A universal system of food labelling which takes into account everything from nutritional information to the product's impact on the environment should be established to guide consumers, according to a food policy analyst.

Tim Lang, of City University, London, said a set of "omni standards" for labels could overcome public confusion over food. The labels could provide information about such things as food miles – the distance an item has covered to reach the shops – and the amount of water used in its production, as well as health information on fat content and nutritional benefits.

It would help to overcome confusing recommendations to the public, such as the health advice to eat more fish, which conflicts with environmental concerns about declining stocks because of overfishing, Professor Lang told the British Association's science festival at Liverpool University yesterday.

"Whilst governments continue to let the market take its course, ill-informed consumer choices are contributing to massive crises in human health, food security and environmental degradation," he said.

"Evidence from water use alone suggests that we need to think more about 'hidden' impacts. Each bean from Kenya has four litres of potable water embedded – this from a water-stressed country."

A new "Good Food System" could stop the current "cacophony" of different conflicting pieces of information from different groups, he added. For instance labels could include a "rough guide" on packaging – perhaps with a graphic displaying a score out of 10 for each of a series of criteria – with links to more detailed information online.

A new food policy agenda should not be focused solely on producing enough food, but should take in new issues including energy, water, climate change, biodiversity, labour issues, health care, and changes in diet, population and where people live, he added.

"We are tip-toeing into a major crisis into the next 20 years unless we turn it in a different direction. The old order is no longer with us," Professor Lang said.

Cheap food was not necessarily good food, and prices had been too low in recent years, he said. "There needs to be a switch from value for money in consumer culture to values for money. Consumer culture is going to have to change."