I'm vegetarian, t. Therefore, I prefer to eat healthily, and fruits and vegetables are always my first option. I'm vegetarian. Therefore, I prefer to eat healthily, and fruits and vegetables are always my first option.

Generally, you should not use commas to separate two independent clauses. You need an appropriate choice of punctuation (semi-colon, colon, period) or conjunction (possibly followed by a comma). Be careful with this type of error, which is known as a comma splice.