Stephen Leeder

AMONG the 70 000 artefacts that grace the Hong Kong Heritage Museum are glazed earthenware statuettes from the Tang Dynasty (618–907 AD) of plump women of court who found favour in the eyes of the emperor and his colleagues.

It was good to be fat, just as in the Pacific Island nations where fat was once considered beautiful.

Setting aside the variable aesthetics of fat, the medical facts are not as clear-cut as some might believe.

There is little evidence that fatness below a body mass index (BMI) of 30 kg/m2 does much harm. Over 30 the risks begin to accumulate — but even still, it remains a crude measure. Some obese people may be as metabolically healthy as those with a BMI under 25.

In reality the majority of people who agonise about their weight are not obese. These are the people whose weight oscillates. They pay to attend weight loss centres, they make New Year resolutions. They eat strange foods like kelp and sage. They starve, they meditate, they weep and seek medications.

Before suggesting to plump patients a course of action, we might first ask: do we know everything we need to know about overweight and about preventing obesity?

The answer? Far from it. You don’t have to look any further than the Foresight Obesity Maps, which highlight the non-conventional influences on the problem, to understand why. We live in an obesogenic environment — it is important to acknowledge that obesity is complex and is far more complicated than being “lazy” or “undisciplined”.

While we tend to focus on the individual and his or her eating and physical activity behaviours, the reality is much more complex. The influence of maternal nutrition during pregnancy and perinatal exposure to certain foods is known from animal experiments and human observation to predispose the offspring to overweight and obesity. Epigenetic programming of appetite and metabolism has been posited as one mechanism.

Then there is the interesting observations made by Professor Stephen Simpson and his colleagues that a wide range of animals eat to achieve a specific protein intake. If the ratio of carbohydrates to protein is excessive, we get fat.

Where does all this leave the GP who wishes to help patients with their weight?

Perhaps the most important thing is to listen first and talk second. Gentle reassurance, exploration of diet, seeing whether physical activity can be built into more of the day may be appropriate. But it is worth remembering there are many less affluent parents for whom fancy food is expensive and physical activity over and above what they do while working is not feasible.

Unfortunately, there is plenty of evidence to suggest that physicians, medical students, nurses, dieticians, exercise specialists and other health professionals manifest an attachment to harmful weight-based stereotypes.

Studies of weight bias have shown many health professionals hold negative attitudes towards obese patients and may believe them to be lazy, non-compliant, undisciplined, unsuccessful and unintelligent.

Weight bias does not go unnoticed by patients and may explain why fewer obese persons, compared to those who are thin, seek appropriate preventive screening for cervical, breast and colorectal cancer.

For many health professionals additional training in this area is needed. The Rudd Centre for Food Policy and Obesity at Yale University recognises this and now offers a course for medical practitioners on weight bias in clinical settings.

As health professionals we should be realistic about our weight loss expectations for patients. Aside from bariatric surgery, we really haven’t had much success in finding a weight loss strategy that works and is sustainable. Yo-yo dieting may even be harmful.

In fact, the WHO now recommends counselling patients to set a weight loss goal of up to 10% of body weight rather than their “ideal” weight.

That makes weight loss more achievable for patients and the good news is that even a 5%–10% reduction in weight can reduce health risks, such as diabetes and other diet-related chronic disease.

Professor Stephen Leeder is the director of the Menzies Centre for Health Policy at the University of Sydney. Ms Shauna Downs is a PhD candidate at the centre.

Posted 29 October 2012

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