How does one "forget/not want to" eat?

Yeah, I don't get it either, but I can imagine how people would do that without having actual experience with it. I have days where I'm not very hungry, and days where I have one meal a day or even nothing, but I don't forget about food or stop wanting to eat it, I just got better at not responding to every single cue and learned to dismiss them sometimes. I also got better at not freaking out when I'm hungry if I need to be hungry for a large evening meal with friends, and my lower hunger days I still have to be conscious about my food because my eating isn't always motivated by hunger, so when I say "I'm not hungry" it rarely translates to "I don't want food". It simply means "consciously making the decision not eat is easier". When I'm playing a very exciting game, I don't exactly forget to eat, I'm just too involved in it and don't want to leave it to get food, it feels like less of a priority at the time, which is weird but I'll take it. I do eventually get up and eat.

Yesterday I ate eggs too many days in a row, and that usually causes me nausea and stomach pain for a few hours. I still managed to want and eat a piece of chocolate cake.

Now, how you go all day without food for a big meal at the end of the day? You just do. First couple of times are hard, but then it gets easier as you familiarize yourself with the feeling of hunger and it doesn't freak your out anymore. In fact if you watch closely, you'll see your hunger goes in up and down waves and you aren't hungry all the time despite what your brain is telling you. In fact after you get used to it most of the time you aren't truly hungry, except for that low level easy to handle feeling of an empty stomach and you're more aware of your brain's tricks making the memory for hungry moments more vivid and stretched out than they really are so you remember being hungry all day. It's not ideal, and I would rather not be hungry, but if the meal is worth some discomfort then it's worth it and I'm not intimidated by the process anymore!

The hunger I have a real issue with is when I have eaten but I'm still very hungry. If the meal isn't doing what it's supposed to be doing (making me less hungry) then I tend to overeat trying to get it to do what it's supposed to do. I can expect a certain delay for satiety to register, but if after that it doesn't happen I tend to overeat. That's why I make sure my meals are satisfying both mentally and physically. In some odd way it's much easier for me to not eat than to eat and not be satisfied.

For me, the reason i got to the highest weight i was, 350 pounds, was because i had untreated binge eating disorder. I would binge all the time. In junior high and highschool, i thought i was fat and people would judge me if i ate so i didnt eat in front of people. By the time i got home, i was starving and would eat basically a huge meal of snacks, then two plate fulls of dinner, lots of dessert, and when everyone went to bed i would sneak food and hide it in my room and eat it. I also drank almost 3/4 a gallon of milk a day, sodas and energy drinks out the wazoo.
But i also knew i was fat and would try dieting, but they would always be crash diets and i eventually ended up in a cycle of i either restrict to the max of under 1000 calories a day or i binge over 10000 calories a day. Im now in therapy and see a psychiatrist. I take a medicine that controls my binges. I can say no to food now and i dont think about it 24/7 like i used to. Apperently with binge eating disorder, you either lack a certain chemical in the brain or have super low levels of it. Which the medicine replaces and balances. Also if im doing something, im the type of person that i cannot stop in the middle and finish it later. I have to finish it now. So i forget to eat meals because im so focused on what im doing. I read all 4 twilight books in 4 days. I didnt sleep. I didnt eat. I didnt shower. I took the book to the bathroom with me. Lol. So basically i ended up fat because of an eating disorder and i forget meals because my medication tells me i dont have to think about food plus everytime i diet i go in a cycle of restriction and bingeing (which im getting help for) plus if im focused on a task food is the last thing on my mind. Keeping busy always helps. I hope this post helps you!