An inmate at the Bowden Institution has lost 40 pounds since he went on a hunger strike more than 40 days ago, family members say.

Kevin MacKinnon, 47, stopped eating as a protest against involuntary transfers.

In the last year, he's been moved twice already and is set to be moved again to another prison in the province.

His lawyer Janan Jarrah said shipping MacKinnon from one prison to another is bad for his mental health.

"To just move him away from his only source of support and community and family is, I think, an affront to his human rights,” he said.

MacKinnon’s family wants him to stay in Bowden, since they live in the area. They are fighting the upcoming move in court.

Correctional Services Canada did not respond to requests from CBC News for a comment.

MacKinnon’s sister Kelly MacKinnon said the hunger strike is taking a toll.

"It's very concerning. His health is at huge risk. He's been on this hunger strike for more than a month. He's quite frail, he's having difficulties walking he's so weak,” she said. "He's got liver problems as it is."

While MacKinnon is refusing food, he is drinking water.

He was convicted of second-degree murder in 1995 for shooting his roommate.

The Bowden Institution is a medium and minimum security facility just outside Innisfail, about 110 kilometres north of Calgary.