Obesity is a complex and multifactorial chronic disease with genetic, environmental, physiological and behavioural determinants that requires long-term care. Obesity is associated with a broad range of complications including type 2 diabetes, cardiovascular disease, dyslipidaemia, metabolic associated fatty liver disease, reproductive hormonal abnormalities, sleep apnoea, depression, osteoarthritis and certain cancers. An algorithm has been developed (with PubMed and Medline searched for all relevant articles from 1 Jan 2000–1 Oct 2021) to (i) assist primary care physicians in treatment decisions for non-pregnant adults with obesity, and (ii) provide a practical clinical tool to guide the implementation of existing guidelines (summarised in Appendix 1) for the treatment of obesity in the Australian primary care setting.

Treatment pathways should be determined by a person’s anthropometry (body mass index (BMI) and waist circumference (WC)) and the presence and severity of obesity-related complications. A target of 10–15% weight loss is recommended for people with BMI 30–40 kg/m² or abdominal obesity (WC > 88 cm in females, WC > 102 cm in males) without complications. The treatment focus should be supervised lifestyle interventions that may include a reduced or low energy diet, very low energy diet (VLED) or pharmacotherapy. For people with BMI 30–40 kg/m² or abdominal obesity and complications, or those with BMI > 40 kg/m² a weight loss target of 10–15% body weight is recommended, and management should include intensive interventions such as VLED, pharmacotherapy or bariatric surgery, which may be required in combination. A weight loss target of > 15% is recommended for those with BMI > 40 kg/m² and complications and they should be referred to specialist care. Their treatment should include a VLED with or without pharmacotherapy and bariatric surgery.