With the annual college migration about to begin, many teenagers are on the verge of moving out of the family home, headed off to pursue greater knowledge. Their parents imagine that their children will be habitually bent over a textbook, diligently applying themselves to their studies and living a life of well-ordered priorities. I’m about to pop that bubble.

Parents spend 18 years grooming their children for the moment they will leave the nest and make daily decisions on their own, the most basic being what time to go to bed, and what and how often to eat. As for sleep, college students often don’t, which pretty well wraps up that one.

Besides, the diet issue is what concerns us here. Once again parents succumb to fantasy as they envision their children building food pyramids in their heads for each of the three square meals they supposedly eat daily.

As someone who spends massive amounts of time around college students, let me set the record straight. These are fibs parents tell themselves either out of denial, when deep down they know the ugly truth, or because they truly are clueless when it comes to their children.

Most parents would be appalled if they could see what their children eat when they go off to college. Moreover, they would be alarmed by how erratically their children eat and how quickly they abandon any thought of nutrition.

A recent conversation with a college student’s mother reminded me of the parental delusion about children’s healthy lifestyle choices. This well-meaning mother suggested that if her child’s class schedule did not allow for a lunch hour after several back-to-back classes, her daughter would have to pack a sandwich before she left her dorm room in the morning.

I worked very hard to summon a mental picture of a college freshman leaping out of bed at 7:30 a.m., showering, primping, dressing and so forth, rounding up books and papers for multiple classes, and then reaching for the bread and mayo before heading out the door. Hard as I tried, my imagination just wouldn’t cooperate.

There’s a chance that this young woman might be the only extraordinarily responsible and well-organized college freshman on the face of the Earth, but my money says this student will eat a Snickers bar or half a bag of stale Cheetos or nothing at all before she takes time, four hours in advance, to fix a sandwich for lunch.

When students do make it to campus food venues, their choices tend toward high-carb and greasy. If it contains starch or trans fats, college students gobble it up. It is not unusual to follow students through the cafeteria line and see them bypass the fruits, vegetables and unbreaded meat and walk away with a plate of potatoes, pasta and dessert.

In such an environment, the salad bar is a desolate place, when it’s not surrounded by middle-aged people nostalgic for a life without Lipitor.

If we assume that most students never eat three meals a day and many days often eat just once, and we add several meals a week from fast-food restaurants and pizza joints, it’s easy to see where the so-called Freshman 15 comes from. This is the common term for the weight gain that afflicts many first-year college students when they begin making their own menu choices.

As vexing as it may be for parents to learn that the nutrition emphasized at home rarely crosses their children’s minds, this is really a fairly harmless display of independence and even mild rebellion. Given the array of other poor choices students can make, bad nutrition is probably a reasonable tradeoff.

The good news about college students is that their bodies are both durable and resilient. While just watching them eat makes my arteries constrict and my blood sugar soar, they keep plodding along, French fry after French fry, candy bar after candy bar.

It’s just a matter of time, though, until they will start to care about what they eat. It may not be for years, but eventually they will feel compelled to make different food choices. They will remember all the chatter about eating right that they heard at home, and they may even venture over to the salad bar for a change.

Perhaps that is a more realistic vision for parents to hang on to.