What is the best way to address the obesity epidemic? Several experts debated the subject in the most recent issue of the British Medical Journal. 

Researchers from the Children's Hospital at Westmead and the University of Sydney in Australia  argue that physical inactivity is just one marker and that there is substantial evidence that unhealthy diets low in fibre and high in sugar and large portion size are also responsible for obesity and the diseases associated with it.

However, Dr Richard Weiler, a specialist registrar in sport and exercise medicine at Imperial College Healthcare NHS Trust and general practitioner, and colleagues believe that inadequate cardio-respiratory fitness causes disease more than excess body fat, waist size and body mass index.

Weiler and colleagues maintain that "physical inactivity is one of the greatest health threats facing developed nations today" and they are concerned that 95% of the populations in England and the United States do not meet the recommended guidelines of doing 30 minutes moderate to vigorous physical activity on at least five days a week or equivalent.

They say this is alarming given that physical inactivity rather than obesity per se is an actual cause for many illnesses including obesity, heart disease, type 2 diabetes, mental health problems, high blood pressure and dementia.

Spending huge amounts on treating obesity is not the right way forward, they argue. Weight loss drugs and surgery are risky and the long-term benefits are limited and they certainly do not have the associated health benefits linked to physical activity. They conclude that it is time for health policy and healthcare professionals to focus on fighting physical inactivity, a "chronic disease that has an adult population prevalence of 95%."

University of Sydney Professor  Louise Baur and colleagues respond that "on its own, improving physical activity will have little impact on reducing overall levels of already established obesity."

She believes that obese people need access to high quality treatment provided by well-trained professionals to deal with their weight and any linked health problems.

In conclusion, Professor Baur and colleagues advocate tackling obesity with a range of strategies, for example, increasing physical activity, improving diet and lifestyles. They say urban planning should be developed to encourage people to use their car less and cycle more and public transport should be made more accessible and affordable.