the role of genetics
I call my mother’s side of the family the Dominant Gene Family. This is because they all look alike. The men are spitting images of one another, separated from identical twindom only by differences in age. The dozen or so women have slight differences in their bodyfat deposition patterns, with some being more apple- than pear-shaped, but there are no tall lanky ones lurking among us. Put our faces side by side and it starts to look like some kind of X-Files cloning situation. My genetic inheritance is pretty clear.
Yet even among this genetically similar group of Eastern European peasant stock, there are differences. And the differences are clearly connected to our choices of activity and nutrition.
For example, my mother and her sister look a lot alike. They both have dark hair and eyes, the same distinct nose, many of the same mannerisms. They are both short, stocky, and rounded. My aunt has struggled for years with obesity. Her tiny frame objects to the load it carries; her knees have been operated on several times, her hip bothers her, and she has difficulty walking. In 2006 she was in a terrible car accident that crushed her feet and ankles. She now has even more trouble getting around.
My mother has also struggled for years to maintain a healthy weight in the face of hypothyroidism and cancer. Unlike her younger sister, she has been successful in this project. The key difference between the two is their lifestyle. My aunt loves fatty foods, bacon, butter, pirogi, potato chips, and anything that suggests comfort. I wouldn’t challenge her to a drinking contest either.
My mother, on the other hand, has a B.Sc. in food sciences and worked as a nutritionist. She rarely drinks, always eats her veggies and vitamins, and no matter how cold or crummy the weather, doesn’t miss her daily brisk walk around the neighbourhood. In her life, nutrition and activity are non-negotiable items. Now in her sixties, she maintains a healthy body weight for her age and body type, and looks younger than her baby sis.
what do genes do?
Genetics are only blueprints — work-in-progress guidelines. They are not a destiny.
Genetics tells us what will happen given certain environmental conditions. We might say that I am genetically programmed to gain fat if I eat 5000 calories a day. But we might also say, equally correctly, that I am genetically programmed to lose fat if I eat 1000 calories a day.
Given the condition that both my parents have the dominant gene for brown eyes, and that everything else is in place to allow that gene to be expressed, I will have brown eyes. Quite often, even for something simple such as eye colour, there needs to be, say, one gene that says “brown eyes” and another one that says, “make ‘brown eyes’ happen”. Our environment can influence, or control, the expression of our genes. And in fact, in the case of some genes, this change to the expression can happen at any point in a person’s life.
A very useful (though unfortunate and tragic) example comes to us from indigenous societies who transitioned to eating and living in Anglo-European ways within recorded history. (Gary Taubes and Michael Pollan describe this at length in Good Calories, Bad Calories and In Defense of Food, respectively.) Indigenous societies are a good population group to study because their genetics are relatively discrete: they may have been living in more or less isolated communities for generations — perhaps centuries. Indigenous societies living on traditional diets typically had very low incidences of many chronic diseases that we assume are commonplace: obesity, heart disease, cancer, periodontal disease, etc. When they adopted Anglo-European foods and living patterns (or had these forced upon them), which included sedentary lifestyles and processed foods high in artificial fats/vegetable oils, sugar, and chemicals, their health drastically declined. In the case of groups such as the Pima, the outcome was disastrous. And yet, people’s genetics have not radically changed in only a few generations. Even more interestingly, well-controlled studies have shown that indigenous people can reverse these effects by returning to traditional ways of eating.
- My Big Fat Diet – an experiment with Namgis First Nation on Canada’s West Coast
- The American Indian Health site for more reading about indigenous diets and wellness
- South Sea islanders and the New World Syndrome that causes formerly robust people to die in their 30s, 40s, and 50s
“Genetics” is also frequently invoked to explain superior athletic performance. It’s clear that elite-level competitors have some kind of intrinsic ability to perform their chosen activity. But “genetics” for what, exactly? What makes someone run faster? Their muscle attachments? Their reaction time? Their femur length? The strength of their hip extensors? The elastic energy in their ankle tendons? Why are gifted sprinters not the same as gifted endurance runners? Etc.
Let’s say we have an athlete who is genetically gifted. Every ball she throws hits the target dead on. She is the fastest and strongest athlete on the field. Her body is a slab of rippling muscle ennervated by lightning reflexes. But what if she doesn’t have any interest in training hard, constantly striving to improve her performance, and focusing on her goals? What if she just can’t be bothered get out of bed in the morning? Is she going to be an elite athlete? Probably not. Genetics alone isn’t going to make her an elite athlete if she doesn’t get off her ass.
