Freeze it in cubes
Freeze food in silicone cubes. Then its already portioned when you pull it from the freezer. When you cook extra food, or open a tin but don't need the whole amount, you can pour it into a silicone freezer cube. Once
Tips for people on the go
I believe almost everything can be frozen for future use. I have a small container in my freezer for the bits of avocado that can spoil if you turn your back on it, another for bananas, kale and so on.