I'm in somewhat exact situation like you.. except that my dad didnt think a possibility of the financing behind those protein books.
But one thing is that you can do a health check-up and show him what you got. compare your previous checkup results and prove it to him. thats what my dad asked me to ...so far i have not done that haha....
and whenever i see my dad cutting away chicken fats, I told him i am kinda disappointed seeing the fats being trimmed away. but he just repeated : it is for my own good...and repeated to me not to take too much fat.. take more veges, fruits, grains... the usual good for nothing 'low fat high carb diet'.
and i have faced disapproval from other family members and friends. they even called me stubborn (which i hate it very much since they are stubborn abt not changing their diets too)....when in my mind i see them wasting so much $ and time popping in calorie pills...'suffering' from hunger pangs and when i noticed no weight loss in them they told me they maintaining their weights. and sometimes they lose weight only coz they couldnt get used to the foods at their new environments. so i mean they lost some weight due to other factors. their diets are NOT WORKING and they are carb addicted....they do lotsa aerobics....yeah.. and end up i lost more weight than them.... and i hardly even exercise!
but oh well despite my dad's approval, sometimes when he sees me getting a little potatoes he will kinda say 'hey u decided not to lose any more weight?" ...and he's also jealous of my weight loss...coz he said that he forsees I will gain them back during my umemployment period now....
basically....unless ur dad takes actions against ur WOE... i mean you can still continue with your WOE...thats what i am doing. though with occasional naggings....just continue if they are not removing ur protein from the fridge! Or else if you've got a friend who is also low carbing, tell your friend's results to your dad! So far, I dont have any friends who are low-carbing in S'pore.
or find out if any of ur friends are doing high carb, low fat diets but they are stalled...., ask ur dad why their diets fail....