any evidence of that?

Yeah, read any newspaper.

And why are they famished? Could it be because of US sanctions and embargoes?

You can't blame America for every single problem people suffer. Cuba was also embargoed and managed to pull off a medical system with a lower infant mortality rate than the USA, and as far as I know nobody starved there to the degree they did in Venezuela.

USA sanctions means Venezuela can't be a Petrostate, that's it. There's nothing stopping the government from organizing state industries in agriculture and mineral extraction as well as distribution to build a hyper localized economy. Hell, they're supposed to be communists, this is supposed to be the whole thing they're meant to be doing anyway.

The state of Venezuela is mostly the fault of Maduro's failed governance, and some of the responsibility lays also on the heads of Venezuelans. I personally believe to pretend it's all America's fault is to engage in a prejudice of low expectations.