Not really. In the first two, your "word" is your promise.
Originally Posted by notletrest
In the second, your "words" are what you said, and you eat them because you were wrong.
When you break your word, you have shown a lack of integrity. When you have to eat your words, you are simply mistaken.
I will loan you $10 once I get paid on Friday is a promise. If I don't loan it to you, I've broken my word or gone back on my word.
You will never repay me the $10 you owe me. Then you do, so I have to eat my words.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.