Why Weight Control Needs to Start Early

In my prior column, which was about the importance of cultural rather than just clinical approaches to the treatment, control and prevention of obesity, I compared weight control to a space mission. The best opportunities for defense of the flight plan come early. With space travel, constant vigilance and early corrections are far better than trying to get back into the right solar system after a long and inopportune nap.

With weight control, similarly, the best opportunities come early; ounces of prevention quite literally prevent the need for pounds of cure. Pounds of cure are, of course, possible -- and some do manage to lose the weight and keep it off for good, so by all means, keep at it and keep the faith if you need to get back on course. But doing so is hard and relatively elusive, and most of us struggling to get weight under control struggle for the long haul. We are better off avoiding the struggle in the first place.

[Read: Understanding Childhood Obesity.]

And that, of course, means avoiding obesity in childhood -- also a challenge in an age of epidemic childhood obesity. We have long known that childhood obesity predicts obesity later on, and that obesity at or around puberty is a potent predictor of adult obesity, its common metabolic complications, and that lifelong struggle we all hope to avoid.

To whatever extent we were not entirely convinced already of the advantage of ounces of prevention, a study just published in the New England Journal of Medicine, and attracting such prominent media attention as front-page placement in The New York Times, should finish the job. From my perspective, the study makes a compelling case for family-centric approaches to health and weight control.

As with all research, the details matter, but in this case, the fundamentals are simple, refreshingly transparent and largely immune to any deviltry. The researchers simply tracked a nationally representative cohort of roughly 8,000 kindergartners for roughly nine years, and monitored the change over time in body mass index. What they found was that obesity and overweight developed predominantly by age 5, or not at all. In other words, if we can indeed liken the trajectory of weight over a lifetime to a space mission, our kindergartners are the kosmonauts.

Children subject to obesity or overweight by kindergarten were much more likely to be overweight or obese as tweens and teens. The development of overweight and obesity dropped off steeply over time, meaning that those kids who dodged this bullet for the first five or six years of life generally did so throughout childhood.[Read: 7 Family Fitness Ideas for Winter.]

This has profound implications. First, as noted there has long been evidence that obesity at or around puberty is a potent predictor of adult, and consequently lifelong obesity. Connecting the dots here gives us this: avoiding obesity in early childhood markedly increases the likelihood of avoiding it at puberty which in turn increases the likelihood of avoiding it forever after. The converse of this causal pathway is, of course, the corresponding bad news: get it wrong early, and a lifelong struggle with weight is apt to ensue.

There are even some rather compelling physiological explanations for this. We can grow new fat cells at any time during our lives, but we do so most readily during times of normal growth-namely early childhood, and around puberty. Most weight gain in adults, unless it's extreme, involves overstuffing the fat cells we already have. While the enlargement of our established population of fat cells, termed hypertrophic obesity, can indeed make us fat, it comes with an advantage. Fat cells, or adipocytes, have a normal size range like all cells, and gravitate toward it. If fat cells are overly large, shrinking them back to within their normal size range is not effortless, but the cells don't put up too much of a fight.

In contrast, if we become obese by increasing the number of fat cells we have, termed hyperplastic obesity, we face a different and far greater challenge. If an excessive population of more or less normal-size fat cells is making us fat, the only way to be thin is to shrink those cells to below normal size by starving them, and ideally, starving some of them entirely out of existence. The trouble is, cells don't like to starve -- and fight this by every powerful means at their disposal, in particular the manipulation of hormones such as leptin that regulate our hunger.

[Read: 7 Steps to Successful Family Meals.]

So I trust you put this together the same way I do. When we let obesity develop in childhood, and it in turn propagates obesity at puberty, we are subjecting our children to the very variety of obesity that is the most difficult to manage or reverse. We are, in essence, dooming those children to a lifelong struggle with weight.

As loving and responsible parents, or grandparents, or aunts and uncles -- or just good people -- we can't do that. We have a responsibility to give our kids the best lives we can -- and the complications of obesity, both physical and psychological, aren't it.

