I like to keep my fibre intake up too. I've only been low-carbing for a week but I've had lentils or some supermarket mixed bean salad every day in order to get some more fibre into my diet. I've found that 100g of either, along with some meat and other veg/salad hasn't given me a spike, I also eat small amounts of almonds, 90% dark chocolate, sun-dried tomatoes and pears, all of which are reasonably high in fibre. Pears have quite a lot of carbs too but they don't seem to give me a spike. Raspberries are high in fibre and not too bad on carbs, as are blackberries. Quorn 'ham' has quite a bit of fibre and is low carb and low calorie.