EVERY DAY, more than 12 million youngsters in this country have breakfast at school under a Department of Agriculture program that costs $200 million a year. Federal attention to the importance of the morning meal started in 1967, when the White House Conference on Hunger revealed that many school children were unfed at the beginning of the day. Agriculture Department officials were so concerned about possible malnutrition that they asked several food manufacturers to develop substitutes for traditional breakfast foods - so that schools with limited kitchen facilities could also offer breakfasts. Those corporations came up with "fortified grain-fruit products," more commonly known as "superdoughnuts" - cakes or cookies that take the place of cereal and fruit, but that have just as many vitamins and minerals.

Everything was positively yummy until last year, when the department's dietary experts banned the superdoughnuts on grounds of excessively high sugar and fat content. But, because of an effective lobbying campaign by the food manufacturers, that ban was never enforced. Recently the department again announced its intention to ban the superdoughnuts - and again the corporations have begun to fight. The manufacturers argue that the fortified products need a high sugar and far content to disguise the taste of the extra vitamins and minerals, and that without the superdoughnuts youngsters would go hungry, since many schools are unable to serve anything else. For their part, the department's experts believe the high sugar and fat content of the fortified foods may be harmful to children, regardless of how many vitamins and minerals are added. They also point out that none of the nation's schools serve superdoughnuts every day; most days children eat milk, cereal, juice or fruit and the like> all of which take as little perparation as fortified foods. Officials in the department insist that children will not go hungry if the superdoughnuts are banned; they will simply eat other, more healthful food.

What has happened here is simply that in the 11 years since the White House Conference on Hunger, there has been an enormous increase in our knowledge of what is - and isn't - good for us to eat. For example, there is now a consensus that excessive amounts of sugar and fat are detrimental to health - particularly the health of youngsters. That being so, it strikes us as reasonable for the Agriculture Department to resist spending taxpayers' money on breakfast food with high sugar and fat content, even if that means sending the superdoughnuts back to the drawing board - or the bakery.