45 For some need to be fed with the milk of the most simple and elementary doctrines, viz., those who are in habit babes and, so to say, new-made, and unable to bear the manly food of the word: nay, if it were presented to them beyond their strength, they would probably be overwhelmed and oppressed, owing to the inability of their mind, as is the case with our material bodies, to digest and appropriate what is offered to it, and so would lose even their original power. Others require the wisdom which is spoken among the perfect, and the higher and more solid food, since their senses have been sufficiently exercised to discern truth and falsehood, and if they were made to drink milk, and fed on the vegetable diet of invalids, they would be annoyed. And with good reason, for they would not be strengthened according to Christ, nor make that laudable increase, which the Word produces in one who is rightly fed, by making him a perfect man, and bringing him to the measure of spiritual stature.
Source: Orations (New Advent)