My wife and I are both using MFP. It would be nice if we could copy from each other's diary that way only one of us would have to log specific food items at a shared meal and the other could change quanties/ items as needed. The "wrench" allows you to remember meals or copy to another date in your diary. It would be nice to have an option to "send breakfast, lunch, dinner, or snacks to a friend."

There is a feature like that in MFP except it works 180 degrees to what you're looking for.
Your friends can Copy FROM your diary, but you can't push it TO them. If they can view your diary they can click that wrench / spanner > copy to today in their own diary
thats for iPhone, iPad and Android apps
website users also have the ability since November 14th 2012. Click quick tools > copy to today when viewing the friends diary containing the item you want to copy.