WCF
I do both long and short haul, but have seldom encountered the problem you describe. As others (Xenia, NGP)say, it is just a matter of organization. Starting from briefing, especially in longhaul, I recommend to eat something before starting the services. They last for hours and you realize you are hungry when it's too late.
Then after services F/As eat in shifts.
In short haul it is even easier. As Xenia says, you can manage to have a semi-proper meal even in a 1 hour flight (and our service is quite elaborate!).
It seems quite easy to me, but...I am the purser. If the pursers in your company don't understand the simple truth that even F/As eat, then you should take Xenia's wise advice: CHANGE!