Everything we do to the planet, we do to ourselves. The health of the planet matters because it affects what we eat and whether we can eat in future.
Food supplies could be at risk as a result of a failure to act on "climate breakdown", MPs have warned.
People's health is also at risk from the spread of new diseases and heat stress as the climate warms, with a warning from the MPs that the NHS is not ready for a rise in health problems as a result of environmental damage.
The government should promote healthier and more sustainable diets which benefit the environment and people's health, including a reduction of meat and dairy consumption, a report by the Environmental Audit Committee said.
And people in cities should have better access to health, sustainable food - with planning authorities able to restrict the number of fast food outlets without stringent evidence requirements, it urged.
Climate change is projected to have major impacts on food systems around the world, affecting the UK's ability to deliver healthy, sustainable diets - with agriculture here hit by weather extremes and the spread of livestock diseases.
The government needs to recognise the risks to national food security from importing 40 percent of the UK's food, including fruit and vegetables from countries which are vulnerable to the impacts of climate change.
A dependency on imports, combined with Government "complacency" over the impacts rising temperatures could have on food production, is risking national food security - compounded by Brexit trade uncertainty, the report found.
Committee chairwoman, Labour's Mary Creagh, warned the country faced a "food security crisis" and called on ministers to publish all the information they held on food security and costs in the event of a no-deal Brexit.
The MPs raised concerns over the impact food price increases could have on the UK's poorest people, particularly pensioners and children, and urged the Government to set out how it plans to maintain food security in a changing climate.
Producing more food in the UK could cut the risks associated with depending on imports from a handful of countries, and the MPs said a new national food strategy should support sustainable production of more fruit and veg here.
The Agriculture Bill, which will govern agriculture after the UK quits the EU, should encourage a switch towards more sustainably produced food, including environmentally friendly farming methods to cut greenhouse gases.
Along with damage to agricultural production and provision of nutritious food, rising temperatures could also hit health with direct impacts such as heat-related deaths in heatwaves.
The report raised concerns the NHS and the pharmaceutical industry did not have enough resources to cope with the environmental changes.
Public Health England (PHE) should broaden its focus to include guidance to GPs and the pharmaceutical industry on Lyme disease, malaria, zika and other emerging tropical diseases.
And PHE should advise local government on the impacts of heat stress and protecting vulnerable people, particularly the elderly, those in care homes and those with kidney failure.
There should be more efforts to protect wildlife, increase "green and blue urban infrastructure", such as parks and wetlands in cities, improve air quality, and measures to improve energy and water efficiency in homes, the report said.
Ms Creagh said: "Everything we do to the planet, we do to ourselves. The health of the planet matters because it affects what we eat and whether we can eat in future.
"We are facing a food security crisis, exacerbated by uncertainty over the UK's future trading position with the EU and the rest of the world.
"Ministers must now publish all the information they hold from Operation Yellowhammer on food security and likely costs in the event of a no-deal Brexit."
And she warned: "More people are living in cities at risk from over-heating and water shortages, they're breathing polluted air, eating more fast food and getting less exercise."
She called for "a planetary health champion" to put the agenda of people's and environmental health at the heart of Government.
A government spokesman said: "We recognise the threat climate change poses to many facets of our national life, including our food production and supply, which is why the UK is the first major economy to legislate for net-zero emissions by 2050.
"We already have a highly resilient food supply chain in the UK, and our National Food Strategy review is considering how we can further address the challenges of a changing climate and continue to deliver safe, healthy, affordable food now and for generations to come."
Emily Beament is the PA environment correspondent.