Preheat the oven to 160C and line a 22 cm loaf tin with baking paper.
Combine the arrowroot or tapioca flour, hazelnut or almond meal, chia seeds, baking powder and salt in a large mixing bowl.
In a separate bowl, lightly whisk the eggs and stir in the apple cider vinegar and grated zucchini. Combine the wet and dry ingredients and mix everything together with a spoon to form a thick and slightly wet dough, this is when you add the olives if using. Pour the dough into the loaf tin and sprinkle with the sesame seeds.
Bake for 1 hour, or until golden on top. To test, press down gently on the top of the loaf - if it holds its shape, its ready. To store, cover in plastic cling wrap or keep in an airtight container for up to 5 days.