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12 Dec 2016

By Dr Timothy O'Dowd, an obstetrician, gynaecologist and IVF specialist, working in private practice at Pindara Private Hospital, Gold Coast

Doctors are expected by patients to give dietary advice, to help with setting realistic weight goals and to give exercise recommendations. Yet, for various reasons, Australian doctors do not appear to be following recommended suggestions to monitor and manage obesity. The ability to give good general nutrition advice should be a central component of patient care.

The three pillars of evidence-based practice are the integration of the doctors’ expertise with the patient’s values and preferences, and the judicious use of the best available evidence. The aim of this article is to address the question of whether doctors have the training and knowledge (expertise) to give nutrition advice; and what the “best available evidence” is in regards to nutrition.

Do doctors have the expertise to give nutrition advice?

Through the intensive study of biochemistry, physiology, pathology, and the patho-physiology of disease, doctors obtain a solid foundation of nutrition and its effects on the human body. After some years in practice, doctors gain enormous experience dealing with various disease states and the contribution of diet to prevention and treatment.

As a consequence, doctors are uniquely qualified to give nutrition information to patients.

What is the best available evidence?

The Australian Dietary Guidelines (ADG 2013) and other international dietary guidelines tend to follow a similar paradigm. Their recommendations over the last 40 years have been with the express purpose of improving community health. However, governments and medical professionals remain concerned about the continued rise in rates of obesity, diabetes and cardiovascular disease. 

The task of determining what is the best available evidence has been complicated by claims from some that medical research is less-than-perfect, and that evidence-based medicine has been hijacked and is in crisis. Moreover, researchers caution that it is difficult to attribute the occurrence of a chronic disease to any single food or nutrient item and, consequently, any observed relationship between a food or nutrient item and chronic disease must be interpreted with care and replicated in multiple studies. And patients are assailed with nutrition suggestions from a wide array of sources, including diet organisations, books, television and the internet, and many look to their doctor for definitive advice.

Doctors, in their turn, rely on academia to analyse and rate the enormous pool of nutrition research that is produced every year, and to compress it into recommendations and guidelines. Several Australian organisations recommend following the ADG 2013, including the Royal Australian College of General Practitioners, the Dietitians Association of Australia, and other organisations who promote low saturated fat intake and reduced fat dairy products.

While this would appear to suggest a degree of consensus on what is the best evidence, support for national dietary guidelines, including ADG 2013, is far from unanimous. Increasingly there are articles questioning long-held beliefs, in particular in relation to the macronutrient percentages (protein, fat, carbohydrate) in the diet. There is major dissent about whether our diet should be composed of lower or higher carbohydrate, and lower or higher fat content, especially saturated fats.

The medical profession and nutrition advice

Our patients expect us to include dietary advice in the management of their health.

The medical profession should strive to reclaim and protect the central role of doctors in discussing and advising patients regarding nutrition in their overall care. Given the importance of nutrition to health, medical schools and the various specialty colleges have a responsibility to increase emphasis on nutrition science from the biochemistry, physiology and pathology sciences, in undergraduate and postgraduate education, including at annual scientific meetings.

Doctors who delegate their role regarding diet advice for their patients are disregarding the fact that nutrition is recognised as a major modifiable factor for the prevention and management of obesity, diabetes, heart disease and other chronic disorders including dementia, cancer and non-alcoholic fatty liver disease.

Nutrition research should be considered a complex ‘work in progress’. The ADG 2013 can be accepted as a substantial interim report reflecting the considered views of the academics who wrote the guidelines. While there is considerable support for the guidelines from important medical and dietician organisations, adherence to these guidelines cannot be regarded as mandatory.

Rather than relying solely on ADG 2013, or indeed referring directly to a dietitian, doctors could broaden their understanding of the issues confronting their patients.


Good nutrition is important for general health and the prevention or amelioration of obesity and many chronic diseases.

The medical profession should reclaim its central role in all aspects of patient care and regard nutrition advice as a central component of care. This is what our patients expect.

Doctors have the training, experience and expertise to consider giving nutrition advice to their patients.

At present, deciding what is the “best available evidence” from the clinical research in nutrition is contentious. The evidence, such as it is, should be limited to assisting the clinical decision-making, rather than overriding it.


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Published: 12 Dec 2016