思ったよりも食べれなかったって英語でなんて言うの？

"My eyes were bigger than my stomach." Is an expression people use to say I wanted a large amount of food, but I couldn't eat everything because I became full. It means the same as "I thought I could eat more but I became full!" Which just means you thought you could eat a lot of food, but your stomach became full and you could no longer eat.

If your eyes are bigger than your stomach, then it means that you want to eat, or try to eat, more than you can eat. For example, if you are eating a buffet meal and leave a lot of food, than your eyes were bigger than your stomach.

When you want to explain that you went fruit picking, ate and got full; then you can say: -I thought I'd be able to eat more than I thought I would eat -When I went fruit picking the other day; I thought I'd eat a lot but I got full quickly. -My eyes were bigger than my stomach.

Express how you feel and why.

To express that you were not able to eat as much as you had wanted to you may state that your eyes deceived you. You may also say that you became full very fast. You may also make use of a commonly used expression in English that states 'My eyes were bigger than my stomach.' This is a metaphor expressing that you ate less than you thought you could.

You could simply say 'I couldn't eat as much as I thought I would be able to.' An English idiomatic phrase that you say when you take more food than you can eat is "My eyes are bigger than my stomach." For example you could say "I got too much food from the buffet. My eyes are bigger than my stomach"