The Danger of “Healthy Eating,” Part II

The flexibility of human metabolism is an evolutionary adaptation, one that conferred longevity to individuals to withstand food shortages and thereby helped ensure the species' continued existence. In a relatively stable environment, survival of the individual depended on a combination of luck and beneficial genetic traits, but survival of a people relied on the traits alone. Only a catastrophic event could throw a species into instant turmoil. Natural disaster, a new, lethal disease or a more global phenomenon like an ice age might upend the order of daily existence. In those moments, a random genetic advantage, rather than a long-tested one, determined an individual's and even a species' fate. These monumental events were, in the past, always acts of nature. Never before have people been able to drastically change the environment enough to create our own cataclysm that directly challenges our built-in survival mechanisms. The unimaginable changes in food production and supply in recent decades has done exactly that. The world of feast and famine, deluge and drought no longer exists in the first world. Now, as if by a miracle of fate, we all live in a perpetual world of plenty. But our current good fortune is no stroke of luck at all; it's simply an advancement of civilization.

Since the start of the industrial revolution, human capacity and ingenuity have tackled one impossible dream after another: electricity, transportation, even space travel. One less celebrated triumph is in the agriculture and food industry. The impossible challenge was to feed an ever-increasing number of people. The explosion of the human population--recently surpassing seven billion and with no indication of slowing down--especially in the growing urban centers necessitated a grand revision of food production and distribution, at least in the prosperous first world countries. Agribusiness, large food conglomerates and national supermarket chains made feeding the growing population possible, and then some. America produces almost twice the needed per capita amount of food, measured in calories, the country needs. The application of efficient farming techniques, food manufacturing--largely from creative uses of corn--and innovation in food transport is a marvel of the past half-century. These industries, currently vilified for their complete disregard of the public health effects of their products, began with a more progressive motive, to supply affordable food to the masses, and have succeeded beyond anyone's wildest dreams. What is now commonplace in a supermarket--Chilean grapes, choice of any baked good and canned food that could feed a small army--was as unlikely as the fantasy world of 1984 only a few generations ago. Although the national debate over obesity has taken center stage, that's not a reason to ignore another achievement of industrialization.

Depressingly, the people enduring regular starvation--from sub-Saharan Africa to North Korea to those suffering from anorexia nervosa--have evolution on their side, not those who live in the land of plenty. The body has built-in mechanisms to survive long stretches with little food. Much as the electrical conduction system of the heart, the neural "wires" that produce each heartbeat, has several backup systems when the front line breaks down, digestion, metabolism and energy production can run on emergency as well. The eternally well-fed, if not overstuffed, have no such internal regulatory system to rely on. That's how a man-made life-changing event--limitless food supply--has overtaken our adaptive ability to cope. The premise that humans can override our instinctive reaction to food has proven largely to be false, as the sharp increase in childhood obesity and eating disorders can attest. Our internal food and weight regulatory system is thoroughly confused by the interminable excess food intake and availability. The physical effects in just a few decades, to both young and old, act like our own self-inflicted catastrophic event. A system that once ensured human survival now threatens our health and well-being. The easiest way to understand how the system has gone awry is through the adaptive, and maladaptive, ways our body reacts insulin.

Insulin is a hormone that regulates the transfer of energy from the blood supply to the rest of the human body. Food first needs to be digested in the stomach and then absorbed from the stomach and small intestines into the blood supply. After that, it's up to the endocrine system, primarily insulin, to distribute the energy to different parts of the body, to short-term storage--an easily accessible carbohydrate called glycogen--or to long-term storage, fat. In the normal ebb and flow of feast and famine, this regulatory system worked beautifully. The body monitored both energy needs and food intake, and the endocrine system released insulin to maximize the health and longevity of the body through lean and plentiful periods. Weight and metabolism, variables modulated by the endocrine system to maintain health, shifted accordingly. Most importantly, they are not end points but flexible components that fluctuate with the body's needs, not at one's will.

With the advent of limitless food supply, the well-honed system has gone awry, and the rise of childhood diabetes is a case in point. A generation ago, childhood diabetes, caused only by the inability to produce insulin, was to be differentiated from adult-onset diabetes, caused by insulin resistance-- slowed or limited reaction to the release of insulin--an effect of age, or more often weight gain. The public health problem of overweight children has made this nomenclature obsolete. Diabetes is now separated into type I, no insulin production, and type II, insulin resistance, and the unfathomable diagnosis of type II diabetes in children, with the same treatment and long term medical outcomes as in adults, including amputation and kidney failure, is now run of the mill.

What has condemned so many children to the early fate of an adult, debilitating disease is the world of plenty. Left to fend for themselves among the fast food chains, ever-present snacks and vending machines at school, children take in much more food than their bodies need. A child's metabolism no longer faces times of famine or drought, so, exposed to the inability of human metabolism to compensate for persistent, increased food intake, the inevitable cycle of weight gain and overeating continues. As in older adults, obesity, in those susceptible, triggers the onset of type II diabetes. Metabolism could rise, fullness could be triggered more quickly, hunger could wane, but the endocrine system doesn't work that way, for coping with a land of plenty never happened before. Nothing stops the overweight, diabetic child from continuing to eat. No such evolutionary adaptation exists. 

