Important in this context to me would mean: if I don't eat spinach, or if I skip breakfast, I will NOT lose weight on a calorie deficit. Is that what you mean by important what you eat and when you eat, or something else?

You will always lose weight on a deficit but depending on when you eat the amount for a deficit will be different.

Same for the type of food. From my own observation I will gain weight if I eat only a few pretzels daily even if everything else is the same. I assume they cause my digestive system to lose efficiency.

That’s considered a myth that’s been debunked ages ago.

https://www.webmd.com/diet/features/diet-truth-myth-eating-n...

If I come home, work out and then it’s late and I’m hungry,I’ll often just go to bed and not eat. It’s much easier dealing with hunger when you’re sleep than skipping breakfast and then trying to concentrate at work. It’s also, by definition, easier to resist temptation when you’re sleep....