Feature
No.40
January 2004
 
    

The Challenge of Avoiding the Adverse Nutritional Impact of Globalization
Jonathan C. Reeser, MD, PhD, Marshfield Clinic, Marshfield, WI USA
Cynthia K. Reeser, MPH, RD, LD, George Washington University Medical Center, Washington, D.C. USA



The developed nations of the world are presently facing an obesity epidemic of staggering proportions. The adverse health consequences of overnutrition and malnutrition represent a matter of serious concern not only to those populations directly affected, but also to those living in developing countries to which these problems are being insidiously exported.
That nutrition plays an essential role in the maintenance of human health and well-being is well understood. There is ample scientific evidence to suggest that diet and nutritional status have a tremendous impact on an individual’s relative risk of developing numerous non-communicable diseases, including hypertension, heart disease, non-insulin dependent diabetes, breast and colon cancer, obesity and osteoporosis. The World Health Organization (WHO) has asserted that the underlying determinants of these non-communicable diseases are largely the same world-wide, and include (1) increased consumption of energy-dense, nutrient-poor foods that are high in fat, sugar and salt, and (2) reduced levels of physical activity.
In addition to the effect of diet on individual wellness, population health parameters are significantly influenced by cultural dietary practices. National and regional traditions and customs, along with religious tenets and political motives and initiatives all impact how, what, why and even when we eat - both individually and collectively. Studies have demonstrated that the interaction of cultural dietary habits with a population’s genetic predisposition strongly influences population health. However, with the inexorable dissemination of economic entities and cultural practices from industrialized nations to the developing world (a process that has come to be known as “globalization”), such epidemiologic diversity of diet and disease is becoming increasingly rare. The eating patterns of developed nations are progressively being adopted throughout the developing world, with predictably adverse public health consequences. Of particular concern are the increasingly unhealthy diets and reduced physical activity patterns of children and adolescents. Indeed, the WHO 2002 World Health Report observed that the burden of morbidity and disability attributable to non-communicable diseases now weighs heaviest in the developing countries, where those affected are (on average) younger than in the developed world.
Many nations throughout the world are now confronted with rapidly escalating rates of obesity. Nowhere is the problem more dire than in the USA, where more than 60% of adults and 25% of children are either obese (Body Mass Index [BMI] = 30) or overweight. In 1991, only four of America's 50 states claimed a prevalence of obesity in excess of 15%. Today, at least 37 states have rates exceeding 15%. Between 1960 and 2000, the prevalence of obesity among adults aged 20 to 74 years in the United States increased from 13.4% to 30.9%. An estimated 325000 deaths and 4.3% to 5.7% of direct health care costs (approximately US $39 to $59 billion annually) are attributed to obesity. Childhood obesity has reached epidemic proportions. Some 4.7 million youth 6 to 17 years of age are overweight or obese. The number of overweight youth has more than doubled over the past thirty years. From a public health perspective, obesity ranks second only to smoking as a cause of non-communicable diseases and associated mortality in the US.
The dramatic surge in obesity has paralleled the global increase in consumption of foods from "fast food" franchises. These foods are not only "engineered" to be higher in fat and refined carbohydrates than the less processed and refined "traditional" foods that they ultimately replace, but are also typically served in "super-sized" portions that dramatically exceed the caloric needs of the average individual. Although the McDonald’s restaurant chain has frequently been targeted by the opponents of economic globalization as emblematic of the problems that have accompanied the phenomenon, McDonald’s is only one of many fast food restaurants clamoring for our business through omni-present advertising. Born in post-World War II America, the “fast food” industry now carries almost unimaginable economic clout - to say nothing of its effect on the health of the industrialized world. In his book “Fast Food Nation”, Eric Schlosser chronicles the history of the fast food segment of the American economy. Schlosser reports that whereas in 1970 Americans spent roughly $6 billion on “fast food”, in 2000 they spent in excess of 110 billion dollars - more than was spent on movies, books, magazines, newspapers, videos and recorded music combined. In this new millennium, nearly 25% of the adult population in the United States consumes fast food on any given day. Globalization has permitted the metastasis of the fast food culture, with its attendant health sequelae. As a case in point, between1984 and 1993 the number of fast food restaurants in Great Britain doubled - as did the prevalence of obesity among adults.
The growing “fast food” culture of industrialized societies is symptomatic of a broader, evolving cultural phenomenon that discourages individual responsibility and control over the quantity and quality of foods consumed. Some of the trends that contribute to this problem include:
  • reduced frequency of meals eaten at home with family members
  • increased frequency of foods prepared outside the home and/or eaten “on the go”
  • the super-sizing of portions, fueled by the consumer's perception of optimum value for their food dollar
  • increased intake of energy-dense, processed, and refined convenience foods that often contain high fructose corn syrup, partially hydrogenated fats, and/or refined grains, and are low in micronutrient density
  • increased food consumption between meals, associated with leisure pursuits, entertainment, comfort, and stress
  • reduced intake of fruits, vegetables, whole grains, and legumes
  • increased availability of low nutrition snacks and drinks from vending machines in schools
  • powerful media influences and social norms that create a seductive marketplace encouraging consumption of convenience foods
It is a common misconception that affluence is a precondition for obesity. Rather, malnutrition and obesity often afflict low-income households through a phenomenon known as “food insecurity”, in which relatively inexpensive foods that are filling but also high in fat, sugar, and calories are purchased in an effort to maintain a sense of satiety. Unfortunately, these foods are nutritionally depleted, and offer the unsuspecting consumer a false sense of nutritional security. According to a recent WHO report, the impact of a diet high in energy-dense refined foods on world population health is being most significantly felt in developing countries, where it may be contributing to both the economic and social stratification of those societies.
Perhaps the segment of the population most dramatically affected by the observed shift in the global dietary paradigm is the world’s youth. The incidence of glycemic dyscontrol among the youth of the industrialized world is skyrocketing. The increased incidence of diabetes mellitus among this demographic is without doubt also related to the burgeoning obesity crisis. The long-term health implications and societal cost of this epidemic of obesity and nutritional decline therefore will probably not be understood or fully appreciated for years to come. However, one probable consequence of the global shift in dietary patterns that is already apparent is the so-called “metabolic syndrome”. Characterized by obesity and systemic inflammation, the metabolic syndrome is also defined by elevated triglycerides, reduced high density lipoprotein, elevated blood pressure, and fasting hyperglycemia. Studies have reported an age-adjusted prevalence of 23.7% among adults living in the United States, while 4% of US adolescents are thought to have this condition. The prevalence of the metabolic syndrome increases to nearly 29% among adolescents who are significantly overweight (defined as youth aged 12 - 19 with a BMI=95%ile).
Where should we look for solutions to this burgeoning and worrisome public health problem? The "cure" for obesity appears as elusive as ever. Energy balance may be defined as the difference between the number of calories consumed and the number of calories expended. If an individual maintains a negative energy balance, over time they will lose weight. Conversely, an individual in positive energy balance (in which caloric intake consistently exceeds caloric expenditure) will gain weight. As human beings, our body chemistry is programmed to store excess calories in “banks” of adipose tissue, from where it may be mobilized in times of need. Increasingly, the need to draw upon these important energy reserves is becoming more and more rare, since food is not only more abundant but we expend less energy by virtue of increasingly sedentary lifestyles. As caloric intake has risen, caloric expenditure from activity and exercise has steadily declined. Close to 60% of Americans exercise rarely or not at all. Children who watch more than 5 hours of television a day are five times as likely to be overweight than children who watch less than 2 hours a day. Only 25% of young Americans ages 12-21 years participate in light to moderate activity daily. Industrialization, modernization, and urbanization are all suspected of contributing to this insidious and progressive lack of physical activity which contributes as much to the high prevalence of overweight and obesity as unhealthy eating behavior.
The United States Federal Government, along with many other organizations including the American College of Sports Medicine, has published recommended “aerobic exercise guidelines” designed to help educate the general public regarding the need for and the benefits of regular exercise. In general, exercise should be performed no less than three to five times per week. Endurance exercise performed within the aerobic range is felt to be most effective at “burning” fat, but all activity should be considered to be beneficial and therefore encouraged. Walking, climbing stairs, and other activities of daily living have cumulative effects on caloric expenditure that over time may significantly shift an individual’s energy balance towards weight loss. The ACSM recommends that “if weight loss is the major goal, participate in your aerobic activity at least 30 minutes for five days each week”(Fig 1).
Figure 1

