Why are most of the government's executive dining rooms filled with pale males? Because most of Uncle Sam's movers and shakers and moneymakers are white men.

Such are the findings of the House Subcommittee on Employment Opportunities. It recently completed a race, sex census of 45 federal agencies, and gave them failing grades when it comes to providing opportunities for women and minorities.

The subcommittee, headed by Rep. Augustus F. Hawkins (D-Calif.) reports that recent gains by women and minorities in government are good, but not nearly good enough. To find out why it plans a series of hearings -- Tuesday is the first -- to see what government is doing to upgrade women, blacks, Hispanics, Oriental Americans and other minorities.

Top brass from the Equal Employmen t Opportunity Commission, Office of Personnel Management and Office of Management and Budget will be called to explain government hiring, training and promotion policies.

Using data supplied by the agencies the subcommittee says that although the number of women hired has jumped while the number of male employees has dropped, nearly 80 of every 100 workers at Grade 4 and below is female. Women and minorities also hold only a handful of the supergrade ($50,000 per year) jobs in government, according to the numbers.