The London Olympic Games must promote healthy food to tackle the obesity "crisis" threatening the nation, a new report claims.
The landmark event in 2012 must show the benefits local, seasonal and organic food can have on people's health, the research by the Soil Association, the nef (the new economics foundation) think-tank, and the food and farming alliance Sustain said.
Sponsors Coca-Cola and McDonald's should also serve 75% unprocessed, 50% locally sourced and 30% organic food and drink, the study added.
Soil Association spokesman Peter Melchett said: "If London is going to be the greenest Games ever, they have to tackle the 30% of our personal carbon footprint which comes from food.
"And if the Olympics want to avoid looking silly in the face of the obesity crisis now affecting most of the world, they must promote healthy as well as sustainable food."
The report also claims the Olympics should highlight the relationship between physical fitness and healthy food, which in turn could revolutionise the type of meals on offer at all major events.
A London 2012 spokesman said: "Whilst the report does not take into account the scale and practicalities of Games time catering, and does not cover all of the sustainability areas we will need to address for the Games, we do support the broad principles of local sourcing, minimum packaging, maximum recycling and working with our partners to promote sustainable and varied food during the Games."