To continue on with ways to decrease carbohydrates in your baking......try almond meal instead of all-purpose flour.
There is a one to one ratio of almond meal to flour, but almond meal is more dense so the cake won't be as light even with your leavening agent (e.g. baking soda/bi-carb).
Generally cakes with almond meal have an additional egg as well. You may need to play around with recipes until you get it how you like.
Another option is to add just a small amount of corn starch/flour, tapioca, or rice flour, say 1/2 cup, and the rest of the amount in almond meal. This will give a fluffier cake - but will add some carbs back in ( but can be gluten free).
Here's my favourite basic cake recipe, I adjust it based on the season:
2 c almond meal
3 large or 4 small eggs (or 2 duck eggs)
1/3 c melted coconut oil
3 tablespoons fragrant honey
1 teaspoon bicarb/baking soda
Add fruit and/or spice based on the season and what you have on hand, for example:
*Apple/pears with cinnamon
*Vanilla powder with stone fruit
*use hazelnut meal (instead of almond) with chopped chocolate
*Lemon or orange zest with poppy seeds
Mix all ingredients well and pour into a prepared tin, bake in a low oven (165C/320C) for 30 min. Keep an eye on it as anything made with honey will burn easily.
Enjoy - N x