The rise of eating disorders--as a general phenomenon, rather than the suffering of one individual--is a different but equally maladaptive response to a world of plenty. Although the ideal female form has, in previous times, been very thin, never before has the entirety of a population encountered this desired body shape and the world of plenty simultaneously. The push-pull of willful food restriction and limitless supply of any food imaginable has tested the human food regulatory mechanism and exposed its weaknesses. The response to starvation, namely slowed metabolism followed by obsessive hunger, is a powerful evolutionary adaptation and almost always wins. The end result, for the majority of dieters and people with eating disorders, is periods of overeating or binging. Repeated attempts to starve only strengthens these internal responses. Surprisingly, years of restricting food intake, even when interrupted by bouts of overrating, affects the body similarly to the overweight who have type II diabetes: their bodies become resistant to insulin. In this case, the body refuses to increase metabolism after years of starvation and instead puts extra food intake into deep storage. Metabolism, and therefore insulin effectiveness, rises only after an extended period of regular food intake. Becoming immune to insulin and storing extra food as fat seems to be the only default reaction to eating patterns outside the norm. In today's world of plenty, it is highly ineffective.

The Dangers of "Healthy Eating," Part I

Just walk through any main street, from the small country town to the big city, and it is evident that we have much, much more food than we could ever consume. The number of fast food outlets, convenience stores and supermarkets seems unlimited. The edible food waste of the First world could feed most, if not all, of the world's starving people.

But the larger realities don't change how each individual, still charged with feeding oneself, thinks about food. The now mundane choice, and for some the burden, of what to have for lunch among the wide options would have been a dream come true for humans through the ages. It is as if we have all become the wealthiest aristocrat with more food than we could ever consume, with every possible treat at our disposal. Yet this purported boondoggle turned out to be much more problematic than anyone could have guessed. Rather than creating a utopia, the world of plentiful food has left millions of people reeling without the ability to handle a seemingly basic fact of life, how to eat.

We are a species designed to live in a land with the natural ebb and flow of feast and famine, not in food heaven. A basic fact of human life for almost our entire existence, the worry of going hungry isn't relevant for an astounding number of people in modern life. The preponderance of food tempting our palate at every turn has completely perplexed our internal ability to regulate hunger and meals. Humans have been engineered to outlast famine and drought but have no clue what to do with an endless surplus. The newfangled coping mechanisms--ranging from arbitrary food rules to diets and, in more extreme cases, from eating disorders to Bariatric surgery--only highlight the futility of trying to outwit our fundamental instinct to eat to survive. But it is the least controversial and most widely accepted solution that confuses us the most. The next series of posts will address the effects of this insidious cultural innovation: the concept of "healthy eating."

In order to understand what's so ineffective about the concept of healthy eating, it helps to start with the current fascination with the human brain. The increasing knowledge about human's higher order functioning, such as consciousness and planning, mental constructs unique to people, has seeped into the mainstream. The unfortunate result is the expectation that people can think and reason their way out of any situation. When it comes to food, it is necessary to remember we have evolved from the same genetic line as apes and other mammals so the basest instincts apply.

Humans, like all animals, value survival of the species above all else. Enduring times of famine and drought was and still remains essential. Just as bears hibernate or squirrels store acorns for the winter months, people developed evolutionary adaptations, mainly an adjustable human metabolism and hunger drive, to weather more challenging circumstances. And that ability to survive, despite the creation of a world of plenty, trumps any intellectual means to manage food. Put simply, when it comes to food, basic drives override rational strategies. It is instructive to take a look at the basic biological reaction to times of need and times of plenty. An often used but misunderstood concept, metabolism, the utilization and dispensation of energy throughout the body, is the central tool to adjust to an ever-changing food supply.

A withering food supply triggers a cascade of physical changes: slowed non-essential body function, more efficient use of energy, steady breakdown of the body's energy stores and any extra food intake going directly to temporary storage. The swift transition in metabolism when times became lean is a key component to our longevity, otherwise humans would have become extinct many ages ago. The ability to survive famine is a trait deeply embedded in our genetic make-up. In other words, our bodies are built to survive starvation.

The same cannot be said about times of plentiful food. Those periods were, from an evolutionary perspective, mere blips in the calendar. The boom of a large food supply would never threaten humans with extinction so any adaptations are short-lived and limited in scope. In fact, these brief periods of plenty were, if anything, used to protect against the inevitable hungry times in the near future. Consequently, these were times of brief gorges while those more prone to restraint encouraged the tribe to consider external food storage, say for the upcoming winter, rather than rely solely on humans' internal ability to store energy.

After an extended period of overeating, the body will work hard to overcome the excess. Although the metabolic changes are the opposite of the starvation response, sped up metabolism and increased energy usage, the process is much less robust, and the body is willing to give up quickly and just store the energy as fat, fully expecting to need the backup shortly. 

Stay tuned for part II.