Breakdown of Моя диета намного вреднее, чем твоя.
мой
my (мой, моя, моё) / mine
твой
your [informal] (твой, твоя, твоё)
диета
diet
чем
than / the (in comparisons)
Questions & Answers about Моя диета намного вреднее, чем твоя.
How do you form the comparative word вреднее?
It comes from the adjective вредный (harmful/unhealthy). To make the comparative form for most regular adjectives, you simply drop the standard ending (-ый) and add -ее.
Could I say более вредная instead of вреднее?
Yes, you can use более (more) plus the standard adjective (более вредная). However, the short -ее form (вреднее) is much more common in everyday speech. Notice that вреднее is fixed and never changes its ending, while более вредная has to match the feminine noun диета.
How does намного work in this sentence?
Намного means 'by a lot' or 'much'. In Russian, it's the standard word used right before a comparative adjective (like вреднее) to emphasize the difference, exactly like saying 'much unhealthier' in English.
Why does the sentence end with твоя instead of твой?
Because it refers back to диета (diet), which is a feminine noun. Even though the word диета isn't repeated at the end of the sentence, the possessive pronoun still has to match its feminine gender.