Head of clinical obesity research at Baker IDI Heart and Diabetes Institute John Dixon said National Health and Medical Research Council guidelines released in June last year contained the "potentially dangerous" implication that nutritional problems should only be assessed after symptoms developed including muscle wastage and bone pain.

The council revised the guidelines in October after Professor Dixon raised concerns, and it now advises health professionals simply to assess nutritional status "including for micronutrient and vitamin deficiencies that might develop over time".

Professor Dixon said the revised guidelines remained inadequate, with high-quality guidance required to care for patients after bariatric surgery. Writing in the Medical Journal of Australia, he said energy intake was markedly reduced in such patients and absorption of micronutrients such as iron and calcium could be impaired.

He said all bariatric procedures required excellent nutritional support, monitoring and supplementation and waiting for symptoms of deficiencies to appear could result in lasting damage.

Professor Dixon said nutritional issues were a critical downside to bariatric surgery "and should be front of mind whenever doctors, nurses, dietitians or any other health professionals interact with a patient after surgery".

He said US guidelines he helped develop for groups including the American Association of Clinical Endocrinologists provided detailed advice on monitoring nutrition in patients after bariatric surgery, including tests to check levels of vitamins and minerals and other changes in the blood.

A spokeswoman for the council said the committee decided to remove references to specific nutritional complications after bariatric surgery given the potential for misinterpretation raised by Professor Dixon.

"The level of detail was unnecessary in the context of a guideline written for primary care," she said.

"The guidelines now clearly state that 'individual monitoring and [bariatric surgery] follow-up protocols should be determined by the appropriate specialist team or surgeon, in consultation with the primary care health professionals involved' – a point made by Professor Dixon in his article."