In this realm, most of the ghosts always live in the atmosphere of anxiety, Illusion and fear. Their Desires are never satisfied. The hungry ghosts cannot eat as their throat is as narrow as a pin, but their stomach is as large as a drum. Apart from hungry ghosts, there are also Yaksa, Raksa, Spiritual Ghosts, etc.. Spiritual ghosts are dwelling in the nature, e.g. trees, mountains and seas, and protecting the creatures, while Yaksa and Raksa are Evil, malignant and violent.
If one wants to avoid descending into the Realm of the Hungry Ghost, one has to learn to control one's Desires. One cannot have an insatiable Desire. In general, the Desires of humans are for money, sex, Fame, Food and sleep.
If one Desires Wealth, one should reason that Life only lasts for several decades, and that this Body is illusive and will soon vanish once one dies. One should be satisfied once one has enough money to spend. One should not enslave one's Body and Mind to constantly pursue Wealth causing a disturbance in one's Body and Mind and making one a slave to acquisition. Such a person, when he or she dies, will most likely fall into the Realm of the Hungry Ghost because of insatiable Desire. If we constantly contemplate this, erroneous thoughts in desiring Wealth will slowly disappear.
An insatiable Desire for sex is also one of the greatest Desires of humans. If one wants to avoid it, one should cultivate the Meditation on impurity. Impurity means the impurity of the physical Body. Outwardly, the Body is beautiful. Inside are bones covered with offensive smelling meat. The sensual enjoyments of sight, smell, Sound and taste are only temporary. The beautiful Body is fleeting, like dew, a dream, a bubble or lightning. We must not become attached to such illusive Beauty, for such Attachment is a major obstacle in our cultivation. Everything should be viewed naturally - not because Beauty has moved our hearts. In this way, we will not be greedy towards the temporary enjoyments of sight, smell, Sound, taste, and touch.
Concerning Fame, few people in the World remain unattached to it, especially in the face of the ancient saying, "People strive to prove their worth, and The Buddha strives to prove His honour." The problem concerning Fame is pronounced. Think about this: throughout history, how many people have pursued Fame and fought for it? And how many of them can really be remembered? The World is changing all the time and Sentient beings transmigrate and regenerate.
Life on Earth is even shorter; very soon it will be all over like bubbles and the dream flower. Even the physical Body does not last forever, much less Fame and honour. If one does not exist, where is one's foothold for Fame? So, whether it is slander or praise, we should follow our conscience to uphold our integrity and avoid asking for Fame. Then the Greed for Fame will subside and an honourable name will be formed from generation to generation.
Indulging in the Desire for good Food will become serious. It seems to be a small matter, but the harm it will cause is great. We cannot have unrestricted Desire for good Food because, if we have insatiable appetites and are constantly changing our taste, it will be very easy to commit killing [of an animal). Furthermore, indulging in too much in Food increases the cruel side of our nature and encourages our animalistic sexual Desires. This will become a major obstacle in our cultivation. Therefore, it is better to treat Food lightly and consume only pure Food.
Next, we must consider the fondness for sleep. We have to put a limit here, too. If we are overly desirous of its comfort, it will encourage Laziness and increase drowsiness. The Mind will veer off the righteous Path toward Evil. Isn't this horrible?
Hungry ghosts are hungry all the time, if they find Food and put it into their mouths, it will change into flames, burning their mouths. They are starving, yet they cannot eat. So "hunger" is the major Suffering, and that is why this realm is called the Realm of Hungry Ghosts.