By Ben Harder, Special for USA TODAY
For a month that tested her determination, Marilyn Deaton dined on little but 
fat. The recipes she prepared included eggs baked with gobs of cream cheese, 
small portions of fish outweighed by butter, oil and mayo, and ground beef 
mixed with so much heavy cream that it ran a light brown.
"I can't stand things that are soft and slimy," says Deaton, 60, of New York. 
She missed "crunchable stuff," such as carrots, she says.
Deaton has Parkinson's disease. The disagreeable diet was an experimental 
treatment prescribed by her doctors. Four other Parkinson's patients followed 
the same menu.
The results, which included modest improvements in balance, tremors and mood, 
were encouraging but too preliminary to prove an effect, says Theodore 
VanItallie of St. Luke?s-Roosevelt Hospital Center in New York. VanItallie 
and his colleagues published their findings last year in the journal 
Neurology.
Their trial and other recent studies hint that a diet nearly devoid of protein 
and carbohydrates might temper symptoms of several neurodegenerative 
disorders, including Alzheimer's and Lou Gehrig's disease, VanItallie says. 
Researchers suspect that such a high-fat diet also could stall brain tumors 
and help patients with certain other health problems — if it doesn't cause 
strokes along the way.
Though such a solution may sound far-fetched, a similar diet has been used 
since the 1920s to treat severe epilepsy. Numerous studies, most of them in 
children who had exhausted other options, have since found that it reduces 
seizures.
There's scant clinical evidence to address whether the plan, called the 
ketogenic diet, has wider therapeutic promise. Researchers aren't sure how it 
works against epilepsy, and they hold various theories about why it might, or 
might not, help in other disorders.
Some of the benefits result from a shift in the brain's metabolism from blood 
sugar, the body's main fuel, to ketone bodies, a secondary energy source that 
is a byproduct of fat metabolism, says Richard Veech, a physician and 
biochemist with the National Institutes of Health in Bethesda, Md.
But, Veech says, "while VanItallie has shown that (the ketogenic diet) works, 
as a practical matter, one can't recommend it." 
The obvious downside 
Consequences of high fat intake, heart problems for one, could offset the 
diet's hypothetical benefits in some people, Veech says. In any case, the 
daunting challenge of maintaining the unpalatable regimen makes it unlikely 
to catch on. 
"Most people would have a very hard time following this diet," says Cathy 
Non-as, the dietitian at North General Hospital in New York who designed 
Deaton's plan. The plan requires that 90% of the patients' calories come from 
fat and just 8% from protein. In the average American diet, fat makes up 33% 
of calories, and protein accounts for 15%.
When a person fasts or subsists mainly on fat, blood sugar declines. The liver 
responds by converting fatty acids into ketone bodies, which normally 
circulate in the blood at low levels, rising as time passes since a person's 
most recent meal, when glucose is abundant.
Popular low-carb diets, such as Atkins, may generate some ketone bodies, but 
not necessarily enough to have a therapeutic benefit, VanItallie says. 
Ketone bodies can accumulate to dangerous levels, in diabetics, for example, 
and turn the blood acidic. But moderately elevated levels are theoretically 
beneficial in a range of circumstances, Veech says.
Lab studies and a few desperate medical cases lend some support to that 
notion. For example, when added to intravenous resuscitation fluids in place 
of a typical ingredient, ketone bodies also reduce organ damage after major 
blood loss, says hematologist C. Robert Valeri of the Naval Blood Research 
Laboratory in Plymouth, Mass. He and his colleagues demonstrated that in 
pigs.
Other teams have shown that the molecules protect mice against neurological 
changes linked to Parkinson's and Alzheimer's.
Last month, researchers at Mount Sinai School of Medicine in New York reported 
similar findings for Lou Gehrig's disease, or amyotrophic lateral sclerosis. 
Giulio Pasinetti of Mount Sinai says his team is launching a trial to treat 
patients with the disease.
In an older report, a ketogenic diet appeared to slow tumor growth in two 
children with inoperable brain cancer. Neurobiologist Thomas Seyfried of 
Boston College later demonstrated the effectiveness of that approach in mice.
Most brain tumor cells, Seyfried says, "can't burn ketones for energy," so 
elevating ketone levels and simultaneously reducing blood sugar may starve 
the tumors while nourishing healthy cells.
A 'lite' version 
VanItallie and Non-as are gearing up for a new Parkinson's trial that will 
test a hybrid of the 90%-fat regimen and the Atkins diet. They've invited 
their former volunteers to participate.
Deaton says her Parkinson's symptoms improved during the original trial, which 
was conducted in 2003. And losing 26 pounds was a bonus, she says. But even 
with a more lenient menu on the table, she doesn't plan on signing up again. 
She's trying a more conventional weight-loss plan. It lets her eat carrots. 
Posted 5/14/2006 7:56 PM ET 

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