physiology would be able to manage any carbs that you do eat. The fact that your numbers are high is due to your GD, and inability to metabolize sugars, not due to the fact you ate carbs at all. A body working will will always bring itself back into balance.

[Anonymous]

Anonymous wrote:

Anonymous wrote:Call the lab if she needs more info.

The point is to see how her body metabolizes sugar in a three house period. Some labs will take a baseline blood draw at arrival after a normal breakfast, some take a fasting baseline at arrival, some don’t take anything, with the understanding that the final number is what is key, as it will only be high if her body can’t metabolize the measured amount of sugar.

Some labs do provide a pre test diet, mostly because there is so much prevalence in low carb these days. If your wife is not normally pale or keto, there’s usually not a need to load with carbs to bring her body out of ketosis ahead of time.

I’m also going to say this: I know a lot of women try to game the system wrt this test. GD is no joke, and can have health implications to both the mother and baby at birth. It’s better to have accurate results than “good” results.

(Not saying this is the case, but the question comes up on here fairly frequently)

This is incorrect.

What is incorrect about it? The general point of the test is to ensure that a body can metabolize a given amount of sugar in a certain amount of time.

And yes, different labs measure it differently, especially internationally. The final number is the key, but some practitioners will look at a differential.

[Anonymous]

Don’t carbo load. That will just sent her blood sugar sky rocketing. Eat a small protein rich breakfast a few hours before the test. If she has GD you want to get it diagnosed and manage it well, not cheat the test if she actually has it. This comes up all the time on here. There are also some crazy posters about GD who get really incensed when it comes up so I hope this thread doesn’t get derailed.

[Anonymous]

Anonymous wrote:

Anonymous wrote:I exercised and ate low carb throughout my first pregnancy. Failed the glucose challenge at 28 weeks. Had to come in a couple days later for the 3 hour and only guidance I was given was to fast a certain amount of time beforehand, to bring something to do over the three hours, and just be aware that you can't really drink anything and it's twice the amount of sugar so you can feel pretty lousy by the end. Have a snack ready--something healthy!

I ended up just failing the 3 hour, so I officially had GD. I luckily did not have to make not much lifestyle change since we were already eating healthily and all I had to do was track my blood sugars 4x a day. They even let me go to 41 weeks.

Also, this is just anecdotal, but I will say that I'm pregnant again and have been monitoring my blood sugar from 12 weeks on and the days I eat more carbs in a row the more likely I am to have higher than average cumulative levels the following days versus if I have one carb as a treat. So I'm not sure I would suggest "ramping up carbs" to try and get an accurate reading, I think it may do the opposite and that the test is fairly accurate regardless.

You’re missing the point. A normal body physiology would be able to manage any carbs that you do eat. The fact that your numbers are high is due to your GD, and inability to metabolize sugars, not due to the fact you ate carbs at all. A body working will will always bring itself back into balance.

I am not missing the point. I am pointing out that you can have GD even when you eat low carb and exercise and that it shouldn't change the result of the test. The fact that I can't process carbs is crystal clear to me given I am keenly aware of the carbs I eat and what it does to my body two hours later. I'm just trying to say, don't try to get an "accurate" reading by changing your diet or think anything you're doing healthy ahead of time messes with the test, I'm pretty confident the reading will be accurate if you follow the test instructions. And the good news is, if she does have it, it will likely not be a huge lifestyle adjustment like it is for some women when they get the diagnosis.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I exercised and ate low carb throughout my first pregnancy. Failed the glucose challenge at 28 weeks. Had to come in a couple days later for the 3 hour and only guidance I was given was to fast a certain amount of time beforehand, to bring something to do over the three hours, and just be aware that you can't really drink anything and it's twice the amount of sugar so you can feel pretty lousy by the end. Have a snack ready--something healthy!

I ended up just failing the 3 hour, so I officially had GD. I luckily did not have to make not much lifestyle change since we were already eating healthily and all I had to do was track my blood sugars 4x a day. They even let me go to 41 weeks.

