The healthy eating drive is at risk of failing because the public is getting contradictory messages, a leading UK food expert says.
People are buying less fruit and vegetables
Professor Tim Lang, of the Chartered Institute of Environmental Health, will make the warning to delegates at the body's annual conference.
He will say too many government departments are involved in policy and a single coordination body is needed.
The government said departments already liaised over policy.
The speech by the City University food policy professor comes after government figures showed people were still not eating enough fruit and vegetables.
The latest data from the Department for Environment, Food and Rural Affairs showed that sales had fallen by 1.6% in the last year, meaning people ate 3.7 portions a day on average - well short of the "five-a-day" target.
Professor Lang, the institute's vice president, is expected to say the government should create a food policy council to integrate different government bodies responsible for food education.
"We need one body that can link all aspects of food - whether environment, industry or health.
"Without such a council people simply get contradictory messages and initiatives for healthy eating fail to deliver."
In recent months the public has been told to eat more oil fish because it reduces the risk of heart attack, while at the same time a different department warns fish stocks are low.
The CIEH has also pointed out a contradiction between the Department for Culture, Media and Sport, which protects advertisers' interests, and November's Public Health White Paper which floated the idea of restrictions on the advertising of unhealthy products.
And while school curriculums teach the virtues of healthy eating, it took a campaign by TV chef Jamie Oliver to highlight the need for better school meals, it was claimed.
The institute is also expected to urge the government to broaden the audience it targets.
Policy officer Jenny Morris said: "While at lot of focus has been placed on the school kitchen, if the message is not backed up by a healthy, balanced diet at home, providing two-thirds of a child's dietary requirements, we will not win the battle against dietary related ill-health."
The institute also recommends using healthy food advertising and food labelling to encourage better diets.
But the Department of Health said departments already talked to each other over policy and pointed out there was the Food Standards Agency to act as a watchdog.
A spokeswoman added November's Public Health White Paper contained many of the recommendations the institute were making.