I haven't traveled on Duronto but I've experienced in shatabdi that the captains provide food (and sometimes even without demanding) knowing that the consumption will be low. However, the serving would be only part of the full meal say just a few pooris or rice or probably bread sticks (for evening snacks).
In the end all depends on the coach attendent.
P.S>They will sure come for tips so you can ask them before hand and if they deny you can remind them that they have to come back for tips... ;-)