FOOD is always going to be a fundamental human need; but modern technology has played a key part in significantly redefining our relationship with what we eat, and helping to turn it into a lifestyle statement.

"Food posting" - showing off one's next (or most recent) meal on the internet - is a striking new phenomenon, which underlines how narcissistic and fetishistic our privileged society has become about food. The creation of smartphones with decent quality cameras and cheap access to the internet has enabled people not only to take snaps of anything, but to place the images almost instantaneously in the public domain.

In terms of sheer number, photos of food - from humble breakfasts to sumptuous dinners - are abundant. Sites such as Instagram or Snapchat are predicated on offering a platform for this kind of practice. An Instagram user can take a photo of anything, add a comment, and share it with the world.

In 2011, Psychologist Today offered a list of the top ten reasons why people share images of food on the Internet. Essentially they came down to one concept: display. So, for example, some people post photos of their latest culinary "masterpieces". Some want to show off how swanky the restaurant is, or how special the occasion. Others - by posting images of healthy options - want to make a public demonstration of virtue. It is also a way in which people can assert their identity and lifestyle.

In one sense, ostentatiously displaying food is not a recent concept. The magnificent feasts laid on by the likes of Henry VIII were ways of telling the world how important he and others were. Equally, the punishment of a peasant for eating a deer - food reserved exclusively for a lord - was one way in which power was communicated.

The French gastronome Jean Anthelme Brillat-Savarin once said, "Tell me what you eat, and I will tell you what you are." Posting food on the internet is a way of telling others who we think we are, and how we want to be seen. We use the image of a plate of food to shape our own "public" image.

In this sense, posting images of food is one way in which we participate in what philosophers sometimes call "reification". This is, in part, the phenomenon of treating the abstract, the imaginary or conceptual, as if it were concrete. In this particular case, the digital photo (a mere representation) of food is treated as more important than actual food, because it is used to help the individual to shape his or her social image. Instead of valuing the food itself, people who post an image of their next meal on the internet value what their picture tells the world about them.

The Gospels invite us to see food in a quite different way. Jesus was no misery-guts about food. He was accused of gluttony, and of not being holy enough. He knew how to feast, and - as in Jewish culture to the present day - table fellowship was fundamental to negotiating social and religious identity.

Yet, Jesus offers something more. He inaugurates the fundamental Christian icon of holy eating: the eucharistic meal. This meal is the very opposite of solipsistic showing-off. It is always about community. It cannot happen alone. It is about being fed by God rather than projecting a social image. After eating it, we commit ourselves to being sent out by God, to love and serve the world.

The eucharistic feast does point towards something greater than ourselves. Instead of being about constructing a public image, however, it is a ritual that invites people to partake in a community which feasts on God's self-giving. By sharing in this food, we are formed into a community that is not self-centred, but that lives for others.

Food has always been one of the ways in which humans have expressed and defined their identity. Yet the eucharist presents a powerful and key challenge to the narcissistic uses that our culture makes of food. Instead of being about our image, it reminds us that food is fundamentally about blessing, and gift, and relationship. This is the kind of "sharing" our society sorely needs.

The Revd Rachel Mann is Priest-in-Charge of St Nicholas's, Burnage, and Resident Poet and Minor Canon of Manchester Cathedral.