Obesity in 10- and 11-year-olds in England has risen 30 percent since 2006, part of a far-reaching decline in children's health since the start of the century, said a report published Wednesday.

The study by charity the Food Foundation described the increase in children struggling with their weight as "deeply worrying".

Other findings included a steady fall in the height of five-year-olds since 2013 and a rise in type 2 diabetes among under 25s, up 22 percent in the past five years.

Potential causes included "shocking levels of poverty and deprivation" and the "aggressive promotion of cheap junk food by the food industry", said the report's authors.

The country's recent cost of living crisis has "intensified" the struggle many families face to put healthy, nutritious food on the table, they added.

The decline was "shocking and deeply sad", former government food adviser Henry Dimbleby said in the report.

He urged whichever political party wins the UK general election on July 4 to take "decisive action to make healthy and sustainable food affordable (and) stop the junk food escalation".

One in five children was obese by the age of 10/11 when they left primary school, putting them at greater risk of later developing type 2 diabetes, according to the research.

Despite the publication of 14 government strategies to tackle obesity between 1992 and 2000 "containing 989 policies, no progress has been made".

The report -- A Neglected Generation: reversing the decline in children's health in England -- said the first cases of adolescent type 2 diabetes were diagnosed in 2000, followed by a tripling of type 2 diabetes cases between 2012/13 and 2020/21.

Political leaders had to "reverse the current trajectory", it said.

"Failure to do so will lead to a generation burdened through their lives by diet-related illness and the consequences that brings with it".

Those consequences would include both mental and physical ill health as well as "an overwhelmed health care system that is unable to treat people effectively and economic inactivity that weakens GDP (gross domestic product).

The UK's state-funded National Health Service (NHS) is currently straining under a massive pandemic-related backlog while the economy has seen stagnant growth and productivity.