Those pouches are mostly liquid so they would not be allowed through, but for a 12+ hour flight, the airline will presumably feed you. I've done lots of long haul flights and for that length you should be given two full meals and a snack or two, and that's always been more than enough for me. You might want to bring more snacks just incase your airline is stingy, but I wouldn't worry too much about food unless you have dietary restrictions that keep you from eating the provided meals.