Why You Shouldn’t Always Listen to Your Body

human-bodyLike for all other organisms, it’s our genetic blueprint that has been shaped over eons of evolution that lays the basis for our behaviour. We can certainly choose to live our lives in a specific way, but ultimately it’s our ancient instincts that largely explain why we do what we do. The fact that we have this inborn pattern of behavior might seem completely obvious, but it’s something that’s all too often forgotten – especially in the discussion of health & fitness. An obesity epidemic that has spread across the globe like fire in dry grass and a situation where sedentarism is the new norm in many parts of the world can quickly lead one to ask: Are humans just a bunch of weaklings lacking the willpower to eat healthy and exercise? To some extent, it could be argued that the answer is yes, as we clearly can choose a healthy path in life. However, what we have to remember is that we are simply dealt a hand of cards from our ancestors. A hand of cards that could have been a winning hand in prehistoric times, but a less than optimal hand in modern times…

To understand why things are like they are, we can always turn our attention to the roadmap that the science of evolutionary biology gives us. As I’ve repeatedly highlighted on this blog; we’re still largely stone agers from a genetic perspective, and our behaviours today can be traced back to things that have occurred in our evolutionary past.

It’s the struggle for existence in nature over eons of evolutionary time that has shaped our inborn patterns. The most obvious examples are perhaps our desire for sex and nutrient-dense foods, but our natural instincts also lay the basis for our behaviour in other areas of our life. Even our tendency to express ourselves through art and culture can be explained using evolutionary theory.

Perhaps most important for this blog is of course the instincts and behaviours that have a profound impact on our health…

How your ancient genes could be setting you up for sedentary behaviour and fast food consumption

In an ancestral natural environment, physical fitness was closely linked with darwinian fitness. If you weren’t able to handle a demanding hunter-gatherer lifestyle and survive until reproductive age, your genes weren’t passed on to future generations. Therefore, since physical fitness in some regards was a predictor of reproductive fitness in a prehistoric world, it makes sense that our evolved instincts and tendencies couldn’t have had a strong negative effect on physical fitness levels. However, in today’s world, where the bond between physical fitness and darwinian fitness has been loosened dramatically (we no longer have to be especially fit and healthy to survive and reproduce), the situation has changed…

Let’s take sedentary behaviour for example. For someone who goes to the gym rigorously 4 times a week in pursuit of his/her fitness goals, it might seem crazy that so many people give up on the new year’s resolution to “get fit” after only a few weeks in the gym or seemingly choose to be inactive for most of their life . However, when you look at exercise from an evolutionary perspective, the high drop out rates at your local gym doesn’t really come as a surprise. 99,5% of the evolutionary history of our genus (Homo) consists of a physically demanding hunter-gatherer existence, and in an ancestral environment, doing more work than what was necessary to acquire food, evade dangerous animals, take care of the young, etc. would only have been a waste of energy and decreased the chances of survival. Hunter-gatherers never go for a run or lift heavy things around if they don’t have to; they only “exercise” because they must. This inborn desire to relax when possible is a consequence of natural selection in the works, where advantageous traits (that help certain individuals survive and reproduce) are “selected” or favored by natural selection and are thus perpetuated through later generations.

We’ve essentially evolved to take it easy when we can, and it’s therefore no surprise that when we no longer have to move our bodies (to any significant extent) to survive, many of us become sedentary. Clearly, we can choose to go for a run or strength training session instead of sitting on the couch, but for many, biology overcomes willpower.

These same principles apply to other aspects of our behaviour. We eat hamburgers because we desire calorie-dense, palatable, and safe foods rich in starch, sugar, and/or fat, and we take hot showers instead of cold ones because cold showers provide an intermittent burst of stress and are more costly in terms of energy expenditure.

Inborn instincts that drive us to relax when possible and seek out calorie-dense, safe foods would have benefitted our survival in an ancestral environment. In the modern obesogenic environment – characterized by an abundance of easily accessible highly rewarding and palatable food – these ancient forces set the stage for overweight and chronic disease. We’ve created a world where we to a large extent have to actively oppose our own hard-wired instructions to achieve good health.