And so it is that the topic of personal responsibility, one of the more polarizing issues in the weight control domain, deserves some reconsideration in the light of this new research. However views may differ about responsibility for better use of feet and forks -- a topic I have addressed many times before -- we can all agree that we should not be pinning the blame on 3-year-olds. The new study suggests that an overweight 3-year-old is much more likely to be an overweight 13-year-old, who in turn is much more likely to wind up an obese or overweight 33-year-old. An admonishing finger wagged at that 33-year-old therefore ignores the fact that they inherited a disadvantage from a time before their responsibility for much of anything had yet begun. This scenario argues for a responsible approach to weight control and the cultivation of health at the level of the body politic, or culture, rather than blaming the victims.

As one of the judges here at U.S. News for the annual "best diet" analysis, I have shared my views on the results and process more than once. I have noted in particular that we might all be better served by a recipe that combines the best elements of various dietary approaches rather than a competition among theories and ingredients. But my most consistent and adamant concern, expressed to our editors here, has been: What about family?

[Read: Gathering Your Family Health History.]

Dieting is an infamously go-it-alone endeavor. People eat with their families; but they "diet" without them. I think dieting should die, and we should live well together -- taking better care of our kids as a result.

There is a purely selfish case to make here, because dieting is a questionable practice even for the dieter. We all know, and probably believe the adage that "in unity, there is strength." Yet, with the particular brand of blind gullibility weight-loss wishes seem to induce, we routinely abandon that strength in an effort to lose 30 pounds in six weeks (or is it six days?). The result tends to be, as we all know from epidemiology and many of us from personal experience, success in the short-term, and then disaster. Absent the strength of unity, short-term weight loss almost inevitably converts into long-term weight regain with interest.

We should expect just this. In a modern environment that conspires mightily against healthful eating, routine exercise, and weight control, achieving any of these is challenging at best. Doing so while practicing Diet X for self and Diet Y for family is nearly impossible. It's certainly inconvenient, unpleasant and isolating.

So, even just for the selfish sake of the dieter trying to lose weight, it makes sense to adopt an approach that derives the strength of unity at the level of household. This, alone, might make the case. We and our children, we and our spouses influence one another. When we share activities and commitments, they become part of our routine, they take their place in family values, they are elements of culture. Culture, in turn, establishes the currents that flow through our lives -- and it is much easier to go with the flow than against it.

But as a parent, I don't think the benefit for self is the strongest argument for the salience of family in healthy living. The strongest argument is not about what others can do for us, but what we are obligated to do for them. Parents are obligated to defend the well-being of our children, and going on any kind of diet that leaves them behind is -- forgive the bluntness -- an abdication of that sacred responsibility. All the more so in an age of epidemic childhood obesity, and ever mounting evidence of its all-too-often dire consequences.

And yet, as a society we sanction a multibillion dollar weight loss industry for adults. We line up, sign up, go on and fall off -- all the while leaving our kids out of it. We just need to look around to see how well this is working out for adults. But more importantly, every time we neglect a family-based approach to health and weight control, we increase the likelihood that our children will grow up to need those weight loss services even more desperately than we do.

[Read: The Best Diets for Healthy Eating.]

The best way to lose weight is by finding health, and that's something we can do with and for our families, even in the context of appropriately designed weight-loss programming. What we can't do is look on at the trajectory of our children's health going woefully off course and wring our hands. Our kindergartners may be kosmonauts, but when they go off course, the fault lies not with our stars, but with ourselves -- for sanctioning a culture of go-it-alone dieting, and failing to make the journey to health -- together.

Hungry for more? Write to eatandrun@usnews.com with your questions, concerns and feedback.

David L. Katz, MD, MPH, FACPM, FACP, is a specialist in internal medicine and preventive medicine, with particular expertise in nutrition, weight management and chronic-disease prevention. He is the founding director of Yale University's Prevention Research Center and principal inventor of the NuVal nutrition guidance system. Katz was named editor-in-chief of Childhood Obesity in 2011, and is president-elect of the American College of Lifestyle Medicine. He is the author of "Disease Proof: The Remarkable Truth About What Makes Us Well."