I wonder why this is - is it as simple as SEO? (I can't see how unrelated keywords would help with your SEO really, if anything they might hinder it by triggering spam filters)

Another comment here suggests it could be around copyright. Does adding unrelated jargon to the page give you any meaningful extra protection of the mere ingredients list and instructions though? It strikes me adding a life story might protect the life story, but not the actual (seemingly unprotectable) recipe.

Or is there another reason? I'm intrigued as it seems to be a standard playbook, yet one which presumably costs money and time in writing unique content that's relevant enough to avoid users bouncing...