My boyfriend and I were just talking about this! My boyfriend was prescribed Vyvanse for his ADHD, and it absolutely killed his appetite, to the point where he suddenly fainted, and when he woke up he realized his Vyvanse took away so much of his appetite that he hadn't eaten in days. To make things worse, they gave him a pill to boost his appetite and it made him exhausted - like, falling asleep out of nowhere exhausted. He had a ton of other shitty symptoms with it, too (dry mouth, nausea). His sister takes Vyvanse, though, and the pill to help her eat, and she does famously on it. Her and my boyfriend both, on their respective medications, eat more than most people I know.

ADHD medication is very personal and it works differently for everyone, so definitely talk to your doctor about it. They can adjust dosage, prescribe you a pill to help bring your appetite back, or just completely switch your medication like they had to do for my boyfriend. You shoudn't have to force yourself to eat anything, it is definitely possible to be on ADHD meds and have an appetite.