Nutrition, Obesity, and Physical Activity

Nutrition, Obesity, And Physical Activity Nexus

The population of the United States is a much less healthy and fit than their preceding generations. Once the healthiest of modern societies, the U.S. has fallen below dozens of other nations in measures of the health of populations, including some countries whose progress into modernity was largely funded by the U.S. throughout the second half of the 20th century. Conversely, objective measurements of public health have declined in the U.S.

The British Healthcare system in Britain (in particular), has demonstrated that one of the most glaring weaknesses in the American healthcare system is the failure to appreciate the value of preventative care. Physicians and health insurance companies treat conditions mainly in relative isolation and frequently, only after they manifest themselves in symptoms of disease. Lifestyles issues that have a direct causal relationship to some of the most significant threats accounting for premature death from preventable disease are not addressed appropriately in relation to their potential harm to human health.

Nowhere is that more evident than in the dietary habits and patterns of physical activity in the American population. Approximately two-thirds of all adults and two fifths of all American children are either clinically overweight or obese, both of which are tremendous increases in only a few generations. The average American family eats at fast-food restaurants several times a week and consumes excessive amounts of sugar, fat, simple carbohydrates, and many more calories than advisable for good health on a constant basis.

In turn, the excessive caloric consumption and the inevitable weight gain in which it results for most people has been conclusively linked to serious and life-threatening (or shortening) medical conditions such as diabetes, high blood pressure, congestive heart failure, circulatory problems, arthritis, and various forms of cancer. The other principal component of issues responsible for the decline in human health in the U.S. population is an increasingly sedentary lifestyle and decreasing physical activity. Most adults do not exercise regularly and even children have become significantly less active than previous generations, substantially because of the ubiquitous influence of 24-hour cable television, computer video games, and the Internet.

These phenomena are hardly limited to the U.S.; in fact, there is empirical evidence documenting similar patterns and health-related issues throughout many of the wealthiest nations on earth. Ironically, in this respect, many so-called "Second-World" nations are healthier than some "First-World" nations, precisely because high per-capita national income is directly associated with increasing sedentary lifestyle and higher rates of consumption of highly processed or "gourmet" cuisine among wealthier populations. In every nation facing this issue, human health had been substantially compromised and on a large scale by the nexus connecting poor nutrition, obesity, and lack of physical exercise or activity to human health.

Methodology

To research the nexus between nutrition, obesity, and physical activity, the researcher conducted secondary research of each issue individually and also in various combinations. That research consisted of Online Internet searches of Google Scholar and two subscription-based research databases: highbeam.com and proquest.com. In addition to search terms such as "obesity," "fast food," "diabetes + diet," "obesity + health," "physical fitness + health," "physical activity + obesity," "nutrition + obesity," and "nutrition + health," that search also included the term "book review."

Academic textbooks and trade books identified in those searches were reviewed by the researcher in hard copy format in the public library and the university library, and in some cases, through the GoogleBooks application when relevant portions were available in their entirety online. The literature search was further broken down through search limiters into categories of peer-reviewed professional and academic resources and trade books and periodicals intended for mass consumption by laypeople. Editorials from non-authoritative sources within those resources were rejected but articles authored by accredited authoritative subject-matter experts were considered despite being published in non-professional and non-academic periodicals. Where searches generated newspaper articles, the references were considered in connection with the original referenced information or material when it was capable of being located through the described Internet search methodology.

The Conceptual Relevance of the Obesity Epidemic

In principle, obesity is a condition where the individual exceeds a body mass index (BMI) of 30, which corresponds to the relative proportion of body fat to non-fat tissue (Sizer & Whitney, 2003). Obesity has steadily increased in the United States since the middle of the 20th century (Desapriya, 2004). Currently, only two American states (Colorado and Washington, DC) have an obesity rate of less than one-fifth of their state's population. Thirty-three American states have a state population obesity rate of one-quarter, including nine states where approximately one-third of the entire state population is clinically obese (NIH, 2008).

