Hi Hadi! You're giving us a great opportunity to discuss the use of adjectives, here! They are so important because they help give more meaning to the noun that they precede. In this case, you also want to convey an image linked to appetite. Both words are synonyms. However they convey slightly different connotations. The main difference between the two is that "insatiable" can also mean "impossible to satisfy". A synonym can be "unquenchable", carrying the same idea of "on-going unsatisfied desire". On the other hand, "voracious" means "devouring great amounts of / being very eager to". Interestingly, to me it sounds like "insatiable interests" may be used more often! Hope this helps! If you wish to discuss expressions and deeper meanings of words that appear to be synonyms, feel free to visit my teaching page and get in touch! Micha.

It's possible to say an "insatiable interest" or a "voracious interest" (not plural "interests") in a singular thing e.g. science. But from your comment to Gary, the more common collocation would be "insatiable/voracious appetite". I agree with Micha's explanation of the distinction in meaning, however both words would be equally suitable if you just wanted to convey the idea of a very strong interest.

Both words are very extreme, and they can have a negative sinful type of connotation, particularly insatiable. To me, neither really go with interests. Do you really mean to be so extreme?