New survey says supermarkets are showing signs of becoming environmentally friendly but have not yet gone far enough.
Sainsbury's, Waitrose and M&S are named the three most eco-friendly big food chains in the new report by the National Consumer Council with all eight retailers surveyed showing an overall improvement compared to last year.
But none performed well across the board, the survey said.
Tesco and Asda were awarded a C grade - an improvement from their D grade last year - while Morrisons, Somerfield and the Co-Op received D grades.
Asda was singled out for its Smart Price value fish fingers, made from sustainably-sourced Pollock. The NCC also praised Morrisons and Tesco for selling energy efficient light bulbs at low prices, while Asda Co-op and Somerfield had all increased the proportion of in-season vegetables sourced from the UK.
Larry Whitty, Chair of the NCC, said: "NCC's research has spotted important signs of progress right across the market, with all stores now beginning to embrace sustainability.
"But much remains to be done if supermarkets are to become truly green grocers."
The NCC is calling on major supermarkets to bring in a raft of improvements to become more eco-friendly, including sourcing more UK seasonal fruit and vegetables, selling more low-cost energy-saving light bulbs, encouraging shoppers to reuse carrier bags and using more recycled materials in packaging including for wines and spirits.
Asda chief executive Andy Bond claimed the research backed up his group's view that sustainable products did not have to cost the earth.
Bond said he believed prices did not have to rise as a result of adopting more environmentally friendly policies businesses could actually save money by going green and use the savings to lower prices for customers.
This is in sharp contrast to rival Terry Leavy, Tesco chief executive, who was recently reported as claiming that prices rises may be necessary to deliver a "revolution in green consumption."