Q. When I skip meals I get shaky, irritable and anxious. I also get lightheaded and can't think straight. Can you explain why this happens? Is there anything I can do to prevent it?

A. It sounds like you have low blood sugar, also known as hypoglycemia. This condition is common among my patients, and the remedy can be simple.

In conventional medicine, hypoglycemia is typically diagnosed by measuring the level of sugar (glucose) in your blood after a 12-hour fast. This is known as your "fasting blood sugar." If it's below 60 milligrams per deciliter, a diagnosis of hypoglycemia is made. There are alternatives, however, to this approach to diagnosing hypoglycemia. One of the most helpful derives from what is known as "functional medicine."

As a whole, functional medicine reflects principles that have long been central to naturopathic medicine. It focuses on early intervention and optimal health, as well as physiologic imbalances that could lead to disease. It also places special emphasis on your symptoms; the fact that you have them indicates that you aren't healthy. (A healthy person who skips meals experiences none of your symptoms, but merely feels hungry.)

Functional medicine provides a different, more holistic definition of hypoglycemia — one that considers subtleties that conventional medicine may overlook. According to this approach, you may be diagnosed with hypoglycemia if you have the symptoms you describe and your fasting blood sugar is below 85 mg/dL. This definition applies to people who have many of the symptoms, but whose conditions may not be as clinically obvious on blood tests. It often allows for early detection and treatment, which can be critical with hypoglycemia.

The earlier hypoglycemia is treated, the sooner you can prevent a host of conditions that could result from the chronic stress you put on your body by not eating good food regularly. These include insomnia, fatigue, exaggerated PMS, depression and low immunity.

Symptoms of hypoglycemia occur because your brain needs a constant supply of glucose to function. Your brain weighs only a few pounds, yet uses two-thirds of your body's glucose. Here are three simple steps you can take to support your body and prevent hypoglycemia: