These six-hour Glucose Tolerance Tests show that some people get distressed when their blood sugar is below of the normal (shaded) range. But since some people suffer distress when their blood sugar is in the normal range but falling rapidly, only one solid conclusion is possible: If dietary improvements resolve the distress, then the cause was hypoglycemia. From Orthomolecular Psychiatry, Ed Linus Pauling, WH Freeman, 1973

Anyone can perform this test upon themselves. The ExacTech RSG complete glucose testing kit for diabetics includes 10 test strips and sells for $29.95 at this writing. Glucola syrup contains the requisite 100 grams of glucose and can be ordered from a pharmacy, or you can dissolve 20 packets of table sugar in water. To make the readings equivalent to the levels in a doctor's lab which tests serum (not the whole blood), add 10%. Plotting the results with any symptoms you experience during the test gives you something to compare with these graphs. However, I'm with Dr Seale Harris:- if symptoms resolve with a low carbohydrate diet, then it was hypoglycemia.