London ? People should get no more than 10 percent of their calories from sugar, experts say in a major new report today on how to stem the global epidemic of obesity-linked diseases.

The study is the most significant in more than a decade on what the world should be doing about its diet. Although concerns about sugar intake are not new, very few experts have recommended a specific limit.

The food industry immediately decried the document, insisting more exercise is the key to ending obesity.

The report was commissioned by two U.N. agencies, the World Health Organization and the Food and Agriculture Organization, and compiled by a panel of 30 international experts.

The experts say heart disease, diabetes and other diseases that can be caused by poor diet and lack of exercise are no longer just the preserve of the Western world.

The report underlines what doctors have been saying for years — that along with regular exercise, a diet low in fatty, sugary and salty food is key to staying healthy.

The experts recommend one hour of daily exercise, double the amount recommended by the U.S. government but the same as that endorsed by other establishments.

And their recommendations on how much fat, grains, protein, salt and fruits and vegetables people should eat also were in line with prevailing opinion.

But when it came to sugar, their advice was some of the boldest yet.

The experts said people should restrict their consumption of added sugar — meaning sugar not naturally present in honey, syrups and fruit juices — to below 10 percent of calories.

In the United States, which leads the world in obesity, the government’s Dietary Guidelines for Americans advise only that sugar should be used in moderation. The Institute of Medicine, part of the U.S. National Academy of Sciences, recommended in September that sugar could make up to 25 percent of calories.

“There are very few international recommendations on sugar. There are countries that are trying to develop recommendations on sugar, but every time they introduce them, the pressure from industry-led groups is very high,” said Derek Yach, chief of non-communicable diseases at the World Health Organization.

The U.S. National Soft Drink Assn. decried a 10 percent limit on sugar.

“A thorough review of scientific literature on the subject of obesity shows there is no association between sugar consumption and obesity,” said Richard Adamson, the association’s vice president of scientific and technical affairs.

“Study after study shows that restricting foods or food ingredients won’t work. In fact, it can create a ‘forbidden fruit syndrome’ that causes individuals to gain weight,” Adamson said. “Together, we need to educate people about consuming all foods and beverages in moderation and getting more active.”