Yes. They have snacks onboard even in Economy. If it's a long haul, you can expect to see the following:
- Cup noodles
- Sandwiches
- Fruit
- Peanuts
- Drinks
- Biscuits / Cookies
You can ask for these at any time, either by pressing the call button, or by going to the galley and asking for it there or just picking it up from the basket.
Seconds of meals should also be possible, if they have spares left over.