hey guys plz i need help and its being annoying me for the past few months okay

i finish recovering from my eating disorder/anorexia in november, a during that time i was force to be pescetarianism until i was better so on november 10th 2014 i became vegan what i wanted to be for a long time but couldn't coz of my 2 years of that.

for the last 6 months i want to be a high car low fat vegan, but my parents and even my dietician would not alowed me and here are some of my parents reason
1. carb makes you fat
2.sugar makes you fat
3. all those other people that do that must be doing exercise 24/7
4. we by the food wait till you old enough to get your own place
5. it cost lot of money
6. you being brainwashed
7. do what your dietician say she's the expert she study in these for over 12 years

okay 1st, yeah i did gain weight coz i try it for a month before my parents made m stop. i do cardio 5 days a week and weight training 6 days a week, im already vegan why cant i be high carb low fat vegan. even my dietician would allow me to do that. im 16 150cm (short for my age haha-4.9 foot) 55 kg.

so my question is how can i get my parents and my dietician for letting me be a high carb low fat vegan thx you for your time