The Government's plan to tackle childhood obesity is "severely limited", experts have said.
Medical and public health experts "had hoped for much more", experts wrote in The British Medical Journal (The BMJ).
The childhood obesity plan, released last summer, drew much criticism from health bodies for omitting new curbs on junk food advertising.
The document had an emphasis on greater physical activity in schools and a voluntary scheme for the food industry to reformulate popular children's products to reduce sugar content.
Also central to the document is the Government's sugar tax on soft drinks.
The draft version of the document was 50 pages long but when it was published it was just 10 pages, wrote Professor Mark Hanson from the British Heart Foundation and the University of Southampton, Professor Neena Modi, president of the Royal College of Paediatrics and Child Health and Dr Edward Mullins, a trainee in obstetrics and gynaecology at Queen Charlotte's and Chelsea Hospital.
They said that "strong actions were conspicuous by their absence" and called the action plan "severely limited".
They added that the emphasis on personal choices and voluntary measures by the food industry were "especially disappointing".
"The concept that obesity prevention is predominantly a matter of personal or parental responsibility has been particularly unhelpful," they wrote.
"Infants and young children are wholly vulnerable to the actions of adults and to the broader societal factors that create an obesogenic environment, including the marketing practices of industry.
"For older children and young people, and their parents, a sole focus on personal responsibility is likely to result in guilt, resistance, denial, and perpetuation of the problem.
"Voluntary actions, ranging from people trying to lose weight to industry developing healthier products, have so far been ineffective in halting the rise in obesity, so the Government's emphasis on personal choices and voluntary measures by industry is especially disappointing."
The authors added: "We do not know why the UK Government reneged on delivering the promised and much-needed strategy, but we do know that the value of investing in long term population health is often compromised by the short term focus of politics."
Caroline Moye, head of World Cancer Research Fund, said: "Theresa May and her government missed a key opportunity to really help reduce the burden obesity is having on our children's health.
"Being overweight or obese increases the risk of a number of different conditions including 11 common cancers."
Public Health Minister Nicola Blackwood said: "No other country in the world has set out such ambitious plans and six months in we are making significant progress, with many industry leaders already taking action to cut sugar in their products."
Duncan Selbie, PHE chief executive, said: "The Government's childhood obesity plan is a good start on the journey to reverse child obesity. It is quintessentially British to complain about what it does not include rather than focus on the significant action being taken.
"Our evidence review called for voluntary sugar reformulation, to repeat the success of the world leading achievements on salt reduction, and much more will be done through the nutrient profiling model and the sugar levy. Let's implement the plan and start making a difference."