Idiopathic postprandial syndrome, colloquially but incorrectly known by some as hypoglycemia, describes a collection of clinical signs and symptoms similar to medical hypoglycemia but without the demonstrably low blood glucose levels which characterise said condition.
People with this condition suffer from recurrent episodes of altered mood and cognitive efficiency, often accompanied by weakness and adrenergic symptoms such as shakiness. The episodes typically occur a few hours after a meal, rather than after many hours of fasting. The principal treatments recommended are extra small meals or snacks and avoidance of excessive simple sugars.
The symptoms include many of the symptoms associated with milder degrees of hypoglycemia, especially the adrenergic symptoms, but do not progress to objective impairment of brain function, seizures, coma, or brain damage.
The term idiopathic postprandial syndrome, which literally means a syndrome that occurs after eating (postprandial) and of unknown cause (idiopathic), was coined in an attempt to reserve the term hypoglycemia for those conditions in which low glucose levels could be demonstrated. It was offered as a less confusing alternative to functional hypoglycemia and as a less pejorative alternative to "nonhypoglycemia" or "pseudohypoglycemia".
The syndrome resembles reactive hypoglycemia except that low glucose is not found at the time of symptoms.
The common usage of the term "hypoglycemia" was noted and countered by doctors writing in the Journal of the American Medical Association in the 1970s:
The author said "a cult has developed, consisting of a believing public aided and abetted by 'nutritionists', medical journalists, and a host of physicians."
These doctors cautioned against the over-diagnosis of reactive hypoglycemia. They said "both physicians and the public deserve major re-education."