Scorpio rising body .. someone help me?

I know that scorpio rising body is thin and short but curvy and i'm like that but i can't get fat like i'm thin and it's very hard for me to get fat even a little bit, and i don't understand it because Beyonce has rising scorpio and her body is amazing , also megan fox and zac efron are scorpio risings , i think i have a good body but i just wanted to get fat a little..