A recent study has found that children in the U. S snack almost three times a day and get about 27% of their daily calories from salty, fatty and sugary treats.

Carmen Piernas, a Researcher at the University of North Carolina-Chapel Hill and Co-author of the snacking study said in a telephone interview, "Kids are moving toward a constant eating pattern".

Children of all ages increased their daily energy intake from snacks by 168 calories a day, with a gain of 182 calories in children ages 2 to 6, Piernas said.

While schools depend on competitive foods for revenue, "the data do not show that improving the nutritional quality of competitive food or restricting certain food or beverages hurts school revenue", said the authors, lead by Nicole Larson at the Department of Food Science and Nutrition.

The authors said that the greater availability of unhealthy food options is likely to contribute to increased risk for obesity.

Children have substituted milk, which is rich in calcium and nutrients and necessary for proper growth, with sugar-packed fruit juices and high-calorie sports drinks.

Almost one third of children are now overweight or obese. First lady, Michelle Obama began a campaign on Feb. 9 to increase awareness of the dangers of obesity.