Instant mountain food is difficult to purchase in Sichuan except the instant noodles. Instant noodles are easy to buy almost anywhere. It is the most popular mountain food in China. But when you buy the instant noodles, be aware that most of the noodles are spicy flavored. So if you don’t want to eat the spicy ones pick the non spicy ones. To eat local food is part of your experience doing the hiking in Sichuan. At the hiking destinations, the local food is a combined version of Sichuan style and Tibetan style. Local food are usually a little spicy, but you will probably have already accustomed yourself into it for the first few meals you tried after you arrive in Sichuan. To go with the porters, the dinners served are usually stir fires of vegetable and meat, rice, noodles. For breakfast, tea and local bread or noodles are normally popular. You can buy coffee, sugar, oatmeal, jams in Chengdu and bring them with you.
For drinking water, you had better to use water purifier all the time. The water at the hiking destinations in Sichuan are fine and not polluted. But there are animals at the upstream of the rivers so they are the source of the possible contamination. To go with the porters hot and boiled water is served at the campsite. To boil the water is the popular way to prepare drinking water here. There are no shops along the hiking trail. And at the towns and cities, bottled water for drinking is the only option and do not drink from the tap water directly all the time. In the hotels they usually have a water-cooking bottle which you can use to cook water for drinking.