It starts with a baby, as is the way with human life. He’s a breastfed little nursling, which means there is no lunch you need to pack. How convenient and unburdensome. You are free to saunter over the hot sand with only the umbrella and the shade tent and the foldable chairs and the tote bag full of towels and the nappy bag that has clean nappies in it, of course, and also a dirty nappy already wadded up damply in a plastic bag and wipes and a changing mat and two sets of clothes with all their many baffling zips and snaps and also the Special Blanket and the dummy and the sunglasses and the sunhat that makes your baby look like a miniature yachtsman. And don’t forget the baby himself, as fat and pink and snuffling as a hot, sandy piglet … Plan to spend the day admonishing your husband because the baby is getting sun in his eyes/sun on his face/some sort of heat rash on his baby shoulders. The baby is eating a cigarette butt/a seashell/a handful of sand. The baby is hot/hungry/tired/choking on the piece of string attached to someone’s abandoned and deflating balloon. Older parents smile at you in a way that, years later, you will understand to mean: “Go home and lie beneath the fan. There will be many better summers to bring this child to the beach.” Instead, you wedge yourself into a small patch of shade to nurse the baby down for his nap while you daydream about someone coming by with so much iced coffee they’ve had to carry it to you in a bucket. The baby seems incorrectly certain that pressing the full length of his body against you will be cooling. You push the sweaty wisp of hair off his forehead and he reaches up a fat little hand to push the sweaty hair off your forehead. This is his favourite joke, and when he smiles at you from beneath your boob – you can actually see his eye crinkle up – your heart swells so burstingly that it presses against your ribs like an affliction. The filling melts out of the cookies, but the kids don’t care. They lick their fingers and tip their rosy faces to the sun The years that come next are, if you’re honest, a bit of a blur. “What did we feed the kids on the beach when they were toddlers?” you ask your husband now, and he wrinkles his brow in a kind of performative remembering way and says, “Crackers?”, which is really all you need to know about who was in charge of lunch on the beach. In your memory, the children are like baby birds, heads tipped back, beaks open, clamouring for their lunch – even though the photos show only cheerful little tots wrapped in colourful towels and drinking from sippy cups in a perfectly reasonable way. Probably the lunch you bring involves many lidded containers of unchokeable items: halved grapes, tiny cubes of cheese, cooked apple slices, and those biscuits that dissolve into a safe paste on contact with a child’s tongue. Bananas, maybe? Avocado, browning in the heat? Of course, some days you barely make it to the beach because your tiny shoeless daughter squats right down in a patch of sand in the parking lot, and you cannot convince her that a better, broader expanse awaits just down the path. You carry her, weeping, to the shore and offer her a consoling juice box. When she pokes in the straw, a stream of pink juice geysers up out of it into her own face and she laughs as long and hiccupingly as an actual maniac. On the measuring wall at home, the marks creep upwards as the children grow – chubby in their swimsuits one summer, stretched long and lean the next – and their taste in lunch changes like the weather. They eat sandwiches now, like regular beachgoers, but they’re not so sure about condiments. One year one of them wants dry turkey on dry bread, and you cringe to make it, reminding yourself that this is a victimless crime (lunch preferences, like hairstyles, clothing, and gender, are, you understand, benign forms of self-expression). Another year this same child stuffs a handful of sour cream and onion potato chips into peanut butter and jelly and offers you a bite; it is a revelation. They eat ham with yellow mustard one summer; with Dijon the next. One child picks out from his sandwich anything he identifies as salad, which includes lettuce, tomatoes, pickles and peppers. The other child seems to think of the beach itself as a crucial component of her lunch experience: she rolls up from the water like a sea lion breaded in sand, and everyone screams when she tries to stick a sandy hand in the chip bag; when she chews, you can hear the grains beneath her teeth and it gives you goosebumps. Both children are afraid of the insects that bite, and the seagulls and dogs, which loiter around eyeballing everybody’s cherries and snacks. The cream filling melts out of the cookies, but the kids don’t care. They lick their fingers and tip their rosy faces up to the sun, as spangled with sand as sugared pastry. “Just this, please,” you think – to yourself, because you know better than to share aloud your deranged thoughts about loss looming around every corner. “Only this.” As the years pass, you grow less worried about the children drowning – they can actually swim. Now the children have moods and spots and, in a certain slant of light, the smudge of a moustache. They do all the fun beach things now: boogie-boarding and magazine reading and shell collecting and eavesdropping. Lunch improves. Some days you split open crusty bread, brush it with olive oil, and fill it with mozzarella, tomatoes, and basil (well, hold the tomatoes for one kid). Other days you mix mayonnaise into tuna, add pickled peppers, celery and dill, and then fill three of the four sandwiches because the fourth person is a vegetarian who’s going to go with the mozzarella again, if there’s any left. Not only do these galumphing children no longer need to be carried, but they can actually carry things. It’s such a delightfully astonishing flip-flop that you could shout out in joy. One day they’ll be carrying you. Hoisting your old-lady self on to their backs to schlep you across the hot sand! OK, scratch that thought because it’s creepy and awkward. Now you lie on your towel on the beach and admire these capable, conversational, funny people. You think they’re fully grown, but you’re wrong. You don’t understand what’s still to come. That they will yet grow up and away. That they will become true adults, with homes and lives of their own but, by some special kind of magic, they will still join you here, at the beach, for one week every summer. And you’ll say to them, in the beach-town market: “What do you think you’ll want in your sandwiches?” And you will buy them every last thing – the fancy soft cheese and the pesto and the Italian cold cuts – because, despite the fact of your nipples pointing down towards Australia and your face as crumpled as a paper napkin, you are the luckiest person in the entire world. Because tomorrow you will tear off four pieces of aluminium foil while these beloved children sleep late. And you will make their sandwiches, pack up the lunch, and count your blessings, which are too many to count. Sandwich by Catherine Newman is published by Doubleday. To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.