I'm not rich enough for this metabolism

People with fast metabolisms will very much relate to this post. I've always been a skinny person, never been chubby, overweight and certainly not obese. This I have to thank my metabolism for. The blessing and curse at the same time. Before I started working out I was mostly around 55kg. Dropped to 45kg cause I was suck, but after that it's always been up from there. My dietician told me that in order to gain weight, I'm gonna have to eat A LOT. Hungry? EAT! Not hungry? EAT! And I did that, I gained weight, but that was still affordable back then? You see the bigger you get, the more calories your body needs to function throughout the day, so the more you have to eat. The amount I ate back then to get to 60kg and beyond is now the basis amount I have to eat and still be hungry after all that. As of right now, I could probably eat 4 times a day (excluding breakfast) and still not be too full at the end of the day. Meanwhile a friend of mine with a slow metabolism eats once a day, and still manages to gain weight, like how? Life ain't fair and I'm way too poor for this metabolism.