"It's a terrible stress condition that affects me having an appetite and I'm sorry this is the way I am. Basically I have an eating disorder.
"I'm sorry, sometimes I really wish I did look better, or I eat more like y'all say, this life doesn't come with much stability.
"If you don't believe me ask my brother he was there when I was 19 [and] diagnosed. It's a stress eating disorder, I'm sorry I didn't choose this."
Carter, the brother of former Backstreet Boy Nick Carter, again dispelled rumours that his figure is due to drug use.
"No I don't do drugs, yes I feel pain, I haven't stopped working since I was 7 years old. 22 years later and I still won't give up.
"Any of my fans who I let down or made them embarrassed to be my fans anymore, I'm so sorry. I will never stop trying to win your hearts back."
Carter released an EP, LØVË, on February 10.