A report published jointly by the Royal College of Physicians, the Faculty of Public Health and the Royal College of Paediatrics and Child Health said that, if current trends continue, a third of adults will be obese by 2020.

Party Response: Liberal Democrats

Patsy Calton, Liberal Democrat Health spokesman, said: "The rising tide of obesity is affecting the lives of countless people and costing the NHS billions. Ministers have yet to grasp the scale of the problem, failing to appreciate the damage it is doing to the health of our nation through increased levels of strokes and heart disease.

"Without action to tackle obesity, England could end up as the overweight capital of Europe. More is needed to encourage active lifestyles and promote healthy diets. People need clear information to help them make informed choices.

"When it comes to tackling the issue of obesity, the government is all talk and no action. It is high time Ministers sent a consistent message about the benefit of good diet and exercise."

Forum Response: British Retail Consortium

Richard Ali, director of Food Policy at the BRC, told ePolitix.com : "We welcome the RCP report on obesity. We have long argued that exercise, stress management and diet all contribute to the health of the nation, and that a holistic approach is required.

"Food retailers have long been committed to playing their part in providing a balanced and varied diet for their customers and the BRC's members are at the forefront of providing accurate and clear labelling on food products.

"The challenge for policy makers is to provide the framework within which consumers can be encouraged and supported to choose healthier diets as part of healthier lifestyles.

"We are convinced that government has the major role to play in achieving this cultural shift through developing educational campaigns that encourage consumers to appreciate the components of a healthy diet by providing clear, simple, consistent and scientifically credible messages."

Forum Response: World Cancer Research Fund

A spokesperson for the World Cancer Research Fund said:"World Cancer Research Fund (WCRF UK) welcomes this report and applauds the steps laid out to tackle the growing obesity epidemic in the UK.

"Many people do not realize that obesity increases the risk for many of the most common cancers as well as diabetes and heart disease. It is estimated that in the European Union more than 70,000 new cases of cancer are attributable to overweight each year – and 9,000 of those cases are in the UK.

"Evidence to date has consistently linked overweight and obesity to post-menopausal breast cancer and to cancers of the colon, endometrium, oesophagus and kidney. There are several likely explanations for the observed increases in risk, including the effect of excess body fat on blood levels of hormones.

"A recent survey commissioned by WCRF UK indicated that although many British people are deeply concerned about both obesity and cancer, less than half of them are aware of the link between the two. "

Professor Martin Wiseman, medical and scientific adviser to WCRF UK said:“Obesity and diet-related diseases already rival smoking as one of the major avoidable causes of death and disability. We need to re-double our efforts to find ways to stop and then reverse this trend, and to increase awareness of the obesity-cancer link,”

“There are many factors that have combined to cause the growing obesity problem”

"WCRF UK is especially concerned about ‘portion distortion’ – the rise of ‘big food’, ‘supersizing’ and ‘value marketing’ techniques that have resulted in larger portions; food that we eat but don’t need, or even really want. We are also being less physically active and snacking more.

Andrew Trehearne, the charity’s head of education, said: “When people are served more, they eat more, it’s as simple as that. As a result we’re consuming more unnecessary calories every day and not taking the exercise to burn them off. This is a major problem in the US where obesity levels are extremely worrying, and it’s heading our way.

"The promotion of energy-dense and low-nutrient foods and drinks using highly effective marketing techniques to adults and children alike has confused people about reasonable portion sizes, the charity adds.

"The World Cancer Research Fund Global Network published the results of its pioneering study ‘Food, Nutrition and the Prevention of Cancer: a global perspective’ in 1997. This report reviewed thousands of leading research studies from around the world and led to a set of clear guidelines for members of the public to follow. It remains current and continues be the most authoritative report in its field and has become the standard basis for policy, research and teaching worldwide. A second report will be published in 2006."

Forum Response: Health Development Agency

Professor Mike Kelly, director of evidence and guidance at the HDA says:"As Britain continues to get fatter, there is no doubt of the health risks and financial burden that obesity poses. It is one of the main causes of avoidable ill health in children and adults today, and as we all know, prevention is better than cure.

"Evidence from the HDA on the management of obesity shows the following:Parents can play a vital role in treating their children's obesity by changing the whole family's approach to diet and exercise.

"Schools can prevent obesity by incorporating a number of approaches, including healthy lunch and snack options and lessons on nutrition and the benefits of making healthy decisions in and out of school.

"Low calorie diets work to treat obesity but there is less evidence about maintaining that weight loss

"Obese individuals who have successfully lost weight are prone to relapse however there is some evidence that self-help peer groups with therapist-led booster sessions on weight loss works to maintain a reduced weight, as does daily weight charting on weight loss maintenance."

Forum Response: Canderel

A spokeswoman for Canderel told ePolitix.com: "We welcome the Royal College of Physicians report on obesity. Obesity in the UK is on the rise, and needs to be addressed urgently with cooperation across government, the voluntary and private sectors. A holistic approach to tackling obesity is required, encompassing diet, physical activity and behaviour.