(AP) -- British health officials say the country needs to slash 5 billion calories from its collective daily diet to slow the obesity epidemic.

In a report issued Thursday, the department of health said most adults in the nation of about 60 million people are already eating far more than they need. The average Briton eats about 10 percent more calories than necessary, the report said.

The U.K. has one of Europe's fattest populations: more than 60 percent of adults and one third of children aged 10-11 are overweight or obese. The new report aims to change diet and exercise habits enough so that the number of heavy Britons begins to fall by 2020.

Britain's chief medical officer, Sally Davies, said people need to be more honest with themselves about just how much food they're eating every day. "We are still too heavy as a nation," she said at a press conference. "Not enough of us are getting it right."

Obesity raises the risk of health problems including heart disease, diabetes, and cancer. Experts said treating fat patients costs the national health service 5.1 billion pounds (US$8 billion) every year.

Health Minister Andrew Lansley said Britain will continue working with the food and beverage industry in a deal to reduce the amount of salt and fat from their products and to post calorie content where possible. The deal was previously slammed by health charities and leading medical organizations who argued the food and drink industry were dictating government policies.

Lansley said the government would consider whether a 'fat tax' could help, but said he would prefer a voluntary and cooperative approach.

The government will also introduce various initiatives to encourage people to exercise, including several linked to the London Olympics next year.

Though London 2012 officials promised they would get 2 million more people exercising by the time the Olympic torch is lit, that goal looks increasingly unlikely. Only about five percent of Britons currently meet the recommended guidelines to get 150 minutes of physical exercise every week.

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