Mitch Snyder, 35-year-old radical Christian member of the Community for Creative Non-Violence, completed the fourth day yesterday of his announced total fast to force a Georgetown Roman Catholic Church to give more money to the poor and homeless.

Looking visibly thinner, Snyder said he has received "no signals" yet from Holy Trinity Church, at 3510 O St. NW, on his demand that it divert an unspecified portion of its $400,000 building improvement fund to the poor.

A church spokesman said yesterday there has been no charge in the refusal of the parish council to keep all the money for what it says are repairs and modifications essential for preservation of the aging church.

Snyder lay in a bed yesterday in the living room of the row house at 1345 Euclid St. NW where he and nine other CCNV members live. Sunlight streamed through the windows onto a brightly decorated Christmas tree and green plants scattered throughout the room. Christmas cards were tacked on the wall above a fireplace.

A vaporizer hissed softly in the room.

Though thinner in the face, Snyder appeared energetic. He said he has maintained a total fast-no food and no liquid since Christmas Eve-and will continue to do so until he dies or Holy Trinity "resolves this issue."

"I still have a certain amount of optimism" he said. "They are basically decent human beings at Holy Trinity, and I feel this issue will be resolved . . . At the same time, I am as prepared as I can be to die."

He said he has been in touch with his nearest relatives-his mother and a sister-and while they are "not particularly joyful. . . they respect my decision, my conscience."

Several persons close to Snyder say they believe he is serious about carrying out the fast, possibly to death. Medical authorities say Snyder could live 12 to 20 days without food and water.

Snyder's fast marks an intensification in a long-brewing confrontation between CCNV and Holly Trinity. Almost a year ago, an assistant pastor had suggested that parishioners give to the poor through CCNV, which operates a soup kitchen, emergency shelter and other facilities for homeless "street people."

After a brief alliance, relations soured when CCNV demanded that the church divert to the poor some of its $400,00 building improvement fund, including $50,000 in repairs to the organ. The situation stirred intense debate within the church, but the parish council voted to uphold the full $40,000 fund for church use.

Church leaders say Holy Trinity-which has many prominent and wealthy members-already gives amply to the poor, including an estimated $50,000 in clothing this fall.

Snyder says such efforts are inadequate, "as long as there are people starving and dying out there on the streets." He said his fast is exemplary of such starving, "as will be my death if they choose to let me die."