I was flying from Singapore to New Zealand (11 hours). Jetstar will not feed you without additional charge. This is company policy. They won't even bring you tea or coffee without charging. In addition, economy class is creepily cold. Bring some warm clothes.
In business class meals included in cost of flight ticked. In economy class you must pre-purchase it.
No, there is no regulation that obliges airlines to provide free food during the normal operation of flights.
However, in the EU they do have to provide free "meals and refreshments in a reasonable relation to the waiting time" when a flight is delayed by more than two to four hours (depending on the length of the flight).
The terms and conditions for a Qantas flight I'm on explicitly mentions that JetStar usually doesn't supply food and beverage as an inclusion. This suggests that they aren't merely bluffing about not supplying it:
Jetstar (JQ) & Jetstar Asia (3K) Flights - Onboard Inclusions/Exclusions
Food, beverages and entertainment are not
included in most Jetstar fares.