In that regard, only a very small percentage of obesity is caused by disease; it is almost entirely the result of long-term lifestyle choices, particularly in connection with nutrition and physical exercise (Larson-Duyff, 2005). From a public health perspective, obesity is a tremendous health concern precisely because it is attributable to behavioral choices and because it is a known risk factor in so many serious human diseases responsible for preventable disability, waste of public funds and other resources necessary to treat those conditions, disabilities, and diseases, and because it is responsible for so much premature death in the human community (Larson-Duyff, 2005).

There are several specific reasons for this trend and it is equally evident in other countries, particularly those in which substantial relative wealth has combined with dramatic concurrent increases in sedentary lifestyles, especially since 1985 (NIH, 2008). Obesity has been implicated as a significant risk factor in the development of adult-onset (i.e. type-II) diabetes and is directly responsible for the dramatic rise in national rates of diabetes in the last twenty years in the U.S. (Larson-Duyff, 2005; Rinzler, 2004). Diabetes, in turn, accounts for significant incidence of disability and premature death; specifically, it causes blindness and organ failure as well as being responsible for multiple (and progressively more extensive) surgical amputations by virtue of loss of circulatory efficiency in the extremities.

Physiologically, chronically high blood sugar and lipid levels associated with unhealthful dietary habits that lead to obesity cause structural deterioration and weakening of capillaries and other blood vessels (Sizer & Whitney, 2003). That typically results in the partial occlusion, failure, and in the complete collapse of those blood vessels, severely reducing blood flow to the extremities. This prolonged compromise of circulatory efficiency causes necrosis of the tissue in the fingers, toes, hands, feet, and arms and legs, resulting in life-threatening gangrenous infections that require intervention in the form of surgical amputation. Similarly, this reduced circulatory efficiency also affects the tissues of the eye and typically causes blindness in untreated or unmanaged diabetics (Hamric, Spross, & Hanson, 2009; Taylor, Lillis, & LeMone, 2005).

Even more importantly, recent research has disclosed that diabetes is actually a direct cause of hepatic necrosis and renal failure, previously thought to be associated primarily with excessive consumption of alcohol and drug abuse, respectively (Hamric, Spross, & Hanson, 2009). In fact, the prolonged exposure of the liver (and kidneys) to high concentrations of blood sugar and lipids causes cellular damage that is comparable to that caused by alcohol and drug abuse (Sizer & Whitney, 2003).

Obesity is also a significant risk factor in several forms of cancer, particularly those occurring within the digestive tract (Hamric, Spross, & Hanson, 2009; Taylor, Lillis, & LeMone, 2005), as well as in arthritis. The link between obesity and arthritis is three-fold: first, excess body weight significantly increases the load borne by joints and connective tissues; second, that increased weight and the early symptoms of arthritis reduce the individual's physical activity even further because of physical discomfort associated with it; and third, the continual presence of high levels of blood sugar and lipids actually directly triggers inflammatory responses within the joints and connective soft tissues (Hamric, Spross, & Hanson, 2009; Taylor, Lillis, & LeMone, 2005).

In effect, obesity is both a direct and an indirect negative health factor because it is tremendously damaging to physiological tissues and essential life-sustaining physiological processes and it is also an indirect cause of other negative health factors, such as the reduction of physical activity as a self-protective mechanism against the discomfort associated with extensive or strenuous physical activity among those individuals who are significantly overweight. Unfortunately, to the extent weight loss is recognized as an important concern, it is much more in connection with for-profit exploitation of the problem through nationwide promotion of weight-loss products and fad diets (Lightsey, 2006; Sizer & Whitney, 2003). That industry accounts for billions of dollars in sales annually in the U.S. alone and, ironically, it often exacerbates obesity in many individuals over the long-term instead of helping them resolve their obesity issues (Lightsey, 2006; Sizer & Whitney, 2003).

Nutrition

By far, the primary cause of obesity, both in the U.S. And in other developed nations is the dramatic increase in processed foods heavily infused with large amounts of sugars and other sugar-like sweeteners, sodium, and fat (Larson-Duyff, 2005; Rinzler, 2004). In principle, excessive weight gain leading to obesity is a function of evolutionary mechanisms designed to allow early hominids (and many other living species) to take advantage of relative abundance of food sources as a safeguard against periods of relative scarcity of food resources. More specifically, when certain species (including homo Sapiens) consume more calories than necessary for immediate energy requirements, their digestive systems efficiently converts those excess calories into storable forms of reserve energy that are capable of being called upon in times of need (Larson-Duyff, 2005; Rinzler, 2004).

In humans, excess caloric consumption increases the amount of sugars dissolved in the blood (Larson-Duyff, 2005; Rinzler, 2004). This triggers a natural insulin response in which the pituitary signals the body to release extra insulin into the bloodstream to process the blood sugar. Many chronically overweight individuals become resistant to insulin, eventually requiring artificial insulin supplementation to maintain blood sugar levels consistent with ordinary physiological processes and to avoid onset of acute diabetic responses that are debilitating and that can be fatal when not treated appropriately (Hamric, Spross, & Hanson, 2009; Taylor, Lillis, & LeMone, 2005).

Even in non-diabetics, excess blood sugar attributable to consumption of more calories than necessary for energy production results in the storage of excess body fat through similar mechanism (Larson-Duyff, 2005; Rinzler, 2004). Ordinarily, blood sugar is converted by the liver into glycogen, which is stored both in the liver as well as in the muscle tissues where it can be called upon as a reserve energy source. However, once the body's glycogen storage has reached full capacity, additional consumption of calories triggers a longer-term storage mechanism whereby they are converted into body fat. This evolutionary adaptation was absolutely necessary for survival in evolutionary periods; today, however, it is no longer necessary in developed nations and it is the primary physiological mechanism responsible for obesity as a result of chronic overeating (Larson-Duyff, 2005; Rinzler, 2004).

Typically, the American diet consists of too many calories, too much dietary fat, too much high-calorie sugar and sugar-like sweeteners (such as high-fructose corn syrup), and too much sodium which also has detrimental effects on cardiovascular and cardiopulmonary health (Hamric, Spross, & Hanson, 2009; Taylor, Lillis, & LeMone, 2005). Excess dietary fat consumption is also a cause of excess cholesterol, another significant risk factor in the development of cardiopulmonary dysfunction by virtue of the reduction blood flow to the heart attributable to arterial plaque buildup within the walls of major blood vessels. It is also a cause of fatty tissue deposits on the major organ, including the heart, which only increases its load and its inefficiency as well (Hamric, Spross, & Hanson, 2009; Taylor, Lillis, & LeMone, 2005).

In terms of conversion to excessive body fat, certain foods are much more conducive to being converted into fat than others; unfortunately, they are also the very foods consumed most irresponsibly, simply because they happen to be the most palatable. Specifically, foods high in fat content are the most readily converted and stored from their nutrient state to body fat because they require the least energy input into breaking down their molecules and because they are already molecularly most similar to the composition of stored body fat (Larson-Duyff, 2005; Rinzler, 2004).

Sugars and simple carbohydrates (such as highly processed white rice, ordinary potatoes, and bleached white flours and grains) are also readily converted into blood sugar and then stored as body fat because their simple molecular structure requires comparatively little energy to break and convert into stored body fat (Larson-Duyff, 2005; Rinzler, 2004). Conversely, more complex carbohydrates (such as brown rice, sweet potatoes, and unbleached whole grain flours and grains) require significantly more energy to break their more complex molecules and they are more readily converted into glycogen than absorbed and converted into fat in the manner of simpler carbohydrates after being dumped into the bloodstream (Larson-Duyff, 2005; Rinzler, 2004).

