The government needs to tackle the UK's "failing food system" by linking its policies on health, environment and education, a committee of MPs has said.
The Environmental Audit Committee said a focus on sustainable intensification - or increasing food yields - risked "damaging the environment and society".
It called for gardening and cooking to be part of school curriculums, and for stricter junk food advertising limits.
Defra said it was trying to boost food production at less environmental cost.
"We spend £400m a year on agriculture and food research, we're close to publishing the ambitious Green Food Project to make the whole food chain as sustainable as possible," a spokeswoman said.
"We're also pushing hard for food security to be high on the agenda at Rio +20 [UN sustainable development summit in Brazil] next month."
The department's Green Food Project is considering how the goals of improving the environment and increasing food production can be reconciled.
Unifying policy areas
In its Sustainable Food report, the committee said the government should use the project to develop a "broader food strategy that takes into account the health, environmental, social and economic consequences of the way that the food we eat is produced, sold and disposed of".
It pointed to increased pressure on the global food system from growing populations and climate change and on the NHS from increasing obesity.
Committee chairwoman Joan Walley said: "Our food system is failing. Obesity and diet related illness is on the increase, fewer young people are being taught how to cook or grow food, and advertisers are targeting kids with junk food ads on the internet.
"At the same time the world faces growing fears about food security as the global population increases, more people eat meat and dairy, and the climate destabilises as a result of forest destruction and fossil fuel use."
She said state intervention was needed "to tackle obesity and fix our food system".
"In many cases, reducing environmental impacts and getting people to eat more healthily can be achieved in tandem."
"The government does not yet have a strategy that unifies policy areas that impact on food production, supply and demand in a way that drives the system as a whole towards greater sustainability," the MPs said in their report.
"Such a strategy should explicitly shape the way policy is to be coordinated across departments to provide a sustainable food system," the report said.
"It must also provide an impetus to shift food policy to deliver a more equitable food system so that healthy and sustainable food is available to all."
The Environmental Audit Committee said that:
New national planning policy guidelines should be introduced to ensure that communities had access to healthy food and land to grow their own produce
- Government Buying Standards - that ensure food bought for some parts of the public sector meets certain environmental or welfare levels - should be raised to reflect best practices and extended to cover hospitals, prisons and schools.
- The government should consider introducing simple and consistent labelling on food sustainability - including recycling and nutritional values - "perhaps through a weighting system to produce an overall score".
- The government should also amend the Office of Fair Trading (OFT) remit to take account of sustainable development while protecting competition.
Food production research
The MPs said food systems were "more likely to be sustainable if food reflects value or cost of the environmental impacts of producing it".
But they said Britain did not have a basic science base to deliver more sustainable food production practices and the government needed to "develop incentives" for universities, colleges and Research Councils to train more agricultural and food scientists.
The committee said an independent body should be established to research and report on the potential impact of GM crops on the environment, farming and global food system.
"Until there is clear public acceptance of GM and it is proven to be beneficial, the government should not license its commercial use in the UK nor promote its use overseas," Ms Walley said.
The committee said food waste remained "the largest single issue across the whole supply chain".
"The government must ensure that there is sufficient funding available for all councils to be able to make sufficiently regular and separated food collections, to help develop a healthy anaerobic digestion sector," it said.
The MPs said the government must review its food policy in light of the Rio+20 Earth Summit and ensure Britain's food policy "is consistent with the global aspirations for delivering a sustainable food system".