People who do drugs tend to be skinny because stimulants suppress appetite. But once they stop doing drugs, they tend to gain weight. Plus he is getting regular meals, where before he couldn't really afford much food. So maybe he did gain a little bit of weight.
I thought he was just malnourished, using it only once doesnt make you THAT underweight. Was he shown using drugs before that chapter? Was it even mentioned before?
I'm not sure. I feel like it was implied. That didn't seem like his first time.
It's like he gained weight and got healthier, even though that's not the case. I llike the new style.