IN THE REAGAN administration's two years, significant changes, as outlined below, have occurred in Department of Agriculture programs. The changes have left some professional consumer advocates and nutritionists complaining that consumers are consistently shorted. In addition to cuts in feeding programs and nutrition education, they claim, the quality, cost and availability of food may be changing for the worse.

USDA officials say the cuts in feeding programs do not affect the "truly needy"; that the proportion of poor being fed by school lunches, for instance, has actually increased. As for public education, say officials, nutrition information generated by the USDA is in the public domain, and the private sector itself could reproduce some of these materials. Concerning changes in labeling and food safety, officials answer that their proposals reflect advances in technology. Last, food availability depends on the farmer, and his needs must be considered along with the consumer's.

Dr. Jean Mayer, nutritionist and president of Tufts University, considers hunger "essentially the only social problem that has been solved," and that by cutting the food program budget, the USDA, pressured by the Office of Management and Budget, revives the problem and reflects the "pessimism' of an administration that believes in "social Darwinism."

Unhappy with USDA policy, many consumer advocates put their hope in Congress, which, they say, has shown a bipartisan lack of enthusiasm for many cuts in food programs. That, says one, "is a hopeful sign."