I have also thought about this one. I cannot get away from snap locks bags, but i do re-use them.
I think the best way to reduce waste is to get a dehydrator and do your own meals . I vacuum seal these into portions, but bring them all home and wash and re-use the pouches where i can or put them into the plastic recycling at supermarkets. My waste at the end of a bushwalk would fit into a small snaplock bag, and it will all get sorted, washed out and re-used or taken to a plastic recycling bin.
The main problem is individually wrapped things. Here are some ways i have changed my approach:
I used to use coffee bags, but stopped, partly on account of the individually wrapped bags. I have accepted that decent instant coffee is the compromise.
I used to buy muesli bars, but couldn't justify the individually wrapped bars, even if they are convenient. I spent a long time trying to find a recipe for a bar that would maintain a good shape over a 5 day walk. I slice it up into portions and into one snaplock bag. Recipe below (elsewhere on this forum too).
I used to take the individual Babybel cheese, but now i buy a block of decent parmesan/pecorino and wrap in baking paper and in a snap lock bag. If you place it in the centre of your pack (well insulated) it will survive even a warmish few days.
I use biodegradable floss... (i know this is a very minor component, but still worth mentioning
I reuse small sample toothpaste tubes (also, a minor component) rather than buying new travel sized tubes. I use a syringe to re-fill.
The Best Granola Bars Ever (from The Fitchen)
1 c. rolled oats (1/2 of the oats ground in food processor)
1/4 c. raw pepitas
1/4 c. raw cashew pieces
1/4 c. millet
2 Tbsp. raw sunflower seeds
2 Tbsp. oat groats
5 dried Turkish apricots/figs
2 Tbsp. flax seeds
2 Tbsp. raisins
2 Tbsp. dried, unsweetened cranberries/currants
1/3 c. brown rice syrup
1 Tbsp. peanut butter
1 Tbsp. raw honey
1/2 Tbsp. coconut oil
Preheat oven. Mix all ingredients except apricots, brown rice syrup, peanut butter, coconut oil, and raw honey in a large bowl. Food process apricots until they ball up. Add brown rice syrup, peanut butter, coconut oil, chopped apricots, and honey to a sauce pan. Heat mixture over med/low heat. Add heated wet mix to dry mix, ensure its pretty sticky and not dry and crumbly. Line an 8×8 pan with parchment paper and add granola bar mixture. Flatten with hands or rubber spatula. Bake for 25 minutes. allow to cool before cutting.