Evidence-based nutritional guidance and other lifestyle advice are now available in the U.S. government's 2010 Dietary Guidelines for Americans, according to a joint statement from Agriculture Secretary Tom Vilsack and Health and Human Services Secretary Kathleen Sebelius.

Vilsack praised the research that went into the document, saying it was badly needed in the current health climate.

"The 2010 Dietary Guidelines are being released at a time when the majority of adults and one in three children is overweight or obese and this is a crisis that we can no longer ignore," he said, adding that "the bottom line is that most Americans need to trim our waistlines to reduce the risk of developing diet-related chronic disease."

Portion control and nutritional content are at the heart of some of the guide's main recommendations, including the injunction to fill half of one's plate with fruits and vegetables and opt for low-sodium foods whenever possible.

Experts say a healthy diet is an effective defense against numerous types of disease, and can also be more cost-efficient than getting treated once a chronic condition develops.