The ketogenic diet has shaped up as the biggest weight-loss trend of the last few years.

What’s not being talked about: Even though there are positive anecdotal reports on using this high-fat, very-low-carbohydrate diet for weight loss—and research is promising (see below)—few people know about its current and potential uses for neurological conditions and ­other chronic diseases…

NEUROLOGICAL CONDITIONS

• Epilepsy. Diet therapy was a common epilepsy treatment until the development of antiseizure drugs in the 1930s. Now researchers are taking a second look at the ketogenic diet because some patients with epilepsy are drug-resistant—that is, they have failed to respond to two different medications…and have less than a 5% chance of becoming seizure-free with the use of additional drugs.

Scientific evidence: Research has confirmed that 40% to 50% of adults with epilepsy will improve on the diet with the most benefits seen in patients who stick with it.

Among the many possible mechanisms, the diet is thought to dampen the brain-cell “excitability” that’s associated with seizures. It also improves the balance of intestinal bacteria, which appears to provide seizure protection.

The ketogenic diet doesn’t replace anti-epilepsy drugs—most patients will continue to take medication, although many will require fewer drugs and/or a lower dose. I advise a variety of epilepsy patients to try the diet for at least three months. If it’s effective, they stick with it. If not, they slowly resume their consumption of carbohydrates, under the supervision of a medical professional or nutritionist.

• Brain cancer. Glioblastoma, a type of malignant glioma, is the most frequently diagnosed primary brain tumor. Early research suggests that a ketogenic diet could help patients with this type of cancer, particularly when combined with radiation and/or other treatments.

In laboratory studies, animals given a ketogenic-like diet showed improved survival times of 20% to 30%. Small studies—many of them case reports (descriptions of individual patients)—have shown improvements in disease progression and survival.

The diet may help because the cells that fuel cancer depend on glucose as an energy source. When you take away glucose with a ketogenic diet, cancer cells may lose the ability to proliferate.

My advice: If you or a loved one has been diagnosed with this type of cancer, ask your doctor if a ketogenic diet might help—and if he/she recommends participating in one of the clinical trials listed at ClinicalTrials.gov. (There are also trials that focus on the use of this diet for other types of cancer.)

• Alzheimer’s disease. Like the cancer cells described above, the amyloid deposits that are the hallmark of Alzheimer’s may depend on high levels of glucose in the blood.

In laboratory studies, animals given extracts that put their bodies into a ketosis-like state (see below) showed improved learning and memory. Studies involving Alzheimer’s patients or those with mild cognitive impairment have shown that people given similar extracts had improvements in working memory and visual attention.

My advice: Because the research is too preliminary to conclude that the diet is—or isn’t—effective for this purpose, I wouldn’t advise Alz­heimer’s patients to try the diet without close medical supervision. But if you’ve been diagnosed with Alzheimer’s—or have a high risk of developing it—you might want to discuss it with your doctor.

OTHER USES

• Weight loss. The ketogenic diet is a far cry from the plant-rich ­diets that most experts recommend for weight loss. In its most restrictive form, it limits many vegetables, fruits, beans and grains—all of the foods that can help you lose weight.

Yet people who switch to a ketogenic diet (the plans for weight loss are somewhat less restrictive than those used for some of the conditions described above) do lose weight—and they lose it quickly.

Caveats: Most experts agree that people who follow the diet can lose weight. But it doesn’t appear to be any more effective than other, more conventional diets, and the drop-out rate is probably much higher.

• Diabetes. People with diabetes are usually advised to eat less fat because weight loss and a lower-fat diet have been thought to go hand in hand. But experts are taking ­another look at the ketogenic diet for diabetes control. Reasons: Not only can the diet promote weight loss, but there’s some evidence that it improves insulin sensitivity and lowers blood sugar.

Caution: People with diabetes who follow a ketogenic diet have an increased risk for diabetic ketoacidosis, a life-threatening condition due to elevated blood sugar and blood acids (ketones).

HOW THE DIET WORKS

The term “ketogenic” has become a catchall phrase for any high-fat, low-­carbohydrate diet. But in the medical community, the diet calls for a severe restriction of carbohydrates and high amounts of fat. The requirements are so rigorous that the diet should be attempted only with the supervision of a doctor, as with any medical therapy.

How it works: Normally, blood sugar (glucose) from carbohydrates is your main source of energy. But when glucose is restricted, your body starts breaking down fat, a process that releases ketone bodies into the bloodstream. Cells use ketone bodies as an alternative fuel source until you start eating carbohydrates again.

If you stay on the diet long enough, the body enters ketosis. (You experience a mild form of ketosis when you’ve gone all night without food.) Ketosis mimics a starvation state—it triggers metabolic changes, including those that promote weight loss and improve insulin sensitivity.

The diet emphasizes foods high in fat, moderate in protein and low in carbohydrates (eggs, cheese, avocados, butter, olive oil, cream, bacon, steak, salmon, sardines, nuts, seeds, etc.).