To further muddy the waters, consider this excerpt from the work of Karl Anders Ericsson, which explores the role of practice and skill learning/mastery:
When experts exhibit their superior performance in public their behavior looks so effortless and natural that we are tempted to attribute it to special talents. Although a certain amount of knowledge and training seems necessary, the role of acquired skill for the highest levels of achievement has traditionally been minimized. However, when scientists began measuring the experts’ supposedly superior powers of speed, memory and intelligence with psychometric tests, no general superiority was found — the demonstrated superiority was domain specific. For example, the superiority of the chess experts’ memory was constrained to regular chess positions and did not generalize to other types of materials. Not even IQ could distinguish the best among chessplayers nor the most successful and creative among artists and scientists. In a recent review, Ericsson and Lehmann (1996) found that: (1) measures of general basic capacities do not predict success in a domain, (2) the superior performance of experts is often very domain specific and transfer outside their narrow area of expertise is surprisingly limited and (3) systematic differences between experts and less proficient individuals nearly always reflect attributes acquired by the experts during their lengthy training…
[W]orld-class [chess] players did not differ in the speed of their thoughts or the size of their basic memory capacity, and their ability to recognize promising potential moves was based on their extensive experience and knowledge of patterns in chess… According to [one] influential theory, expert performance is viewed as an extreme case of skill acquisition.
From “Expert Performance and Deliberate Practice“. For more reading, see Starkes, Janet L. and Karl Anders Ericsson. Expert Performance in Sports: Advances in Research on Sport Expertise Champaign, IL: Human Kinetics, 2003.
In other words, people can be generally gifted by virtue of some arrangement of their genetics. But the ways in which they develop those abilities and excel can be very, very specific. (We all know brilliant people who are helpless outside their domain of expertise. My PhD dad bought an ab gizmo from an infomercial. Nuff said.)
The other take-home here is that excelling takes a lot of work… but doing “pretty good” likely doesn’t require either elite genes or an elite work ethic. You can be a pretty good anything if you roll up your sleeves and bust out a little elbow grease. In this case, you can certainly maintain a healthy level of bodyfat with good nutrition and regular activity, regardless of what your bossy-assed genes think.
We now know that there is no single gene that controls something as complex as metabolism or athletic performance. We also know that in the case of genetics and bodyfat levels, genetics is only one part of the puzzle. Genetics can only create a plan of action for various contexts. Your behaviour and environment do the rest.
what mom and dad also gave you: family dynamics
Genetics aren’t the only thing that bring families together. Social factors also play a role. Your family teaches you how to live. (And if they can’t be a shining example, hopefully they can be a cautionary tale.)
A recent article in the American Journal of Sociology explored the relative roles of genetics and social factors within families. Social factors can be many things:
- the messages that your family communicates about food and exercise (e.g. food is love; or food is a cause of angst)
- the things they do (e.g. eating meals together, or not)
- the behaviour and habits they model and reinforce (e.g. chronic dieting or overeating; active family outings)
- the knowledge and information they transmit (e.g. from parent to child)
- how they communicate that knowledge and information (e.g. positive reinforcement; criticism; spoken and unspoken rules)
As the authors explain:
[P]arents socialize their children to share similar values, attitudes, and behaviors related to eating, physical activity, and weight concerns… From an early age, parents model their weight-related preferences and orientations as well as their level of self-restraint.
Using longitudinal data, the researchers examined siblings within families. Their conclusions?
Genetics plays a significant role in determining an adolescent’s weight, but families’ social and behavioral characteristics are also important. Furthermore, incorporating genetic information not only reveals that familial social patterns compound biological weight trajectories; it also illuminates the fact that the association between inactivity and adolescent weight is embedded within a family’s collective lifestyle.
In other words, it’s both nature and nurture.
Interestingly, by the way, the researchers also note that immigrants to North America are usually leaner. Their children are relatively fatter. Genetics don’t change drastically in a single generation — but the environment does.
DNA ain’t destiny
I used to think that my body composition was my genetic fate, given the rest of my family. I felt very out of control. I felt like everything had been preplanned for me and I had had no say in the matter. I now know that my genetics are only a predisposition, not an unalterable fate. Given a context of caloric excess and sedentary living, I will become overfat. Given a context of regular activity and controlled, high quality nutrition, I will stay lean. The same genes that say I’ll be out of shape when I do X also say that I’ll be fit when I do Y. Boy was I relieved to discover that I do have control over my fitness and health! Phew! Now that seems kind of dumb, but we are all experiential learners and sometimes the simplest, most obvious things… aren’t.
