Jim Ellis, Orlando, Florida: Like many teenage girls, Lee Ann Thill was obsessed with her appearance. A diabetic, she was already suffering from bulimia forcing herself to throw up to lose weight. But it was not enough, and she recently had put on 20 pounds (9 kilograms).

Then one day at a camp for diabetic teens, she heard counselors scold two girls for practicing ''diabulimia'' not taking their insulin so they could lose weight, one of the consequences of uncontrolled diabetes.

Do you not realize you could die if you skip your insulin? the counselor scolded.

But Thill, who has Type 1, or juvenile diabetes, focused on this: Skipping insulin equals weight loss. For the next 17 years, diabulimia was her compulsion.

''I took just enough insulin to function,'' said Thill, now 34.

Today, she worries about the long-term damage that may have come from her weight obsession. At 25, a blood vessel hemorrhage in her eye required surgery. At 28, doctors told her she had damaged kidneys.

''I'm fearful for the future,'' Thill said. ''I feel very strongly that had I taken care of myself, I could have lived as long as anyone without diabetes. I don't think that's going to happen now.''

Diabulimia is usually practiced by teenage girls and young women, and it may be growing more common as the secret is exchanged on Internet bulletin boards for diabetics and those with eating disorders. One expert who has studied the phenomenon estimates that 450,000 Type 1 diabetic women in the United States one-third of the total have skipped or shortchanged their insulin to lose weight and are risking a coma and an early death.

''People who do this behavior wind up with severe diabetic complications much earlier,'' said Ann Goebel-Fabbri, a clinical psychologist at the Joslin Diabetes Center in Boston.

The American Diabetes Association has long known about insulin omission as a way to lose weight. But ''diabulimia'' is a term that has only cropped up in recent years and is not a recognized medical condition, said Barbara Anderson, a pediatrics professor at Baylor College of Medicine in Houston.

Type 1 diabetes is a disorder in which the body's immune system attacks insulin-producing cells in the pancreas. People with this disease produce little or no insulin, so they take shots of the hormone daily.