Also, this is just anecdotal, but I will say that I'm pregnant again and have been monitoring my blood sugar from 12 weeks on and the days I eat more carbs in a row the more likely I am to have higher than average cumulative levels the following days versus if I have one carb as a treat. So I'm not sure I would suggest "ramping up carbs" to try and get an accurate reading, I think it may do the opposite and that the test is fairly accurate regardless.

You’re missing the point. A normal body physiology would be able to manage any carbs that you do eat. The fact that your numbers are high is due to your GD, and inability to metabolize sugars, not due to the fact you ate carbs at all. A body working will will always bring itself back into balance.

I am not missing the point. I am pointing out that you can have GD even when you eat low carb and exercise and that it shouldn't change the result of the test. The fact that I can't process carbs is crystal clear to me given I am keenly aware of the carbs I eat and what it does to my body two hours later. I'm just trying to say, don't try to get an "accurate" reading by changing your diet or think anything you're doing healthy ahead of time messes with the test, I'm pretty confident the reading will be accurate if you follow the test instructions. And the good news is, if she does have it, it will likely not be a huge lifestyle adjustment like it is for some women when they get the diagnosis.

Also, I've been seeing a lot of people to say eat beforehand. OP, be sure you get crystal clear instructions from the lab and/or doctor. This is, if my memory serves me, a FASTING test. The first blood draw is important because it helps get a sense of how well you've processed sugar overnight when having had nothing to eat. Then they will see how your body processes sugar after you drink at 1hr, 2hr, 3hr. I remember I was specifically told I could not eat anything many hours beforehand and they scheduled the test first thing in the morning to get it over with ASAP. To this day, they are most concerned with my fasting numbers I take every morning before breakfast versus the occasional high reading after a meal.

[Anonymous]

Anonymous wrote:

Anonymous wrote:I've never heard to eat a high carb diet. That's a bad idea just in general. She should eat as usual except don't eat before the test in the morning. If the test is later in the day she can eat something high-protein/high-fat (eggs or something) in the morning but I don't think you're supposed to eat anything for at least 3 hours before?

This is incorrect.

What exactly is incorrect about it? Don't eat high-protein? Don't fast for 3 hours? In either case, what is the correct information? This is not a helpful comment.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I've never heard to eat a high carb diet. That's a bad idea just in general. She should eat as usual except don't eat before the test in the morning. If the test is later in the day she can eat something high-protein/high-fat (eggs or something) in the morning but I don't think you're supposed to eat anything for at least 3 hours before?

This is incorrect.

What exactly is incorrect about it? Don't eat high-protein? Don't fast for 3 hours? In either case, what is the correct information? This is not a helpful comment.

For the 3 hour test, it is a fasting test. Don't post if you're not sure what you're talking about.

[Anonymous]

OP here: Yes, she's instructed to fast before the test. It's in the morning, so she won't be eating anything after dinner the night before.

Our aim is certainly not to game the test. We want an accurate result. My concern is just that with vague instructions, we want to be sure that we're not getting an *inaccurate* result (false positive) by not preparing for the test properly. I know a three-day high-carb diet is often prescribed before the test, and so I'm wondering what the effect of this is, and whether lower-than-average carb consumption in the days/weeks before the test can lead to a false positive diagnosis of GD.

[Anonymous]

Anonymous wrote:OP here: Yes, she's instructed to fast before the test. It's in the morning, so she won't be eating anything after dinner the night before.

Our aim is certainly not to game the test. We want an accurate result. My concern is just that with vague instructions, we want to be sure that we're not getting an *inaccurate* result (false positive) by not preparing for the test properly. I know a three-day high-carb diet is often prescribed before the test, and so I'm wondering what the effect of this is, and whether lower-than-average carb consumption in the days/weeks before the test can lead to a false positive diagnosis of GD.

Outside of your posts in this thread, I've literally never heard of this.