Do your toddlers have their own seats? If so, you can order them a child meal.
If they are ticketed as "lap infants" they won't have a proper meal allocated to them (try feeding only apple sauce to a 12 month old...).
Still recommend bringing snacks! (my kids are always hungry just before take off when no food is available!).
Small "surprises" at various points during the flight (not necessarily food) are also good to offer as rewards for good behavior and to keep them occupied.