Thought I'd throw these out there!
They are crisps that are about 80 calories a bag. The aren't made with potato but with Cassava which is some Brazilian plant thing which acts as an alternative. They come in Sweet Chilli and Cheese and Onion and they are heaven. Sweeter than normal crisps but so awesome. And much more filling than a bag of wotsits for example!
Apparently they have some sweet potato ones too but I've never seen them. Available in Tescos!!