Writing in this week's issue of the Lancet, US doctors report a "life-threatening complication" of the Atkins diet observed in a 40-year old obese woman.
The patient was admitted to the intensive care unit in a New York hospital with dangerously high levels of acids in her blood caused by starvation, said Professor Klaus-Dieter Lessnau of the New York School of Medicine.
The woman, who had been strictly following the Atkins diet for a month and had lost 9kg, had become increasingly short of breath five days before being admitted to hospital. She had lost her appetite and had vomited four to six times daily.
According to Lessnau and his colleagues, she was suffering from severe ketoacidosis, a condition that occurs when high levels of acids called ketones build up in the blood. Ketones are produced in the liver as a result of diabetes or starvation.
According to the doctors, a low carbohydrate diet such as Atkins can lead to ketone production- in fact, the Atkins diet book recommends regular monitoring for ketones in the urine to confirm adherence to the diet.
"Low-carbohydrate diets for weight management are far from healthy, given their association with ketosis, constipation or diarrhoea, halitosis, headache, and general fatigue to name a few side-effects," said the doctors.
"As researchers and clinicians, our most important criterion should be indisputable safety, and low-carbohydrate diets currently fall short of this benchmark. Professional dietetic associations in the US, Australia and Europe, emphasize eating healthy foods and being physically active."
And although weight loss studies have shown significant health benefits, such as a reduced risk of diabetes, hypertension and reduced risk factors for other metabolic conditions, the current report emphasizes that not all weight loss methods have similar benefits.
Indeed, the position of the American Dietetic Association on weight control is that "successful weight management to improve overall health for adults requires a lifelong commitment to healthful lifestyle behaviors emphasizing sustainable and enjoyable eating practices and daily physical activity."
However, the Atkins foundation said that the diet alone would not lead to such health complications.
"Millions of people are on the diet and don't have problems," said Dr Abby Bloch, vice president for programs and research at the Atkins Foundation.
"Clearly this issue of ketoacidosis is a clinical problem and doesn't occur from dietary issues unless a person has abnormal clinical or metabolic issues," she told FoodNavigator-USA.com.
"We should have moved on from all of this, it should have been put to rest several years ago after a number of studies, both ones conducted on our behalf and also independent ones, confirmed the safety of the diet," she added.
However, this is not the first time that scientists have warned of the dangers of low-carbohydrate diets.
Just last month, research published in the JAMA Archives of Internal Medicine reveals that such diets could be linked to higher levels of LDL or 'bad' cholesterol levels. The findings were drawn from an analysis of five previous clinical studies that compared low-fat to low-carb diets.
But other scientists remain convinced that low-carb is a benefit approach to several health conditions including diabetes and cardiovascular disease.
In January, the Nutritional and Metabolic Aspects of Carbohydrate Restriction conference in New York, examined the role of carbohydrates in the human body - from cell function to blood sugar control.
Papers presented covered the role of carbohydrate control in metabolic syndrome, a precursor of diabetes and cardiovascular disease, and in cardio risk factors like low HDL cholesterol and small LDL lipoprotein pattern.