This is completely false. While sperm does contain roughly 5 grams of protein per gloob, a man can replenish that amount be eating a whole 2 chicken nuggets. Frequent masturbation is not going to malnourish anyone who has access to McDonald's quality food or higher.

Masturbation is an important piece of variety in the sex life my boyfriend and I have. I think how you view or use masturbation can be harmful in some cases, but the act itself is not intrinsically harmful.