Statistical Artifact

I've discovered a new diet. There is no need to exercise, no need to change what or how or when you eat, no need to count calories or worry about grams of carbohydrates or fat. All you need to do is wait--and grow older.

I was hugely fat in high school. Okay, maybe not hugely fat, but that's the way I remember it. Lots of embarrassed trips to the cafeteria to buy those huge, glazed cinnamon rolls; lots of late night trips to the refrigerator for ice cream; lots of secret (or not so secret) forays to the convenience store for pies, cakes and cookies. I wanted to stop, but I couldn't help it, and worse, since I was on the swim team, my failing was there for everybody to see. It was awful. I would promise myself with every binge that it was to be the last and that tomorrow I would start a proper diet, but, almost inevitably, there I would be the next night, sneaking into the kitchen for yet another gorge. Thinking back on it, it's hard to believe I survived, but, there you go, the resiliency of youth. Or maybe all that exercise at swim practice. In any event, I got fat, gaining a good thirty pounds between ninth and twelfth grade. I was, if not in fact the heaviest in my class, certainly up there with the heavier, definitely not a cheerleader.

Now, nearly some thirty years later (can I really be that old?) I have, as you know, struggled my way through various diets or not-really-diets trying to learn how to eat in a way that will keep me healthy and allow my body to attain its proper weight. I exercise a fair amount, but nothing like as much as one would, say, to train for a marathon. I eat well, no meat, lots of fruits and vegetables, maybe a few too many cookies, but nothing like those teenage blowouts (analogs, I dare say, of the drinking that I did at college parties). And, even if I have been at times ten or so pounds overweight, I wouldn't say I'm fat. Now, in fact, after this past month's mindful eating, I'm feeling positively slender, nearly my perfect weight. Another five pounds or so and I'll be golden. But get this: when I got on the scales this morning (yes, I still weigh myself; it's hard to stop counting after so many years), I weighed...exactly what I did my senior year in high school before I went on my only ever true "diet."

How can this be? Enter our friendly neighborhood BMI calculator. According to this calculator, which you can adjust for age and sex as well as weight and height, even when I was in high school and feeling so hugely fat, I was still in what the WHO-CDC considers "normal range" for my height and age. I was, however, by current statistics, at the 55th percentile compared with other Americans. Mind you, this is a percentile for 2009, not 1982, so perhaps my perception of being significantly heavier than most of my classmates is actually still accurate. They do say that Americans are on average heavier now than we were thirty years ago. But let's just say for the sake of this exercise that the percentiles hold. At age twenty-five, at the same weight, I had dropped to the 45th percentile; by age thirty-five, still at the same weight, I was only in the 31st percentile. Now, at age forty-four, lo and behold! I'm thin--or, at least, only in the 22nd percentile. Without losing a pound. Of course, I have gained and lost over the years, so this exercise is not a true description of my experience, but as a statistical artifact, it is fascinating. You mean, all I had to do not to be fat anymore was...grow up?

Do you think I could make any money off of this? I could call it the "Aging Gracefully" diet. No, better: "Weigh What You Did in High School." Of course, it requires everybody around you to be gaining weight for the percentiles to change, but think of all the misery it would have saved me in high school to know that I had simply reached my proper, adult weight a little early.*

*Actually, I'm not sure that this is what happened. I was heavier than I probably should have been in high school; certainly, I was not physically comfortable at this weight. The lesson here is something subtler, about how bodies age and how one's "proper" weight may actually change over the years. But it's still a fun artifact, don't you think?**
**Interestingly, I'm not the only one to have discovered this artifact. Nora Ephron has a very similar story in I Feel Bad About My Neck and Other Thoughts on Being a Woman (2006), entitled "I swear to God Janice Glabman will never laugh at me again" (pp. 99-100): Ephron comes back from college twenty pounds heavier than she was when she started and goes to her "fat" friend Janice to borrow some clothes, but she is too heavy even for Janice's clothes and Janice laughs at her. The next day, Ephron goes on diet, drops the twenty pounds and stays on a diet ever after that. The punchline: "I have not seen Janice in more than forty years, but if I do see her, I'm ready. I'm thin. Although I now weigh 126 pounds, the exact amount I weighed when I came home from college having become a butterball. I can't explain this."***
***Just for the record: 126 pounds was probably my ideal weight in high school. Now, if I weigh that, I look like a marathon runner. My body seems happier ten or so pounds heavier.