Is it useful to meditate upon hunger?

Absolutely... this is an important topic for new monks and intensive meditators alike. As the Buddha himself said in the Sabbasava Sutta:

“What taints, bhikkhus, should be abandoned by enduring? Here a bhikkhu, reflecting wisely, bears cold and heat, hunger and thirst, and contact with gadflies, mosquitoes, wind, the sun, and creeping things; he endures ill-spoken, unwelcome words and arisen bodily feelings that are painful, racking, sharp, piercing, disagreeable, distressing, and menacing to life. While taints, vexation, and fever might arise in one who does not endure such things, there are no taints, vexation, or fever in one who endures them. These are called the taints that should be abandoned by enduring.

Reflecting wisely means, of course, with sati, hence meditating.

Relevent, I think, is the Mahasi Sayadaw's discussion on self-mortification:

A wrong interpretation as to what constitutes self-mortification is being made by some teachers in contradiction to the teaching of the Buddha.

According to them, earnest, tireless effort required for meditation amounts to self-mortification. This view is diametrically opposed to the exhortation of the Buddha who advised strenuous, unrelenting exertion (labour) even at the sacrifice of life and limb to attain concentration and insight.

"Let only skin, sinew and bone remain. Let the flesh and blood dry up. I will exert incessantly until I achieve the Path and Fruition I work for." Such must be the resolute firmness of determination, counseled the Buddha, with which the goal was to be pursued.

Thus strenuous, relentless efforts in meditation practices for achievement of concentration and Insight should not be misconstrued as a form of self-torture. Leaving aside meditation practices, even keeping of precepts which entails some physical discomfort is not to be regarded as a practice of self-mortification. Young people and young novices suffer from pangs of hunger in the evenings while keeping the eight precepts. But as fasting is done in fulfillment of the Precepts, it does not amount to mortification.

For some people, the precept of abstaining form taking life is a sacrifice on their part; they suffer certain disadvantages as a consequence, but as it constitutes the good deed of keeping the precept, it is not to be viewed, as a form of self-mortification. In Mahādhamma Samādāna Sutta of Mūlapaṇṇāsa, the Buddha explains that such acts of sacrifice at the present time is bound to produce beneficial results in the future. The Buddha said; "In this world, some people abstain from taking life, causing some physical and mental sufferings to themselves. They take up the right view (of not killing) for which they have to suffer physically and mentally. These people, thus voluntarily going through suffering, to keep; the precepts, at the present time, will after passing away, attain the higher abodes of the devas. These ten meritorious deeds are known as good practices, which produce beneficial results in after life through suffering for the present.

Thus any practice which promotes Sīla, Samādhi and Paññā is not profitless, not self-mortification which is not to be indulged in, but beneficial and is in line with the Middle Path which should certainly be followed. It should be definitely noted that only that practice which does not develop Sīla, Samādha and Paññā but results merely in physical suffering constitutes self-mortification.

(from Dhammacakkappavattana Sutta)

As for a means to practice, it does depend on whether you are practicing samatha or vipassana. Practicing samatha, you would bear with it by ignoring it in favour of the main object of focus, e.g. the breath. Practicing vipassana, you would focus on the hunger as physical and mental aspects of experience, perhaps noting it as "hunger, hunger" or "feeling, feeling", as well as any associated mental and physical phenomena that arise surrounding the hunger.

Hunger, being an existential phenomenon, would not make a proper object of samatha meditation.