How I never gain weight

Girls at my school are like : OMG how are you so skinny, what workout do you do?, what's your diet?
Um bitch I'm on the broke diet. I FUCKING HAVE NO MONEY TO WASTE ON FAST FOOD. AND I HAVE TO BIKE 14 KM A DAY TO REACH SCHOOL BECAUSE I CAN'T AFFORD TO WASTE MONEY FOR THE BUS.

I think I had a pizza like 3 years ago.

AND I CAN'T AFFORD TO GAIN WEIGHT BECAUSE MY CLOTHES WILL BECOME TIGHT AND I DON'T HAVE MONEY TO BUY NEW ONE'S