If Democratic presidential candidate Sen. Bernie Sanders has his way on energy policy, most of the country would be "naked, living in a tree," said outspoken Democratic Sen. Joe Manchin of West Virginia on Wednesday.

"Bernie reminds me of my friend Brian Schweitzer. Schweitzer has always said 'unless you're naked living in a tree eating nuts, by God you use energy," said Manchin on Wednesday, referring to the former Democratic governor of Montana. "And I think Bernie might be naked living in the trees."

The West Virginia senator made the remarks to laughter at an energy forum hosted by the oil group American Petroleum Institute about the 2016 elections.

His comments come as the Vermont Democrat is calling for a nationwide ban on fracking ahead of the New York primary. Democrats from fossil-fuel heavy states are backing away from the left-leaning candidate and toward Hillary Clinton, who they see as more centrist.

But Manchin isn't that thrilled with Clinton, either. He said he is supportive of Clinton and has a relationship with her, in which he feels comfortable addressing his concerns with her, but "I don't agree with the things she's saying."

Manchin called Clinton out for comments she made last month at a town hall in Ohio, saying she would put coal companies and coal miners out of work if she becomes president. She later wrote Manchin a letter explaining that she misspoke and said the government needs to do more to support coal workers who are losing their jobs.

Former Louisiana Democratic Sen. Mary Landrieu, who also addressed the forum, said she is endorsing Clinton because her energy policy appears to be more favorable toward fossil energy-producing states.

"I am proudly supporting Sen. Hillary Clinton for president, and believe she is best suited among the candidates on both sides to try to find a middle ground," the former senator said.

She added that Clinton would be more friendly to fossil energy states than the Obama administration has been.

"I think she would be more friendly than what we have currently," Landrieu said. The senator, who lost her last re-election bid in 2014 to GOP challenger Bill Cassidy, is senior policy adviser at the law firm Van Ness Feldman.

Heather Zichal, President Obama's former climate and energy adviser, said she also is backing Clinton, but it would be a struggle for her once she is in the Oval Office to get congressional backing on energy and climate issues.

Zichal said "when," not if, Clinton is elected, there won't be a great "watershed moment" where her goals align with Congress. In the interim, Zichal said Clinton will use presidential authority to move ahead her agenda until a relationship is developed with Congress. Zichal is a fellow at the Washington-based think-tank Center for Strategic and International Studies.