I need help with food

Hi, this is a really big problem for me right now and I desperately need some advice from some other autistic people because me and my mum have had 3 arguments just today about this and I don't know how I'm supposed to fix it.

Summer is always a hard time for me to eat. The heat messes with my appetite a lot, certain safe foods aren't safe anymore and having the windows open a lot for air means I can't eat off regular ceramic plates and bowls (I end up using disposable cutlery and paper plates, it's a smell thing, the air makes the ceramic dishware smell awful)

This summer however has been particularly rough when it comes to eating. I live with my mum, sister and stepdad. My mum and sister both eat pretty well and my sister is very conscious of what she eats, she's started counting calories and eating lots of salads and such which is great for her. The only problem is, I now feel like I should be doing that. My safe foods are often a lot of premade, prepackaged foods that aren't very good for you if you eat a lot. I try to make sure I eat at least one piece of fruit or veg every day, but some days it's hard.

The last few weeks I can't help but feel self conscious of the fact that most of what I eat is terrible compared to her. She's my twin and she's already skinnier than me (We can generally fit in the same size clothes but side by side it's obvious), and I wish I could stop comparing her to me but I can't. She isn't autistic, so naturally comparing her to me is a self esteem killer but I can't help it.

I've been counting calories and such and being more concerned with what I eat which means I feel less comfortable eating certain foods I know I can eat because of it. For example, usually when I'm out of the house I'll get a McDonald's meal because I can pretty much guarantee it always tastes the same. However, I'm the person in my family who eats their the most so even if that's one of the only things I will eat, I've tried to stop eating there. A lot of the foods I know I will eat feel childish, or I feel like a picky kid when my mum is eating homemade dishes and my sister is eating salad and I'm there with my oven pizza or snack foods instead. I hate that those are the foods I will eat most of the time.

The problem is now that my list of foods to eat gets smaller, and there are days when I don't feel like eating anything on my food list. There are days I barely have the energy to get out of bed, I don't want to have to wash a thousand dishes just to make a meal I don't really want to eat (It's a contamination fear, I have to pre-wash all the pots I'm going to use by hand before I use them). Me and my mum have argued a lot about this recently and I'm at a loss of how to please her. She always ends up so annoyed about it as if I can help it. She's usually so understanding with issues like this but on food she just isn't and I don't know what to do. She keeps saying if I don't eat enough I'll have to go to hospital which is one of my absolute worst fears which definitely doesn't help.

I feel like such a mess and a failure and I can't help it because I don't know what to do. Anyone out there have any advice or anything I can try? I hate that I feel like this. I'm sorry.