First of all, the answer, sadly, is YES. I was not imagining it, as I travelled across Europe with my friend, M., eating the same foods, walking the same (long) distances, engaging in the same activities, and gaining weight while she lost weight. We are not created equal.
In a recent post, I talked about how we have internalized hatred of the overweight, how cruel and hateful we can be towards ourselves for the slightest transgression from the one true path of calories in and calories out.
Not so fast, honey.
Yes, there are people--many people, many weight loss bloggers, in fact--who are serious overeaters. These are the people who stuff their faces silly to tamp down feelings, pain, horrible recollections. These are the binge eaters, the emotional eaters, the ones who trade horrible psychological pain for the pain/pleasure of a belly stuffed so full they cannot move.
It seems pretty obvious that all these people have to do is cut down their food intake and all will be well.
But let's look again.
Once in a while, we hear about Hollywood stars who have to gain a large amount of weight--who have, for all intents and purposes, had to "stuff their faces"--for a particular role. Renée Zellweger as Bridget Jones comes to mind. According to this article, gaining weight was "just a job" for her. In fact, she worked with a nutritionist to gain the weight. Although I have no doubt that she also worked assiduously to regain her figure afterwards, how often do we hear about Zellweger's battle with excess weight since having lost the weight? I can't recall any articles about such a problem, just articles about how (sigh) she has to gain the weight back yet again for a sequel. Compare Zellweger to Jessica Simpson, who worked like a dog to achieve slimness for the Dukes of Hazzard movie but is now often featured in the tabloids for her weight "problems". Poor child, she just can't stay stick thin.
My point is that a naturally slim person like Zellweger who has consciously made an effort to gain weight (who has stuffed her face like a binge eater), will lose the weight and keep it off once that effort is removed. Someone with more of a tendency to gain weight (like Simpson) will have to work hard to lose the weight and will continue to have to make serious efforts to keep it off once the desired weight has been reached.
And this why you MUST read this article: "Understanding the Physics of Weight Loss", by Dr. David Katz.
In the article, Dr. Katz explains that while we are all the same in terms Newton's laws of physics (i.e. calories in vs. calories out), we are not all the same when it comes to two other important factors: heat generation (thermogenesis) and resting energy expenditure (or the basal metabolic rate). While we do have control over the number of calories we ingest and the amount of exercise we do, we have no control over how much heat we generate from the calories nor how many calories we use up to simply continue living.
You can choose how much exercise to do. But you don't get to choose how thermogenic you tend to be, and that can matter quite a lot. Like exercise, thermogenesis accounts for roughly 15 percent of total energy expenditure on average, but there is lots of variation on the theme of average. People who generate more heat from calories have fewer available with which to make fat. They tend to be people who can eat a bit more, and stay thin anyway.Dr. Katz goes on to cite the case of the Pima Indians, who naturally have a very low resting energy expenditure rate. Living in an unforgiving, harsh desert climate, their bodies evolved into energy conservation machines. Surviving in their environment required expending a lot of energy, and conserving as much energy as possible became a physical survival mechanism. Like camels, who are physically equipped to carry water in their bodies to make up for the many miles they walk through the arid desert, the Pimas' bodies hold onto calories, that precious commodity that enables them to survive in an environment where most of us would die. However, the world has changed and survival is a lot easier now. Unfortunately for the Pimas, their bodies have not evolved to catch up with these changes and they are amongst those who have the highest rates of obesity and diabetes in the world.
But that's a drop in the bucket compared to resting energy expenditure. Roughly 65 percent of calories are burned to support the fundamental workings of cells and organs that keep us alive. The number of calories burned at rest, and the actual percentage of total calories burned this way, also vary substantially around the average. People with a high resting energy expenditure are, in our modern world of epidemic obesity, the fortunate few most people love to hate: the folks who cannot seem to get enough to eat, and can't put weight on when they try.
Although I am not a scientist, I would also apply Dr. Katz's explanation of the differences in weight gain/loss/maintenance between individuals to the differences between men and women. I have said before--and I truly believe that the numbers back me up--that women have a much harder time losing and keeping the weight off than men due to hormonal differences. A woman's weight is an important factor in her fertility. While it is true that obesity can be an impediment to fertility, I suspect severe underweight is an even more important factor. When a woman loses her period due to excessive caloric restriction (often coupled with obsessive exercising), getting pregnant becomes next to impossible. So Mother Nature, in her wisdom, has made it even harder for women to lose weight than men. The world needs babies and Mother Nature is going to make sure that we make them.
In the final analysis, I am not saying that we should all give up. Not in the least. If your diet is mainly composed of Big Macs, Cheezies and Coke, you're likely to be both overweight and malnourished. If you'd rather take the car than walk less than 3 minutes, you're probably in terrible shape. (True story: recently, we went out to supper with a friend at a restaurant about 3 minutes walk from our home. He arrived by car at our house and I motioned for him to park in our driveway. Instead of parking, he rolled down the window and offered us a lift to the restaurant. I was shocked but not surprised: he's in terrible shape. We walked, he took the car and parked in the underground parking lot below the restaurant. Interestingly enough, we got there first.)
So let's stop castigating ourselves and others. Let's make a conscious effort to feel compassion rather than disdain for the severely overweight amongst us. Personal choice is just one piece in the much more complicated puzzle of weight management.
Hard as it may be, let's make MORE of an effort to eat well and exercise responsibly while recognizing that we have much LESS control over the scale than we'd like to think.
Yes, Virginia, to a certain extent it IS your metabolism.