The Battle of the Bulge

By Numbers

Chances of a child being struck by lightning: 1 out of 1,000,000

Chances of a child being in a car accident: 4 out of 100

Chances of a child graduating from college: 30 out of 100

Chances of a child becoming fat: 33 out of 100

Chances of a fat child becoming a fat adult: 80 out of 100

Think for a moment about these odds, and the amount of time and energy we put into either preventing or encouraging those outcomes. We ticket parents who do not have their children in seatbelts, and have extensive school-zone speed limit laws to protect them from motor vehicle injury. We have entire national systems in place to encourage education and support our children in attaining a college education, even putting a significant portion of our tax money into it — in essence mandating that it is our civic duty. In some states, we even pay for college to help as many students as possible to receive a college diploma. But we do very little to prevent childhood obesity, the most likely of these outcomes.

We have certainly arrived at the point where our children are experiencing near-irreparable harm as a generation, but we did not get to this point overnight. The causes of the continuous shift toward weight gain are deep rooted and incredibly complex, but much of the problem has come from a history of ignoring both the presence of the issue and its long-term impact.

THE WORST-KEPT SECRET IN AMERICA

Why has the seemingly innocuous bathroom scale become our enemy? It is always there in your bathroom, just waiting for you to call on it. It always tells you the truth, no matter how much you don't want to hear it. And it never, ever, tells someone else your secret weight. But we've become so weight sensitive that we want to hide from the scale — if we don't know our own weight, then we can't get upset about what it is. In essence, we can keep our weight secret even from ourselves.

About that "secret," though — weight is not secret. It is one of the most obvious and plainly visible facts about ourselves, no matter how hard we might try to mask it in dark colors, vertical stripes, or multiple pairs of Spanx. And by masking it, not talking about it, pretending it's not there, we have created an environment of weight ignorance. And weight is like a wild animal — you should never turn your back on it.

In the case of our children, we have most definitely turned our backs on the beast. The weight of our children has slowly progressed to the point of being a true public health crisis. Many researchers saw the problems coming years ago, but we were either unable or unwilling to consider the fact that we were truly harming our children — that it wasn't just a little extra weight, but something that was going to have a dramatic and systemic impact. The cumulative health effects are so pronounced that obesity is quite literally taking years off children's lives, and that represents an ultimate failure on our part as a society.

To help frame the rest of our discourse, let's first take a look at definitions of fatness for children. You may be surprised at how complex these definitions are, but as we move through this book it will help give us a vocabulary for both describing weight and for seeing what role misperceptions and simple semantics have had in sustaining our children's weight problems.

MEASURING FAT

So how do we actually determine if someone is or is not fat? In general, most methods separate individuals into four groups: underweight, normal weight, overweight, and obese. For our purposes, the two levels of "fat" are, of course, overweight and obese. In scientific terms, being "overweight" means that an individual is at increased risk for health-related complications because of their elevated body weight. People in this range are generally no more than 35 pounds overweight. Individuals past this range are considered "obese," meaning that they are at high risk for health-related complications (particularly diabetes and a variety of heart diseases) due to elevated levels of body fat. At the high end of obesity lies "morbid obesity," which indicates an individual is at severe risk for health-related complications and, more often than not, already has one or more medical conditions directly related to their weight.

There is no precise way to determine the exact point at which someone transitions from being normal weight to being overweight, or from overweight to obese. Weight is a continuum, and a person's "ideal weight" is as individual to them as a fingerprint. Unfortunately, the lack of a universal "cutoff" allows people to somewhat ignore the problem until it becomes extreme.

Much of the difficulty in classifying people by their weight comes from the fact that when looking at health, we cannot simply consider an individual's weight by itself; other factors, such as height and body composition (amount of muscle vs. fat), are essential in determining a person's ideal weight. Defining obesity is a tricky concept in general because of this, and countless methods ranging from newfangled "impedance machines" (which estimate your body fat by sending a jolt of electricity through your body) to submersion tanks (which determine your body volume and by proxy the amount of fat in your body by seeing how much water you displace when you are submerged in a tank) have been invented in an attempt to clarify the topic. As these methods are obviously not suitable for widespread use, a more simplistic method had to emerge. The main consideration with weight is that a method of determining if someone is overweight must be able to say that for a given height, that individual has too much weight. As a result, the most common method of measuring the appropriateness of weight is the body mass index (which is calculated directly from an individual's height and weight alone).

