Supplies of fruit, vegetables, fish and meat could not satisfy demand, it said, while two in three London consumers bought or wanted to buy more local food.
This implied good opportunities for producers, according to report representative the South East Food Group.
Report author Bidwells Agribusiness said demand was growing at consumer and buyer levels and demand in London was worth £9.3bn annually.
It advised producers and suppliers to create an "e-marketplace" to improve promotion and links between themselves and buyers and retailers.
"Nearly all food buyers and retailers wanted better links to producers, easier sourcing, less hassle and a one-stop shop. A strong relationship with producers is essential," said Bidwells.
It also recommended up to 20 street markets across Greater London. Bidwells head of food marketing Richard Walters added: "In the recession, people want to support their community by buying local food and sustaining local shops."
- View the report at www.tr.im/foodhub