WASHINGTON (Reuters) Children in the United States will soon be drinking flavoured milk with fewer calories and less sugar, according to the Milk Processor Education Program.MilkPEP, which runs the National Milk Mustache “got milk?” advertising campaign, said on Monday that flavoured milk cartons will contain fewer than 150 calories and 22 grams of total sugar on average this school year.Milk provides calcium, vitamin D and potassium that is critical for children’s diet and development but in short supply in young diets, according to the 2010 Dietary Guidelines for Americans.MilkPEP said milk is the number one food source in America for these essential nutrients.Cartons of flavoured milk will carry just 31 more calories than white milk as the result of a five-year process of industry reformulations aiming to “provide nutritious new products with the same great taste kids love,” said MilkPEP.The healthy trend among milk processors will reduce added sugar in fat-free and low-fat chocolate milk by 38 percent.“There are a lot of kids that don’t want to drink plain white milk; they really love drinking flavoured milk and that’s very important for the essential nutrients in milk,” said MilkPEP CEO Vivien Godfrey.“It’s a happy balance between some added sugars but making sure that the kids actually drink the milk as opposed to taking the white milk on the lunch line and not in fact drinking it.”But flavoured milk has been the subject of some debate in the national conversation over child nutrition.Nearly one in three children kids in the country is obese or overweight.