Because food manufacturers always seek to generate the most revenue from their products, they have learned to rely heavily on the use of sugars, simple carbohydrates, and fats, simply because those foods are the most palatable to consumers and therefore, result in much greater sales than healthier foods that are not as satisfying (Lightsey, 2006; Sizer & Whitney, 2003). Fast foods are particularly notorious in that regard, especially in light of the degree to which and the manner in which they are marketed directly to children. Empirical evidence has established that children who become overweight or obese prior to adulthood have exceptionally high chances of remaining overweight or obese throughout their adult lives (Hamric, Spross, & Hanson, 2009; Taylor, Lillis, & LeMone, 2005).

Meanwhile, parents often express great frustration at the difficulty of limiting their children's consumption of fast foods for various reasons: many parents are so busy that they simply do not have the time to shop for fresh foods or to prepare more nutritious meals at home. In fact, in the U.S., more than two-thirds of families now spend more money on prepared foods (i.e. restaurant food) than they spend at the grocery store (Baldauf, 2008; Gibbs, 2007). Second, fast-food franchises are so ubiquitous and so heavily (and effectively) promoted and advertised that there is a significant peer-pressure factor that makes it even more difficult to steer children away from fast foods. Adults also develop nutritional habits that are highly detrimental to their health, often partly because of the convenience factor.

Unfortunately, the national epidemic of overweight and obesity has generated a multi-billion dollar weight loss product industry as well. That severely complicates the problems already faced by individuals who are overweight and obese, largely because it promotes unhealthy rapid weight loss over the short-term and through artificial means (such as fad diets) that cannot possibly be maintained over the long-term (Lightsey, 2006; Sizer & Whitney, 2003). In principle, losing excess weight and repeatedly regaining it is much more detrimental to long-term weight maintenance and health, primarily because this pattern of "yo-yo" weight loss actually increases the individual's percentage of body fat during each and every cycle of weight loss and regain (Lightsey, 2006; Sizer & Whitney, 2003).

The mechanism responsible for that phenomenon is very simple. First, virtually any means of drastically reducing caloric intake will result in dramatic weight loss (Larson-Duyff, 2005; Rinzler, 2004). However, no such diet that limits the individual to a very narrow range of foods or that entirely eliminates all carbohydrates (for one example of a popular diet fad called the Atkins Diet) can possibly be sustained for life. At most, such diets allow dieters to lose large amounts of weight and to keep it off for several weeks, months, or sometimes, several years, although even that is quite rare (Lightsey, 2006; Sizer & Whitney, 2003). In virtually one-hundred percent of cases, dieters who lose weight by these types of gimmicks always regain all of their weight within several years, and the vast majority of them do so much sooner, typically in less than one year (Lightsey, 2006; Sizer & Whitney, 2003)

The problem is that each and every time that they lose substantial amounts of body weight and then regain it, they actually increase their overall percentage of body fat (Lightsey, 2006; Sizer & Whitney, 2003). The reason is very simple: when body weight is lost quickly, it usually consists of roughly equal amounts of fat and non-fat body tissues (i.e. muscle tissue). Conversely, when body weight is gained quickly by overeating, it is almost entirely fat and not muscle or any other tissue. As a result, each time a dieter loses a given amount of weight quickly, he or she loses substantial amounts of non-fat tissue. Then, when the weigh is regained, it is almost all in fat. In effect, each cycle of rapid weight loss followed by its regain actually replaces some muscle tissue with body fat, thereby increasing the individual's overall body fat percentage in addition to merely regaining the amount of weight as measured in pounds (Lightsey, 2006; Sizer & Whitney, 2003). Ultimately, the continual increase in weight and in body fat percentage only further impedes the ability of the individual to participate in physically strenuous activity or exercise, which only contributes even more to the problem of obesity.