Reasons to live healthy in the modern world

Often, we hear that we live in a society where there’s too much focus on sex, body image, and “dieting”. However, what we have to remember is that the drive to “look good” is one of the major reasons people actually choose to eat healthy and exercise. There are definitely a lot of problems associated with the portrayals of “perfect” bodies in magazines, blogs, and social media, but what would have happened if we lived in a world where nobody cared about their bodily appearance? The desire to “look good” is probably what keeps many of our species from just settling down into the couch “for good”. Reducing the risk of chronic disease, getting acceptance by peers, and/or improving athletic performance are other important reasons many people choose a healthy lifestyle, but for many, these things come in second to aesthetic goals.

So, while the greatest incentive to move your body in the paleolithic era was to get food, build shelter, and survive, the reasons we move today are often more related to the feeling we get from exercising or the health/fitness-goals we have. These are clearly not as powerful motivators as the need for survival, but with a little willpower and discipline added in, perhaps our inborn instincts to relax and eat calorie-dense, palatable food don’t stand a chance?

Finding a balance

We have created a world where we can choose an extremely “comfortable” way of living. However, what I’ve learned is that although giving in to immediate desires might give short-term pleasure, the long-term benefits of the “healthy route” are usually (perhaps always) better. Let’s take fast food for example. For many, eating a calorie-dense, sugary doughnut from the bakery gives an immediate dopamine rush and feeling of pleasure, but soon thereafter, the rush is perhaps replaced by a major “sugar crash”. And as we all know, if you always choose the fast food route, illness and/or overweight will eventually follow.

I like to relax in my warm home and watch the latest episode of my favorite TV show in bed. However, I also want to be healthy, fit, and happy, and I know if I always choose the path of less resistance, I won’t be any of these things. So, I try to find a balance between choosing the “easy” path and the healthy path. It isn’t always straightforward, and I sometimes find myself wandering too much in either direction. During certain periods in my life, I’ve drifted towards a more “western lifestyle”, and what I’ve found is that it makes me miserable. However, the opposite can also be true. Many years back I had some periods where I was fanatical about health and fitness and followed a strict diet and exercise regimen to the letter. This definitely takes out some of the joy out of life…

There’s no doubt that to be healthy in a world filled with 7-elevens, escalators, and heating systems, we have to oppose some of the signals our body is giving us. Also, perhaps more importantly, we have to find ways to make exercise, healthy eating, etc. more desirable. One way is of course to set goals, thereby giving you a purpose with eating healthy and exercising beyond just the “good” feeling. Not everyone needs goals, but many (including myself) often do.

My two cents for getting more healthy behaviours into your life is to learn more about how different behaviours affect you, make plans and goals, and get into a routine!


  1. Nice!Keep up the good work.

  2. Good points. It can be hard to find a balance; what I find extremely difficult is blending with people who are not health conscience and don’t care that they eat GMOs, excessive sugar, etc. To those people I am *obsessive* however I have to do what works for me (who doesn’t want to feel good?!) and I cannot change (only hope to somewhat educate) others.

    True, I love my workouts because of the way they make me feel and I love being strong and looking fit. Reducing the risk of chronic disease (with traditional foods and exercise), improving athletic performance (for my own goals, not for competitions), and making up for past health mistakes are important to me but what prompted me to start dieting (which was a mistake) and exercising was in fact originally for aesthetic goals (as you stated).

    I’m glad more and more people are starting to learn what good health really means and how important real food is. For me I just wish it would catch more quickly to my crowd (family and friends)!

    I have learned from you that it is harder for some than others so I do the best I can to live and let live. It’s not always easy.

    • You’re right on the mark Jennifer. Can relate to everything you’re saying here.

      I think a lot of it comes back to what I discuss in the article. Ancient adaptations are still with us so there’s no surprise that so many people today eat a refined western diet and/or rarely exercise. Those who choose a healthy path have become a minority. Some of those who pay no interest to health/fitness have to “justify” their own behaviour by labelling the healthy folks as the weird and obsessive ones.


  1. […] The biological adaptations that have occurred since the agricultural revolution are just a drop in the pond compared to the profound changes to our living conditions during this time, and as a result we’re now experiencing a gene-environment mismatch (1, 2, 3). Suddenly, ancient genes that were adaptive in the past are setting us up for disease in the present by driving us to eat fast food and live a sedentary life. […]

Do you have any comments or questions pertaining to the article? If so, please feel free to post them below. Note: Comment moderation is in effect. Spam, rants, hateful remarks, etc. will be deleted.


Get every new post delivered to your Inbox

Join other followers: