Basically because you could sit and munch your way through several potatoes worth of crisps just as a snack - they are very easy to overconsume so to protect your weight loss they need to be synned. After all you wouldn't sit and eat two baked potatoes but you could easily eat that much in the form of crisps.
I love the lasagne sheets crisps (do a search and you should find a recipe).
These need to be synned too though, for the same reasons mentioned above..must admit though, I've never ever synned mine and haven't found any differences in my weight losses - I guess I'm just naughty
* Par boil the lasagne sheets so that they begin to turn soft * Once they are soft, take them out of the water and cut into triangular, dorito style crisps. * Arrange onto a baking tray sprayed with fry light, and season with whatever you like. I usally do either salt and pepper, or garlic and chilli flakes. * Spray the crisps with fry light and place in the oven. They usually take around 10 minutes, but be careful because once they start to go brown they easily burn.
Not exactly sure how you would syn these, as I never do However, wouldn't reccommend not synning these as this could have a negative effect on you're weight loss. xx