Is it true that Christians eat human flesh?

Hah! This statement is not true.

The only mention in this context is the statement of Jesus spoken to His disciples regarding His own body and blood.

“I am the living bread that came down from heaven. If anyone eats of this bread, he will live forever. This bread is my flesh, which I will give for the life of the world.” Then the Jews began to argue sharply among themselves, “How can this man give us his flesh to eat?” 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. Whoever eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is real food and my blood is real drink. Whoever eats my flesh and drinks my blood remains in me, and I in him.”

[John 6:51-56]

Jesus in the above verses was talking something deeper than mere flesh and blood, he was talking about His suffering, death, life and resurrection through which He was about to pay the price of sins so that putting faith in His sacrifice we could be saved by His grace (and no works attached).

Apart from this, there is no mention of eating human flesh or drinking human blood. Rather, Bible in Old Testament asked to abstain from certain kind of meats and any kind of allowed meat with blood.

My wife Prerna is vegetarian and she has not eaten even any kind of meat in last 7 years of her devoted faith life in following Jesus Christ.