It is not permissible to join two complete sentences with no conjunction to join them together. "Therefore" is not a conjunction so the sentence is not grammatical.

I ate the whole bowl/bowlful..... therefore..... Therefore (adverb) can be used AS a conjunction (sort of! People argue about this), but the rules are tricky. Semi-Colon and Conjunction Rules If we try to use “therefore” as a conjunction, it means we’re trying to connect two separate sentences or clauses (ok, ok, there IS a relationship. Eat too much > vomit!) Check to make sure they ARE related. “It was a difficult exam. I don’t think I passed.” (tricky exam > worry about failure. Yep! related!)) Try removing the full stop and put “therefore” in between both phrases. “It was a difficult exam therefore I don’t think I passed.” (punctuation needed, but where?) Put commas on either side of “therefore” to use it as an interrupt. “It was a difficult exam, therefore, I don’t think I passed.” (intermediate step to check grammar - we are not leaving it like this! It's incorrect) Remove the interrupting “therefore” to check whether the sentence makes sense on its own. “It was a difficult exam I don’t think I passed.” No, it's a rubbish sentence. It NEEDS punctuation! How about making it 2 separate sentences? Or....... ....... what about a semi-colon? a semi-colon before “therefore” and change it to a 'conjunction'. People argue about whether it's a 'conjunction' here, or still an 'adverb'. Frankly it gives me a headache so I don't worry about it. “It was a difficult exam; therefore, I don’t think I passed.” So, in summary, I think I would try>> I ate the whole bowlful; therefore I'm sick. (semi-colon) I ate the whole bowlful and therefore I'm sick. (conjunction AND / plus adverb therefore) I ate the whole bowlful and, therefore, I'm sick. (interrupter for emphasis. Would work ok as a sentence even if you removed the 'therefore' - but you'd lose the causality/emphasis) I ate the whole bowlful. Therefore I'm sick. (2 sentences) I ate the whole bowlful. Therefore, I'm sick. (comma pause, to allow for emphasis?) Ooh! What a headache!

Collins English dictionary> THEREFORE > 1. adverb 2. sentence connector thus; hence: used to mark an inference on the speaker's part "Those people have their umbrellas up: therefore, it must be raining." (notice the colon not the usual (?) semi-colon) This is just an addition to my previous long-winded, over-wordy, rambling answer. Some authorities define 'therefore' as an adverb AND as a conjunction. Others try using the nicely vague 'sentence connector' definition. Possibly this is because so many use it as a 'conjunction' anyway. ????? "I think, therefore I am!" "I ate the whole bowlful, therefore I'm sick." (the Collins dictionary seems to indicate they would prefer more than just a comma here, but just a comma seems to be rather common usage now. And I admit I like the short, pithy style > I think, therefore I am!")

You could say- "I ate the whole bowl and now I'm sick." Or you could say "Because I ate the whole bowl I'm now sick". The sentence as you wrote it is correct, but not a natural way of speaking for natives.

It's grammatically acceptable, yes. It sounds awkward, but it's not technically incorrect. I would personally be more likely to say: "I ate the whole bowlful and now I'm sick."