Hmmm, this is a real problem but one that's not easy to avoid.
I've just returned from New York and there was a large lady in one of our traveller seats. It was the breakfast service and you really don't need a lot of space to eat our breakfast as there is no tray.
This lady asked me to ask the gent infront to put his seat forward. I obliged. The man infront then said he would do so if the lady infront of him did the same. Sadly, she was sleeping.
For the main meal service, I always insist that people return their seats upright but for breakfast I won't, as these people have made a concious decision to skip breakfast and maximise their rest.
Sometimes, as much as you want to help, there is nothing you can do.