For reasons I confess I don’t quite understand, zombies are in these days. They populate blockbuster movies, TV shows, and even commercials. There are the classic, grisly, menacing variety, and even some new-age variants that seem almost cuddly, in a creepy sort of way.

But whatever explains the fascination with zombies, they seem to belong to that same taxonomic category of interest as purple cows of silly poem fame: People may enjoy seeing them, but no one wants to be one.

But we are increasingly at risk of exactly that. And far worse — we are at risk of imposing a long span of zombie years on our children. I mean this in the most literal sense.

Zombies are, insofar as I understand their biological classification, undead. They aren’t entirely dead, but they certainly aren’t fully alive either. That sounds a lot like life with a serious chronic disease. When one’s life no longer involves pleasure or the pursuit of interests, it is something of a half-life. When schedules are occupied by medicines, procedures, and doctor visits, it is something other than really living. And when we can’t remember the names of our own children, we are no longer entirely here.

These are, in a heart-wrenchingly real way for anyone affected and everyone who loves him or her, years of only partial living. These are zombie years, and there is nothing cute nor entertaining about them. They are a black void where life sucked out of our years goes to whither and die.

I suspect everyone has heard the assertion that children growing up today may be the first generation ever with a projected lifespan shorter than their parents due to the impact of epidemic childhood obesity and related chronic disease. To the best of my knowledge, I was among the first to refer to the relevant study, by Olshansky and colleagues, and make just this statement in just this way. I have seen a number of quotes that refer back to me as the source, rightly or wrongly, since the original research was not mine.

The assertion might be true; we really don’t know yet. A recent study supports this grim prediction by indicating that obesity is, indeed, killing more of us prematurely than we ever realized, and killing ever more of us the more recently we were born. So perhaps our children will live less long than we do because of diseases we have the capacity to prevent virtually all of the time.

But modern medicine is remarkably good at keeping us alive. If you’ve ever been to an ICU, you’ve seen the full prowess of modern medical technology brought to bear on the issue of survival. But I trust you noticed, whether or not it registered, that the full resources of the ICU — rather like all the king’s horses and all the king’s men — were doing nothing to put true vitality back together again. The resources of modern medicine are impressively good at treating certain diseases and traumas, and forestalling death. But they can’t build health, and rarely restore true vitality.

The result of an ever-increasing global burden of almost entirely preventable chronic disease, combined with increasing life expectancy in spite of it all (so far, at least), is a growing gap between total years lived and years lived well. The former is known as our life span; the latter is our health span. The bigger the gap between years lived well and years lived, the greater the portion of our lives spent only partially living them. A recent report by the Institute of Medicine indicates that the gap between life span and health span is particularly great in the United States, and growing.

So maybe modern technologies will prevent our children from dying younger than we do on average. We cannot yet predict with confidence the life expectancy of the next generation. But as ever more chronic disease begins at ever younger age, we can predict with absolute certainly that our children will be losing even more life from years than we are, and we aren’t doing very well. Our children will be living a growing number of zombie years.

Health care reform will do nothing to fix this, except maybe pay the bills. Modern medical technologies will not fix it. But we can fix it.

As noted, the chronic diseases that stalk us and our children alike and siphon away life from years even when not doing the same to years from life are almost entirely preventable. This is incontrovertibly established in a consistent aggregation of peer-reviewed research spanning decades. We can disease-proof ourselves, and our children, with an application of lifestyle as medicine.

But while we have long known what the medicine is, few know how to make it go down. That can change. Those of us who do know how can share our skill set. We can pay it forward. And every adult who learns the skill power on which healthy living depends can then do the same; each of us can pay it forward to the children we love.

Zombies may make for good entertainment. But the prospect of becoming one makes for a very bleak future. The prospect of bequeathing zombie years to the children we love is nothing less than devastating. But make no mistake, we are doing exactly that.

The gap between years spent alive and years spent truly living is a genuine zombie apocalypse, and it is already rather well established, and it looms ahead for us and for our children. Don’t expect modern medicine to fix it for you, no matter what happens with health care reform.

David L. Katz is the founding director, Yale-Griffin Prevention Research Center. He is the author of Disease-Proof: The Remarkable Truth About What Makes Us Well.