For context, I have 2 roommates, my sister and her boyfriend. Sister and I had not lived together for ~4yrs when we moved in and bf was not supposed to be living with us but he "stayed over" every single night until I got fed up and asked that he start paying rent.

For even further context, I have autism and ARFID. It is very hard for me to make myself eat if it's something I just do not want to eat and that's why, while at work, I will buy myself safe foods to heat up and eat quickly before work. I work graveyard shift and sleep during the day and wake up 3-4hrs before I have to be at work.

My roommates are constantly eating my food while I'm asleep. Doesn't matter if I have opened it already or not and they never ask. I feel bad because I want them to feel comfortable asking if I'll share but I also am fed up as I buy a majority of the groceries in the house and they only put in about $50 a month each toward groceries whereas I spend about $200 a month on them alone. I try to make sure we always have food but it's hard when sister's bf is 6'6 and eats like he's never eaten before in his life.

For even more further context, my sister is extremely hot-headed and I often feel like I'm walking on eggshells around her. I love her, and I enjoy living with her, but I feel like I can't confront her about anything because she becomes hostile any time she feels like I'm criticizing her.

How do I ask them to stop eating my food without causing an argument? Or at least contribute more toward groceries? We all make approximately the same amt of pay per hour, just different shifts.