Here's the Purtian John Owen on how our tendency is to lose our "appetite" for Christ as we age in the Christian life, as well as him writing on how we should spiritually feast upon Christ. What rich and sobering truths to ponder as we prepare for the Lord's Table each week: 

Feasting upon Christ:

Moreover, be not contented to have right notions of the love of Christ in your minds, unless you can attain a gracious taste of it in your hearts; no more than you would be to see a feast or banquet richly prepared, and partake of nothing of it unto your refreshment. It is of that nature that we may have a spiritual sensation of it in our minds; whence it is compared by the spouse to apples and flagons of wine. We may taste that the Lord is gracious; and if we find not a relish of it in our hearts, we shall not long retain the notion of it in our minds. Christ is the meat, the bread, the food of our souls. Nothing is in him of a higher spiritual nourishment than his love, which we should always desire. In this love is he glorious; for it is such as no creatures, angels or men, could have the least conceptions of, before its manifestation by its effects; and after its manifestation, it is in this world absolutely incomprehensible.

The spiritual appetite:

We hear the word preached as much as ever; but do we do it with the same desire and spiritual relish as before? Some hear to satisfy their convictions, some to please their fancies, and some to judge of the persons by whom it is dispensed. It is but in few that the necessary preparation for the due receiving of it is found. When men grow in age they lose much of their spiritual appetite for food. They must eat still for the maintenance of life; but they do not do it with that desire after it, and that gust in it, as in the days of youth and health. Hence they are apt to think that the meat which they had formally was more savoury than what is now provided for them; though what they now enjoy is much to be preferred before what they then had. The change is in themselves. So we may find not a few professors [TF: i.e., someone who professes faith in Christ], who are ready to think and say that the preaching which they had in former days, and the religious exercises which they were engaged in, were far to be preferred above what they now enjoy. But the change is in themselves; they have lost their spiritual appetite, or their hunger and thirst after the food of their souls.

From The Glory of Christ (Banner of Truth), pp. 338, 450. HT: David Robertson