What are the dietary recommendations for the three days preceding the oral glucose tolerance test (OGTT)?
—G. Tadros, MD, Wilmington, Del. 

Many centers offering the OGTT recommend eating a balanced diet containing at least 150-200 g of carbohydrate per day for three days before the test. However, a study of pregnant women screened for gestational diabetes suggests that this diet may be unnecessary as it does not significantly affect the results of testing and may delay the diagnosis of gestational diabetes (Am J Obstet Gynecol. 2000;182:1052-1054). It is not clear whether these findings are equally applicable to other patient populations, but I suspect they are.
—Daniel G. Tobin, MD