BODY MASS INDEX

Estimating what portion of an individual's weight is attributable to fat has been a target of science for over 150 years, long before obesity was perceived as a threat to the health of the population. In the first half of the nineteenth century, Adolphe Quetelet proposed what was then referred to as the "Quetelet Index," which was a simple ratio of a person's weight in kilograms to their height in meters squared. This method was among the first to attempt to take the individual's height into account when determining a "normal" weight. This index was coined the body mass index (or BMI) more than one hundred years later. Nowadays, countless websites offer "free BMI calculators" that claim to tell you what the ideal weight is for a person of your height, and "BMI" has started to become a part of our general vocabulary. While its utility in describing groups of people has been well-recognized, the BMI was never intended to be used to diagnose individual health. In essence, it was designed to tell us how overweight a group of people is, not a single individual. But because of its relative simplicity and its ability to combine height and weight into a single health indicator, it has become by far the most widespread measure of weight ranges currently in use.

To calculate BMI, you take weight in pounds, divide it by height in inches twice, then multiply by 703. For instance, the BMI for a 180-pound man who is 5'8" tall (or 68 inches) would be: 180 ÷ 68 ÷ 68 x 703, which would be a BMI of 27.4.

The range of BMIs considered "normal" has changed over time, and has only been concretely defined for adults (not children). Currently, adults with a BMI between 25 and 30 are considered overweight, and adults with a BMI of 30 or greater are considered obese. These cutoff levels were revised under the recommendation of the National Institutes of Health (NIH) in 1998, perhaps in response to growing concerns over the weight of the nation. Prior to 1998, a BMI had to exceed 27.8 for an individual to be classified as overweight — with the change in BMI cutoffs in 1998 an estimated 25 million Americans who were previously considered normal weight were instantly reclassified as overweight to reflect the latest scientific evidence for the risk their weight was placing on their overall health. Prior to the new cutoffs, despite being at risk because of their weight, they were told they were normal and did not need to lose weight. This early misperception of healthy weight helped put in place a culture that was more accepting of higher weights, skewing our perception of what is "normal." Further reflecting the cultural nature of notions of ideal weight is the fact that some countries, such as Japan and Singapore, have even stricter BMI cutoffs than the U.S. revised standards; for instance, both of these Asian countries use a BMI of 23 as the transition point between normal weight and overweight.

Let's consider the standardized overweight cutoffs in weight for an average-height man. For the average man who is 5 feet 9 inches tall, a BMI of 27.8 (the original cutoff) was about 190 pounds. For a BMI of 25 (the current cutoff), overweight is reached at 169 pounds (a 21-pound difference). For Japan's definition of a BMI of 23, overweight would be reached at 156 pounds, representing a difference of nearly 35 pounds between the original U.S. definition of overweight and the current Japanese definition. The cutoffs are constantly debated, but the variation that exists indicates the wide range of weights that are considered "normal" even using a standardized measure — it's no wonder none of us knows what an ideal weight really is.

As you can see, while it gives a nice, tidy number, BMI is not easy to interpret. Even beyond the relative arbitrariness of the cutoffs, one of the main challenges that the BMI presents is the fact that the number doesn't have any meaning in and of itself. If I know my BMI is 26, it doesn't tell me how much weight I need to lose, or how much my risk has increased. This severely limits its usefulness in everyday practice, but despite this fact it has become widespread not only in the research community, but also in the general public.

For lack of another option, in the remainder of this chapter we will consider an adult BMI of 25 as the cutoff for overweight and an adult BMI of 30 as the cutoff for obesity (as these are the federally defined criteria used in the United States today). BMI cutoffs for morbid obesity are less clear, and vary by agency, but typically involve BMIs of 40 or higher; a common definition of morbid obesity is also being more than 100 pounds overweight (regardless of actual BMI). These definitions only apply to adults though — measures of obesity in children are even more complicated (if you can believe that).

CHILDREN: FAT OR NOT FAT?

