Some experts, however, believed the case was rare and did not reflect a major health threat associated with lowcarb diets.

"I think this is an isolated case. The idea that serious ketoacidosis could be triggered by a lowcarb diet does not happen very often," said Dr. Paul Clayton, president of the forum on food and nutrition at the Royal Society of Medicine in London.

The patient, who was not identified, was admitted to an intensive care unit for four days after becoming short of breath.

Before being hospitalized, she had lost her appetite, felt nauseous and was vomiting four to six times a day, the doctors wrote in the paper.

Tests confirmed ketoacidosis, a dangerous buildup of acids called ketones in the blood which can lead to patients falling into a coma.

Ketones are produced in the liver when insulin levels fall due to starvation or diabetes.

"Our patient had an underlying ketosis caused by the Atkins diet ... This problem may become more recognized because this diet is becoming increasingly popular worldwide," said Professor Klaus-Dieter Lessnau, who led the team from the New York School of Medicine.

Clayton said that the main problem of high protein diets is in the strain they put on kidneys and the possible risk of renal failure.