Making pastry is pretty straight forward. e.g, 100 gram of flower, and 50 gram of butter and some salt. Mix together with some water until you get a dough.
I wouldn't exactly be eating them if i was in any sort low calorie diet. (except maybe for a treat)
Using brown flour will be your best option. You could also subtitle butter and use oil/margarine instead.
Either way, loads more healthier then anything bought in the shops