"Loading" Diet for GTT?

My doctor and I strongly suspect I have reactive hypoglycemia, and I have been following a no-sugar (as well as other adjustments) diet for about three weeks now.  He has ordered a 5-hour Glucose Tolerance Test to confirm the diagnosis.

For this test, the lab gave me a three-day "loading diet" of things I must eat in the three days preceding the test.  This diet includes sugar specifically (2 tsp/day) as well as potatoes, desserts, and other such foods, which I have been avoiding.  I have never heard of this type of "loading" in relation to the GTT in what I have read.

Going off of sugar has not been easy for me.  I've really struggled with severe fatigue and headaches, and from what I read, this is not uncommon and will pass.  My concern is that three days on this prescribed diet will cause a setback--that is, will put me back to square one in the typical 3 to 5 week "feeling crummy" phase of a hypoglycemic diet.  

Is this type of "loading" diet a necessary part of the GTT?  Is it likely that three days of eating this way will mean starting over in the "gets worse before it gets better" process of a hypoglycemic diet?

Thanks so much.

[Anita Ramsetty, MD]

Hi,
The 5-hour glucose tolerance test is not used very frequently anymore for diagosing reactive hypoglycemia, but it was in the past. Often if dietary changes have helped(and this is the mainstay of treatment anyway), then we do not require a GTT.
I am not aware of the "loading" you described as part of the pre-test preparations, and so I am also unsure of what this may(or may not) do to your system prior to the test. I suggest talking it over with your doctor again before the test. My concern also is your possibly having symptoms during those two days even prior to the test.  

Hope this helps. Take care.

[macgyver16]

Usually the usual prep for GTT the patient is placed on a high carbo diet 3 days before testing and withold medications such as hypoglycemic drugs, steroids, caffein, insulin 12 hours before testing.. for GTT

[Anita Ramsetty, MD]

Hi,
There is some debate about this "loading concept" which was done frequently in the past. Some studies had found that low carbohydate diets caused false positives on the OGT test, so high carb was recommended instead. Other studies showed no difference if regular diet was used. Many physicians now are simply recommending a "normal diet" without carbohydrate restriction instead frank loading.  My recommendation is just to discuss it with your doctor if you are still unsure and concerned about how you will feel during the loading phase.
Take care.