A good substitution for chips, for me, has been crispy seaweed at Trader Joe's. I'm pretty sure some supermarkets carry it but for sure, amazon has it in their grocery section.
It's just seaweed that's been lightly salted with a little bit of oil. Very crispy, light and crunchy. The seaweed taste - I love that anyway, but could take some getting used to if you're new to it.
There are several variations on the chips idea on the supermarket shelves these days - things baked with lentils, veggie crisps, for example. With a little trial and error, you can find your 'junk food' with the least calories and the most flavor.
If you like to cook, there are ways to cook 'chips' of all kinds (different veggies) in the microwave. Using Google, you can probably find a way that works for you. The microwave can make something very thin very crispy in a relatively short time, if you experiment with various techniques.
Bread? I dunno. High fiber tortillas to make burritos instead of sandwiches? Pasta? Any whole wheat pasta that you find that you like - it's amazing how filling a small portion can be, topped with some sauce and a small amount of cheese (and a meatball or two).