John 6:53 NIV
Jesus said to them, “I tell you the truth, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you.”
Seems biblical to me.
The Biblical explanation to your verse (in the same chapter if you bother to keep reading)...
John 6:58 “This is that bread which came down from heaven: NOT as your fathers did eat manna, and are dead: he that eateth of this bread shall live for ever.”
Jesus wasn’t talking about a physical eating of his “flesh” like their ancestors did with manna (like some of the people initially thought). This “eating” is belief through faith.
Peace.