(Reuters) - Health ministers, alarmed at the growing number of obese children, agreed on Thursday to try to reduce children's consumption of junk food and soft drinks by asking member states to restrict advertising and marketing.

The global recommendations on marketing of foods and non-alcoholic beverages to children are guidelines to the 193 member states of the World Health Organization (WHO).

Diets containing large amounts of fat, sugar or salt contribute to chronic diseases such as diabetes, heart disease and cancers, which cause 60 percent of all deaths worldwide, the United Nations agency says.

"Childhood obesity is increasing globally now. The rate of increase in the developing world is greatest because of a rapid change in diet and physical activity patterns," Timothy Armstrong of WHO's department of chronic disease and health promotion told Reuters.

An estimated 42 million children under the age of five are overweight, 35 million of them in developing countries, according to the WHO. Overweight is one category below obese.

"The risks presented by unhealthy diets start in childhood and build up throughout life," the WHO guidelines say.

Armstrong credited the United States with ringing the alarm bell. "The global attention to child obesity has changed significantly, with the new U.S. administration taking it on as a major issue."

U.S. Surgeon-General Regina Benjamin endorsed the plan at the WHO's annual ministerial meeting.