This year the former secretary-treasurer of the Service Employees International Union is feasting on nothing but water as he marks the 17th day of his hunger strike to protest Washington’s inaction over immigration reform.

While the rest of the nation is gorging on Thanksgiving meals, the immigration activist and two other fasters will be in a heated tent on the National Mall at the foot of the Capitol.

“We are a little thinner,” said Medina, who has lost 19 pounds. “It’s a good diet.” He said the goal of the fast was to bring attention to the plight of immigrants. “We are trying to connect with people on a human level, not on a policy or political level.”

Gaunt, with a patchy beard and a wooden cross hanging from his neck, Medina says he hopes that his fast will pressure House Republicans, who have held up action on an immigration overhaul.

“We want to see it sooner rather than later because of all the deaths and the deportations,” he said, referring to the roughly 200 people a year who die trying to cross the Sonora Desert along the southwest border with Mexico.

Some high-profile Democrats have dropped by his tent to lend support, including Vice President Joe Biden, Labor Secretary Thomas E. Perez and House Minority Leader Nancy Pelosi of San Francisco, as well as two Republican members of Congress, Jeff Denham and David Valadao, Californians who support an immigration measure.

“It is a tremendous commitment, what they have been through,” Denham said in a telephone interview. “I think it’s going to have an impact with more and more members…. It helps us bring great recognition to the overall issue.”

Denham says he pressed House Republican leaders last week to act more quickly. But prospects for legislative action before the end of the year appear dim.

Medina, 67, says his family is worried about his health.

“It’s normal that people that love you are really worried,” he said.

At night, Medina sleeps in a room of bunk beds with the other fasters at the Washington Seminar Center, a religious retreat on Capitol Hill.

A full-time nurse checks vital signs twice a day for Medina and two other fasters — Dae Joong Yoon, 43, and Christian Avila, 23 — who also stopped eating Nov. 12. The three risk damaging their livers and other organs as the nutrients in their bodies become more depleted.

During his fast, Medina has found that he needs less sleep. “I wake up and start thinking about what more I should be doing. Then I drive my staff crazy,” Medina said. “At 1 o’clock in the morning, every idea I have is brilliant.”

Medina isn’t surprised that some Republicans have dismissed the fast as a publicity stunt. “[They see us as] these ragtag people sitting at the foot of the Capitol reminding them of what they have to do,” he said. “It’s a hard thing for them.”

Others say Medina’s fast is raising public awareness in the tradition of labor leader Cesar Chavez.

“It moves people who have been getting complacent and saying, ‘It is not going to happen and we should move on and focus on some other issues,’” said Miriam Pawel, a former Los Angeles Times editor and the author of a forthcoming biography, “The Crusades of Cesar Chavez.” “It reminds people of the injustices.”

When Biden sat with the fasters Friday, he told them to call him “Joe,” not “Mr. Vice President,” Medina said.

Medina would like to see the White House do more. Congressional action is needed to address the problems of the immigration system, but the Obama administration, he said, could use executive orders to slow the rate of deportations and keep more families together. (Pressed by a protester in San Francisco on Monday, President Obama said that he was doing all he could legally.)

Medina recalls being stunned in 1968 when he heard that Chavez was fasting to draw attention to labor conditions on farms. Medina was 22 and had been helping Chavez by organizing a boycott of table grapes in New York City. He remembers thinking to himself, “Is he going to die? What will happen to us?”

Chavez abstained from food for 25 days until New York Sen. Robert F. Kennedy, who was about to launch his campaign for president, traveled to Delano, Calif., and gave Chavez a piece of bread to break the fast. “It was a big validation of what we were trying to do,” Medina said.

He says that 1968 fast drove him to get more involved in union activity. He devoted his career to encouraging immigrants to join unions, eventually rising to the No. 2 position at SEIU, which represents janitors, security guards and other service workers. He quit that post earlier this year to lead an advocacy program in Washington for immigration reform.

He expresses hope that his fast will spur the same kind of change that Chavez’s inspired in him.

“It’s been 45 years since that fast, and I’ve never been let down by the American people,” Medina said.

brian.bennett@latimes.com