The US government is mulling alterations to the Food Guide Pyramid on the basis that a large number of Americans do not understand it, and are notably not following its recommendations with regard to serving sizes, according to nutritionist Kristin Marcoe, from the Center for Nutrition Policy and Promotion at the United States Department of Agriculture (USDA).

Federal government has used the Pyramid as a primary tool for promoting healthy eating since 1994, but a recent study by Marcoe pinpointed America's tendency to consume higher than recommended portion sizes as the cause of the growing levels of obesity.

Speaking at the annual meeting of the American Dietetic Association on Monday, Marcoe commented: "The USDA is looking at reassessing the Food Guide Pyramid and portion sizes is one issue we are looking at. We have had some complaints from users of the pyramid that they don't understand our serving sizes."

Her survey of the 2-day food intakes of approximately 16,000 Americans over the age of 2, "found that oftentimes what Americans eat exceeds what a Food Guide Pyramid serving size is", she told Reuters Health.