In my many years of creating and testing a wide variety of health lifestyle interventions, I’ve discovered that there are two over-arching reasons why people fail in their attempts to improve their health practices. First, they underestimate the power of the forces arrayed against them, forces that are environmentally ubiquitous and rooted deeply in our evolutionary history. And second, they too often fall for the latest gimmick – the fad diet, the magic supplement – seemingly unaware of the potent behavioral strategies that have been shown effective in scores of studies. For this blog we will first take a look at the powerful forces arrayed against you; later we will discuss how you can arm yourself with the best weapons available to counter these forces.
The formidable forces confronting us in our quest for healthy living combine a millennia-in-the-making physiology built for times of scarcity and challenge with an industrialized environment of abundance and comfort – a mismatch that works relentlessly to undermine the healthy life.
It’s an unfortunate irony that the evolutionary processes that developed a brain capable of creating a Shakespeare sonnet and a Watson computer have not prepared us for healthful living in the 21st century. Although modern man (Homo Sapiens Sapiens) has only been around for 50,000-60,000 years, the genetic basis for our eating habits and other health practices has been forming for well over a million years, as we evolved from Homo Habilis in the Pleistocene period about 2 million years ago, through Homo erectus to modern humans. Dr. Bruce King at Clemson University has recently conducted an analysis of these evolutionary roots, with fascinating though sobering findings. Although they were omnivores, eating both plants and meat as a survival mechanism, prehistoric humans almost certainly consumed as much animal fat and carbohydrates as possible when those food were available. Moreover, it is likely that the ancestral brain (probably cortico-limbic pathways) evolved to signal preference for high-fat and high-carbohydrate foods, leaving modern humans with a gastrointestinal system and brain circuitry that favors the intake of nutritionally high-density foods. And unfortunately, these particular brain reward systems are driven less by physiological hunger signals than by the palatability of foods – their taste, smell, and texture. Indeed, it seems clear that we are hard wired to seek out highly palatable, pleasant tasting foods that are typically high in fats, salt and sugar, and to continue to consume them long after any traces of hunger have disappeared.
As the hominid brain grew larger and more complex, evolution has left us with brain-driven food preferences that are ill-suited to an environment with an abundance of high density foods. And because these powerful brain reward systems are not self correcting (non-homeostatic), they make it very difficult to resist over-consuming when presented with the modern cornucopia of pleasant tasting foods and drinks.
Our ancestors seldom had to worry about over-consuming and obesity-related diseases, not only because high density foods were hard to come by, but because they had to track down and kill what they ate – not very conducive to a sedentary lifestyle. Paul Salopek, who is currently tracing (on foot) the pathways of the humans who colonized the planet some 60,000 years ago, reports that men of the present-day Hadza people of Tanzania (among the last hunter-gatherers left on earth) walk on average seven miles a day in pursuit of game (women somewhat less). It is likely that through thousands of years our bodies evolved to support substantial amounts of daily physical activity – bodies that are now typically seated for most of the day, gazing at papers and electronic screens.
Complementing the evolution-based preferences toward unhealthy dietary practices is the post-industrial environment that provides us with unparalleled comfort and pleasure -- and can be very hazardous to our health. In the last two centuries science and engineering have given most of us in the industrialized west (and increasingly in the rapidly developing east) a life of ease and comfort our ancestors could scarcely dream of. Not only have advances in medicine and sanitation engineering nearly eradicated the plagues that in earlier generations cut like a scythe through entire populations; science and modern machinery have freed most of us from the arduous demands of physical labor and provided us with access to a rich abundance of foods. Though few of us would choose to go back to an earlier era of hardship and scarcity, there is most definitely a price to be paid – a Faustian bargain, so it would seem – for our enjoyment of these contemporary comforts.
For along with all these marvelous advances, modern life has also pushed us toward a lifestyle of poor dietary practices and slug-like inactivity. While serving up wondrous delights, the food industry is unquestionably exploitative, and cares little (not at all?) that so many of the foods they are manufacturing – especially the snacks and sugary drinks – are disease-inducing in all but the smallest of quantities. Legions of food scientists perfect foods that strike the “bliss point” in taste and texture so that you will not only find them irresistible, you will find them, in their uncanny combination of sugars, fats and salt, to be devilishly difficult not to over-consume. Too many busy families burdened with multiple jobs and kids’ activities find it convenient to forego actual meals with wholesome servings, relying instead on pre-prepared fast foods – or just grazing on manufactured snacks.
To make matters worse, the trend toward increased consumption of manufactured foods laden with sugars and fats has been accompanied by a growth in sedentary occupations that require no more physical exertion than a keystroke. And too often, the sedentary cubicle life is sandwiched between long commutes, leaving little time or energy (or inclination) for regular physical activity.
So these are the powerful, relentless forces you have to contend with: brain circuitry from another age pulling you toward unhealthy foods, a diabolically effective food industry eager to sell you those foods, and occupations and family life that foster poor eating habits and inactivity. If you’re going to have any chance of living a healthy lifestyle, you will need to arm yourself with the best available strategies – the evidence-based behavioral strategies that are discussed in my blog on Behavioral Strategies.