Reactive hypoglycemia is a medical term describing recurrent episodes of symptomatic hypoglycemia occurring 2-4 hours after a high carbohydrate meal (or oral glucose load). It is thought to represent a consequence of excessive insulin release triggered by the carbohydrate meal but continuing past the digestion and disposal of the glucose derived from the meal.
The prevalence of this condition is difficult to ascertain and controversial, because a number of stricter or looser definitions have been used, and because many healthy, asymptomatic people can have glucose tolerance test patterns said to be characteristic of reactive hypoglycemia. It has been proposed that the term reactive hypoglycemia be reserved for the pattern of postprandial hypoglycemia which meets the Whipple criteria (symptoms correspond to measurably low glucose and are relieved by raising the glucose), and that the term idiopathic postprandial syndrome be used for similar patterns of symptoms where abnormally low glucose levels at the time of symptoms cannot be documented.
Although symptoms vary according to individuals' sensitivity to the elevation and decline of glucose levels, some of the more common symptoms are:
- craving sweets
- increased appetite
- epileptic-type response to rapidly flashing bright lights
There are different kinds of reactive hypoglycemia: 
1) Alimentary Hypoglycemia (consequence of dumping syndrome; it occurs in about 15% of people who have had stomach surgery)
3) Hormonal Hypoglycemia (due to lack of some hormones; i.e., hypothyroidism)
4) Helicobacter pylori-induced gastritis (some reports suggest this bacteria may contribute to the occurrence of reactive hypoglycemia)
5) Congenital enzyme deficiencies (hereditary fructose intolerance, galactosemia, and leucine sensitivity of childhood)
6) Idiopathic reactive hypoglycemia
7) Late Hypoglycemia (Occult Diabetes; characterized by a delay in early insulin release from pancreatic B cells, resulting in initial exaggeration of hyperglycemia during a glucose tolerance test)
To check if there is real hypoglycemia when symptoms occur, you can have an OGTT, or even more accurate for this kind of diagnosis, a "breakfast test".  Then, additional tests may be applied to see if there is another disease (i.e. hypothyroidism) causing the reactive hypoglycemia.
To relieve reactive hypoglycemia, some health professionals recommend taking the following steps:
- Eat small meals and snacks about every 3 hours.
- Exercise regularly.
- Eat a variety of foods, including meat, poultry, fish, or non-meat sources of protein, foods such as whole-grain bread, fruits, vegetables, and dairy products.
- Choose high-fiber foods and food with a moderate-to-low glycemic index.
- Avoid or limit foods high in sugar, especially on an empty stomach.
- Avoid alcohol, caffeine, and highly starchy foods such as white rice, potatoes, corn, and popcorn (all very high on the glycemic index).
- Adding soluble fibers (e.g., 5 to 10 grams of hemicellulose, pectin, or guar gum) to a meal may help to relieve symptoms, especially in dumping syndrome. 
Your doctor can refer you to a registered dietitian for personalized meal planning advice. Although some health professionals recommend a diet high in protein and low in carbohydrates, studies have not proven the effectiveness of this kind of diet for reactive hypoglycemia. If the diet does not provide a relief in symptoms, there are some medications which can be useful in reactive hypoglycemia, and that should be administrated only by a physician.
Postprandial Syndrome and Adrenergic Postprandial Syndrome
If there is no hypoglycemia at the time of the symptoms, this condition is called Postprandial Syndrome. It might be an "Adrenergic Postprandial Syndrome" - the glycemia is normal, but the symptoms are caused through autonomic adrenergic counterregulation. Often, this syndrome is associated with emotional distress and anxious-behaviour of the patient  . Dietary recommendations for reactive hypoglycemia can help to relieve symptoms of postprandial syndrome.
- ↑ Açbay O, Celik AF, Kadioğlu P, Göksel S, Gündoğdu S (1999). "Helicobacter pylori-induced gastritis may contribute to occurrence of postprandial symptomatic hypoglycemia". Dig. Dis. Sci. 44 (9): 1837–42. PMID 10505722.
- ↑ "eMedicine - Hypoglycemia : Article by Vasudevan A Raghavan". Retrieved 2007-07-06.
- ↑ "Postprandial Hypoglycemia (Reactive Hypoglycemia)". The Hypoglycemic states - Hypoglycemia. Armenian Medical Network. 2007. Text " Umesh Masharani, MB, BS, MRCP(UK) " ignored (help)
- ↑ [http://www.uni-duesseldorf.de/MedFak/insulinoma/english%20homepage/mainpage/subpage/Epostpran_hypo.htm#APS "postprandiale Hypoglyk�mie"]. Retrieved 2007-07-06. replacement character in
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- Overview at Mayo Clinic
- Dumping Syndrome Overview at Mayo Clinic
- Article about hypoglycemia at eMedicine
- Research about reactive hypoglycemia
- Overview about the causes of reactive hypoglycemia
- Research about suspected reactive hypoglycemia associated with B-adrenergic hypersensivity and emotional distress
- Açbay O, Celik AF, Kadioğlu P, Göksel S, Gündoğdu S (1999). "Helicobacter pylori-induced gastritis may contribute to occurrence of postprandial symptomatic hypoglycemia". Dig. Dis. Sci. 44 (9): 1837–42. PMID 10505722.
- Classification and possible causes of reactive hypoglycemia (article of 1972; may not be in accord with current medical practice)