The report from the Royal College of Physicians (RCP) finds that too little is being done for adults who are severely overweight in Britain.
National Health Services are "extremely patchy", it says, even though a quarter of all adults are obese and it is estimated that by 2050 most of the population will be.
Professor John Wass, chair of the working party that produced the report, says there is a real need for leadership.
Wass said Britain could learn from the US, where Michael Bloomberg, mayor of New York, and US first lady Michelle Obama have been leading a successful fight against obesity.
"I think we could have a senior figure in London, rather like the mayor of New York, who has led on having smaller measures of Coca-Cola in cups and other things. Michelle Obama has had a huge effect on obesity and getting things labelled," Wass was quoted as saying by the Guardian.
"Let us say