In the Hall of Fame of medical myths, hypoglycemia holds an honored place. If we had a dime for every time the term has been bandied about inaccurately, we could have retired long ago to Tahiti.

Part of the problem lies in the signposts pointing toward hypoglycemia: fatigue, weakness, recurrent headaches and extreme hunger that leads to binges of overeating. These symptoms are somewhat vague and certainly common, and people are always looking for labels to explain what they experience.All too often, we've heard of individuals diagnosing themselves as having hypoglycemia - or low blood sugar - with only a rudimentary understanding of what that means. In reality, the condition is both rare and difficult to diagnose.

Idiopathic hypoglycemia is the presence of very low blood sugar without any demonstrable organic disease. Sometimes it indicates a serious medical problem: congenital enzyme deficiencies, involvement of the liver, the adrenal glands or pituitary gland, the central nervous system or the pancreas. Cancer of the pancreas, which leads to overproduction of insulin, is in fact the single most dangerous cause of hypoglycemia. Very occasionally the condition results from an overactive pancreas rather than from disease. And in infants, acute hypoglycemia may signal that the baby is unable to gain access to energy reserves of glycogen (animal starch) stored in the liver.

What happens during a hypoglycemia attack? Following a meal high in simple sugars, the pancreas reacts by flooding the body with insulin. Sending a surge of glucose into the body cells, the insulin causes blood-sugar levels to drop dramatically. The effect resembles that which occurs when diabetics get too much insulin, and the symptoms are also similar: weakness, trembling and extreme hunger. In severe case there may be hysterical symptoms, convulsions and ultimately coma.

Now, let's say that you feel tired and weak much of the time, you have frequent headaches, and that you deal with unexplained pangs of hunger by bingeing on sugary foods. The last thing you should do is to assume that you have hypoglycemia. Diagnosis of the condition is no do-it-yourself proposition.

In fact, it requires a special five-hour test. The patient drinks a concentrated glucose solution, after which the rise and fall of blood sugar is carefully monitored at intervals. Normally, it takes about 3 hours for blood glucose to drop back to fasting levels. If diabetes is present it will take longer. By contrast, where hypoglycemia exists, it could take as little as 30 minutes. The surge of insulin removes blood sugar very rapidly. Low blood sugar coupled with the simultaneous onset of symptoms is the sign of hypoglycemia.

Supposing you were found to have the condition, the next step would be treatment. The goal would be to supply the body with glucose - which we need for fuel - without overstimulating the pancreas and sending the body on an insulin-induced roller-coaster ride as blood sugar levels alternately soar and plummet.

The classic diet suggested for treatment used to be low in carbohydrate, with little or no readily absorbable sugar, and heavy reliance on protein and fat. Candy, jellies and jams, and sugary drinks and desserts were all ruled out. Meat, fish, poultry or cheese appeared at every meal, and vegetable oil was used in salad dressing. In severe cases the daily intake was spread out over small meals. And to be prepared for a sudden attack, the patient was advised to carry crackers and cheese at all times.

The recommended regimen has been updated today to include more complex carbohydrates, such as whole-grains rich in fiber, which the body uses slowly enough to avoid provoking undesirable symptoms.

Even though it can be treated, nobody would choose to suffer from hypoglycemia. The question then becomes, Why are so many people so quick to assume that they have it? If you are experiencing the symptoms - weakness and fatigue, headaches, hunger pangs and bingeing on sugary foods - you may indeed have a problem.

Chances are, however, that it is something other than hypoglycemia. Only a through examination, and your physician, can tell for sure.

QUESTION: On different infant foods, the labeling information seems inconsistent with respect to heating in a microwave. Are there some general guidelines?

ANSWER: The major potential problem in using a microwave oven to heat baby foods is that, like other foods, they can develop hot spots. These could cause serious burns. Some foods are more susceptible to forming hot spots than others. It is crucial to stir warmed baby food thoroughly and to check to make sure it's not too hot.