Question from San Diego, California, USA:

I have had several episodes of what I think is low blood sugar. They have always happened under the following conditions: I’ve been dieting for a few days, about 1200 calories a day, reducing, but not eliminating, carbohydrates. Then, I exercise, walking or swimming. After about a half hour of exercise, the symptoms start. They are pretty severe and include shaking, sweating, extreme hunger, anxiety, weakness, and feeling like I might pass out. Each time, I have immediately eaten some carbohydrates and protein, for example, a glass of orange juice and a piece of cold chicken. Eating resolves the worst symptoms, but I feel tired the rest of the day. This has happened about four times.

I’ve been able to prevent the worst episodes by eating frequently and making sure I eat shortly before I exercise. But, I still have milder episodes of shaking, sweating, and feeling odd if I go too long without eating. I have to eat something right before I go to bed, but, even then, I sometimes wake up at night feeling hungry and a bit anxious. Since this has been going on, I feel fatigued much of the time. Do you have any idea what this might be, or what should be investigated?