The popular mantra to lose weight by diet and exercise sometimes isn’t enough, argues Dr Julie Manasseh.

We know obesity is a major contributor to health burden. Two-thirds of the Australian population are either overweight or obese, and these are drivers for 22 diseases including diabetes, cardiovascular disease, musculoskeletal conditions, kidney disease, asthma, dementia and certain cancers.

Dr Julie Manasseh

In 2019, the financial burden of obesity was estimated to be $11.8 billion, with $5.4 billion in direct health costs and $6.4 billion in indirect costs.

Obesity is now recognised as a chronic disease of complex biopsychosocial aetiology which has only occurred in the past three decades. Despite of its overwhelming contribution to the burden of non-communicable diseases (NCDs), it has taken a long time for the medical profession to recognise that the management of obesity requires specialised training and skills.

Obesity is a chronic disease, not a lifestyle choice

The message from public health and medical authorities has been that obesity can be addressed by diet and exercise or the “eat less, move more” philosophy.

The idea that obesity can be treated by diet and exercise alone is a fallacy, given that obesity is a chronic disease which involves multiple contributing factors including genetics, stress, sleep and lifestyle factors, mental health, medical conditions and medications in addition to diet and exercise. 

Furthermore, we now know that once obesity has been established, biological adaptations come into play to rigorously ‘defend’ the body’s higher set point weight from any attempts at weight loss.

Hence attempts to lose weight by diet and exercise tend to have limited short-term success, as the body responds to weight loss by increasing hunger hormone signals to increase appetite, and by lowering resting metabolic rate so that less energy is used for vital metabolic functions. 

These biological adaptations to weight loss are designed to cause weight regain, which inevitably occurs as the ‘diet’ cannot be sustained in the long-term.

With the recognition that obesity is a chronic complex disease and not a lifestyle choice, and also the evidence which shows that weight loss of 5-10% or greater can improve obesity-related complications, it makes sense that a doctor who has specialty training in obesity and weight loss could improve obese patients’ health trajectory.

How does an obesity physician do to help patients lose weight?

The obesity physician makes a thorough medical and weight-focused assessment of the patient, including factors that have led to weight gain and obesity-related health complications.

Assessment of stress, sleep, mental health, diet and exercise are critical, as these all influence weight. 

My approach is to first address underlying factors that have led to weight gain such as poor sleep, depression/anxiety or menopausal symptoms. Once there are signs of improvement in the problem areas, I focus on weight loss using weight loss pharmacotherapy targeted to the patient’s eating behaviour profile. 

There are regular reviews to monitor weight loss progress that involve coaching in making behavioural changes to improve diet, exercise, sleep and stress management.

The goal is to achieve 10% or greater loss of body weight and to maintain this lower weight in the long term.

The multidisciplinary team model of obesity management is important when the patient presents with specific problems that require the input of another health professional.

Examples would be patients with deeply entrenched problem-eating behaviours such as binge eating disorder, who would benefit from seeing a psychologist, or those with specific dietary restrictions such as food intolerances that may require advice from a dietitian. 

Who can benefit from medical weight loss?

Given that overweight and obesity is a major contributor to almost every medical condition, it would follow that if one can achieve and sustain weight loss of ideally 10% or greater, then there would be potential improvement in comorbidities such as diabetes, hypertension, cardiovascular disease and sleep apnoea, improvement in fertility and pregnancy outcomes, reduction in surgical complication rates and much more.

Studies have shown that behavioural intervention (diet and exercise) can only achieve 3-10% weight loss with a very low incidence of long-term weight maintenance (50-70% weight regain within two years).

However, with the advent of new ‘game-changer’ weight loss medications in the past few years, it is now possible to achieve 10-25% weight loss with the addition of targeted pharmacotherapy to behavioural intervention – that is, medical weight loss.

With the evidence to date that diet and exercise alone has failed to make any impact of the two thirds of the population that is overweight or obese, it is both exciting and long overdue that medical weight loss in the hands of a trained obesity physician is now able to deliver significant weight loss that can improve health outcomes. 

ED: Dr Julie Manasseh is a GP with special interests in obesity and weight loss.