Measuring weight status in children is significantly complicated by the fact that children's bodies change over time. If a four-year-old has gained five pounds, is it developmentally related, or is it excess weight? When you think about it, it's even possible that the five-pound weight gain is not enough for where the child is developmentally. How can we determine if that child's weight gain, and therefore the underlying weight itself, is appropriate?

The first set of childhood weight standards was used in the United States in 1977 to help parents determine if their child was growing appropriately. They were based upon data that had been collected for decades by the National Center for Health Statistics within the Centers for Disease Control and Prevention (CDC). As the federal agency tasked with actively protecting the nation's health through prevention, CDC has been one of the most active federal agencies in addressing childhood obesity. CDC researchers are also responsible for monitoring the overall health status of the nation, and as such have unique resources and continuous research studies that allow them to best quantify where children's weights stand for the purposes of developing population norms. Based on their data drawn from tens of thousands of U.S. children, the CDC developed comprehensive growth charts that defined where any child's height and weight fell in comparison to others of their age.

Unfortunately, at the original construction of the national growth charts in 1977, childhood obesity was so far off the federal radar that a chart was not even created for BMI. At the time, all you could do was compare the weight of your six-year-old to the weight of other six-year-olds; you could not compare BMIs, which would take the children's height into account. While there were height-to-weight charts included in the 1977 release, they were not based on any scientific standard, such as the BMI, and were of limited utility. Again, at the time, federal officials were not focused on the need to establish overweight and obesity cutoff scores, so it simply did not happen. This oversight in the original 1977 charts left no true national comparison point that could be used to set a standard for childhood weight. These 1977 charts remained the "gold standard" for assessing healthy childhood growth for more than twenty years, during which time children as a whole became heavier and heavier (without any comparison point for us to truly measure what was happening).

As the childhood obesity epidemic began to grow, medical experts realized that the lack of an established system to classify the appropriateness of children's weights was dramatically impairing their ability not only to track the growing problem, but even to tell a parent if their child was overweight. In a vivid display of what can happen when scientists and policy-makers become so bogged down in the details that they lose sight of the big picture, the debate over the relatively straightforward question "When is a child fat?" has raged on for decades. In the process, the issue has become so obfuscated that it is absolutely no surprise that as a society we missed what was happening. Case in point: almost exclusively because of arguments over semantics (literally), until the year 2010 there was no BMI that a child could reach that would lead them to be classified as obese using federal standards. The worst a child could be called was overweight, and even that label required unreasonably high levels of excess weight.

How did this happen? Well, the effort to define appropriate weight for children started out with the best of intentions. As of the 1990s there were no widely functional measures to determine the appropriate weight of a child; techniques that attempted to move beyond a child's simple weight relied upon methods that actually physically measured body fat using calipers (pincers that measure the thickness of the fat layer under the skin) or through other physical measures of the actual quantity of fat, not weight. This unfortunately left not only physicians, but also the general public, without an easy method to determine if their child had reached a concerning weight.

What to do? Naturally, form a committee. Mirroring the movement toward the use of BMI in adults (and thereby height-adjusting the associated weight), a federal expert committee was appointed in the mid-1990s to decide what official measure and what cutoffs of that measure should be used to determine at what point a child has reached obesity (with BMI identified as the most likely candidate). The panel included leading obesity experts and was populated and shaped by the American Medical Association, the American Academy of Pediatrics, the Centers for Disease Control and Prevention, the National Center for Education in Maternal and Child Health at Georgetown University, and the Maternal and Child Health Bureau of the federal Health Resources and Services Administration. After much deliberation, the committee came to the conclusion that, despite its known limitations, BMI should be the official measure used to determine the weight status of children.

Ironically, in the first of many steps that would only serve to mystify the process, the committee tasked with creating an official federal measure for obesity got so bogged down in precision that they entirely rejected the use of the word "obesity" for any level of BMI (their own chosen measure). Stating that BMI is technically a measure of weight and not of body fat, the committee decreed that the traditional "overweight" and "obese" continuum used for adults should not be used for children, and instead created two levels of childhood fatness: "at risk for overweight" and "overweight." Their argument for not using "obese" to describe the highest BMIs? You couldn't be "sure" that a child at any BMI technically had too much body fat; there could always be a child with extreme muscle mass or another non-fat related issue that skewed their BMI.