The government's health watchdog has issued guidance to prevent and treat obesity in adults and children.
Diabetes UK worked with the National Institute for Health and Clinical Excellence (NICE) to develop the guidance, which is the first of its kind.
It is estimated that a third of adults and a fifth of children under 15 could be obese by 2010.
The guidance will be sent to NHS professionals, schools, local authorities, employers and town planners.
"Ten years ago Type 2 diabetes in children was unheard of in the UK. Now we have over a thousand cases, which will keep increasing if the obesity trend isn't reversed," said Jemma Edwards, Care Advisor at Diabetes UK.
"We welcome this much-needed guidance. Now it is down to people on the street, teachers, nurses, employers and parents to play their part in shifting attitudes to combat this epidemic.
"Junk food advertising to kids must be banned and a much firmer line needs to be taken to force the food industry to adhere to food labelling guidelines so people know what's in the food they buy.
"Healthy lifestyles must be at the heart of future generations. Otherwise we will see our children growing up suffering from the complications of diabetes like heart disease, blindness and kidney failure."
The new guidelines offer suggestions on cooking, healthy eating, meal planning and food shopping. They also urge health workers to identify children at risk of becoming overweight, such as those whose parents are obese.
Other suggestions include:
- urging families to become more active by reducing the amount of time spent in front of a TV or computer screen;
- urging nurseries to increase active playtime and schools to adopt a healthy lifestyle ethos;
- encouraging children and young people to have regular meals with parents in a pleasant, sociable environment with no distractions.
Public health minister Caroline Flint said: "NICE makes it absolutely clear, the focus of tackling obesity has to be prevention and that drug and surgical treatment should only be considered once diet, exercise and behavioural approaches have been tried and evaluated."