It's possible to say : "I just want it healthy". The "to be" is implied. This kind of expression is more informal and more common in speech. The meaning may not always be quickly understood, especially if there is no prior context, and so I advise you to retain the "to be" or other infinitive. The construction with "want" here is : Subject + want + object + to + infinitive + rest of sentence The only variation on this construction is to omit the to + infinitive, as I mentioned above. Your two other options of omitting only "to" or using "being" would not be acceptable.