There is no" 我吃過” in Chinese. Actually it is totally same in Chinese, and its just a bit different when we native Mandarin speaker say it. We use "我吃了” when people ask "Have you eaten ~" We use "我吃過了” when people ask " Do you like to have some~ (foods)" Ex: A:你吃了嗎？ B:我吃了。 A:你要吃麵嗎？ B:我吃過了。