You may actually want to ask your doctor about this.

It could potentially be a sign of physical or mental illness. Or possibly a side effect of taking certain drugs.

do you mean like you forget it in the fridge? if so, i have a labeled styrofoam token in my fridge i take out when i put food in. i put it somewhere i will likely notice it when i get hungry, for example near other food or on my desk. that way i get reminded to eat that first before it spoils.

Yes, no matter the cause (side effect of a drug, adhd, …) do set reminders or do some other technique to eat enough. I set reminders on some days where i might forget it too.

Yeah like others have said, normal ppl get hungry when they need to eat. Forgetting is not normal.

Make it a habit.

Shop for groceries on the same day every week. Buy the same food, enough for one week. Eat the same thing at the same time every day. Set reminders until the habit sticks.

Food is not reward, food is not entertainment. Just treat it like any other task you need to carry out each day. Make it as efficient and thoughtless as possible.

Your endocrine system should take care of that. If it’s not, and you don’t feel hungry, somethings wrong.