People are often shocked to hear that I was once quite overfat. They can’t believe that the tiny grrl in front of them once resembled a Weeble. But it’s true, and I have the photographic proof. If you could look inside my genes, you’d see the proof there too — very likely, you’d find plenty of blueprints for obesity, heart disease, and the like. But I’ll be damned if I always let those DNA bastards tell me what to do. Genetics are, as Bill Murray said to Sigourney Weaver in Ghostbusters, more of a guideline than a rule.
the “health conspiracy”
Another thing I hear a lot of in certain circles is that there is some kind of conspiracy among health care professionals. There are various nefarious parties: the Medical Establishment, the Nutritional Cabal, the Rabbit Food Cultists. Usually The Media factors in there somewhere too. Now, I’m the first to admit that many general practitioners aren’t exactly hipsters when it comes to the latest clinical data on fitness and nutrition, but still, as I understand it, one has to have some rudimentary grasp of physiology to graduate from med school.
And let’s all agree, shall we, that anything produced by the mainstream media is probably a steaming pile of cow poopie. Frankly, we would all gain about 20 IQ points just from throwing away every mainstream media product and celebrity-and-advertisement-riddled-tabloid in a 50-foot radius. It’s stupid and it’s making us all stupiderer. And it has nothing to do with our real lives.
That being said, I have to point out that THERE IS NO NUTRITIONAL AND FITNESS CONSPIRACY. Oh sure, there are studies funded by the Butter Council or the Association of Meat Marketers or whatever. There is a fitness, diet, and supplement industry that enjoys leaching cash from people who are vulnerable. But this is where your brain comes in, now that you’ve given it a nice little freebie from ditching the Cosmo shit.
Scientific studies popularized in the mainstream press are usually overblown, overhyped, and sometimes, even completely contrary to what the researchers actually found. Don’t get your information from there. Get it from a reliable source like PubMed, the Berkeley Wellness Letter, or the Harvard School of Public Health. Go to the library and find books on nutrition and exercise, and make sure they’re not published by the California Institute of Enlightenment. Look for a university or other academic affiliation. Hell, look for a bibliography in the back, at least. Sorry to be elitist but that’s how it goes. One book I recommend for nutrition is Walter Willett’s Eat, Drink, and Be Healthy. For other book recommendations and tips on how to evaluate research, check the “Learning” section of this site.
Look at the information critically. Think about its applicability to you. Was it done on rats? Then it might not mean quite as much to humans, except as a clue for future research. Was it done on people in some weird situation, like crash dieting or living in war zones? Was it done with a sample size of 9 people? Is it extrapolating some small result to a larger population, or making grandiose claims for modest findings? Is the “data” anecdotal (“Bob says this works great for him”) or empirical, based in actual clinical studies?
There is no anti-fat medical conspiracy. There is no exercise conspiracy. There is only media hype and clinical research. There are the laws of thermodynamics, which apply to all of us, and they stipulate that energy can’t be created from nowhere. Calories in and calories out have a relationship. There are realities of physiology which we can choose to confirm or deny, but which do not go away for our denial.
So what does all of this mean? The conclusion is sort of boring, really. In my experience, what I have found is that people who eat well and exercise as a means of achieving self-care and wellness succeed. People who eat well and exercise only as a stopgap for their bad habits (“I ate an apple, now I can eat a cookie”, or “I walked on the treadmill so now I can belt back this fifth of JD”) do not. And by succeed I do not mean squeezing into a size 4. I mean living life happily and healthily, at whatever size that is. If your bodyfat level is having a negative impact on your health and athletic performance, then consider dealing with it through positive fitness and nutritional practices. If you are fit, meeting all your goals, kicking ass in your medical tests, and feeling great, then keep doing what you’re doing!
Exercise and eat for health and wholeness, whatever your size or shape. Remember that one day you might need to move a couch or run for safety on short notice.
Take care of your body because you love it, not because you hate it. Be fit and well in the way that works for you. Don’t participate in self-delusion, but don’t beat yourself up either. Care for your insides and your outsides. And of course, eat your veggies because hey, mom was right, they are good for you.