Hello,
the Excel search function and Google search differ considerably, and so do the examples that you give.
Excel searches for a substring in a longer string. If you want to find only strings that are words in their own right, then it stands to reason that there will be a space either before or after the word (or both), so you can do two searches, first for " eat" (space, eat), then for "eat " (eat, space). That should find all occurrences of the single word "eat".
Google searches for words by default, so searching for "eat" will not return beat or cheater. When you enter several words into the search engine box, it will combine them with AND and will try to find pages that have all of these words. If you enclose the words in double quotes, the search engine will try to find the exact phrase.
You can also use Excel to search for an exact phrase. Use wild cards before and after, like "*I like to eat*" and Excel will happily return the cells that contain "I like to eat apples" and "this is what I like to eat".