Recognizing the importance of exercise in the weight loss equation does not mean, however, that we should ignore the role of diet in maintaining energy balance. The amount of caloric energy required by humans varies based on a number of factors including genetics, gender, health status, metabolic demands, climate, body weight, and stress. Estimates of the minimum daily caloric requirement vary, but it is generally agreed that the average person in the richest countries consumes 30-40% more calories than is needed, while people in poorer countries typically consume 10% fewer calories than is considered optimal. In addition to balancing one’s individual energy equation, macronutrient consumption should fall within recommended guidelines. The Institute of Medicine’s Acceptable Macronutrient Distribution Range (AMDR) for adults is expressed in terms of percentage of total energy intake: 45 to 65% carbohydrates, 20 to 35% fat; and 10 to 35% protein. The AMDR for children ages 4 to 18 years is 45-65% carbohydrate, 25-35% fat and10-30% protein. Obviously, tremendous dietary diversity is possible within these stated ranges, and further research is needed to link specific intakes to optimum health outcomes.
With so many dietary choices to make, it is natural to ask “what diet is best?” The answer to this question requires a reductionist view that may not be entirely appropriate on a population basis. Indeed, a single “best” diet may be unreasonable to prescribe since there are undoubtedly genetic differences between (and even within) various populations and cultures. For instance, Native Americans have been found to have a high prevalence of the so-called “thrifty gene” that predisposes individuals to deposition of body fat stores, and may trigger an obese phenotype if the individual is exposed to a diet high in refined foods. Furthermore, a diet that promotes weight loss may not be the best diet for long-term health maintenance. Nevertheless, it seems reasonable to conclude that the “proper” diet should at a minimum take into account existing or known health conditions (diabetes, cardiovascular disease, dyslipidemia, chronic illness) and the baseline energy expenditure of the individual. For example, athletes require more calories per day than do non-athletes in order to maintain proper energy balance. The sport in which one participates should also influence dietary choices, since diet can affect the availability of energy stores during training and competition.
While a review of the biochemistry and physiology of energy substrate utilization is beyond the scope of this article, it is instructive to recall that while the human body is capable of utilizing a variety of substrates for energy production, the preferred sources of energy are carbohydrates and fats. This is reflected in our body’s intrinsic energy storage mechanisms. Carbohydrate in the form of glucose (or stored as glycogen) is the body’s preferred and most readily accessible source of energy. However, an average individual has sufficient stores for only 90-100 minutes of exercise. Fats, on the other hand, are not only a more energy-rich storage medium (releasing 37 kJ per gram compared to 16 kJ per gram for carbohydrate) but may also be found in significantly greater abundance than carbohydrate stores: the average human has sufficient fat stores to (in theory) support up to 80 hours of exercise. Note that protein, while in abundant supply, is an inefficient source of energy and is the body’s least preferred energy source. These observations form the basis for the popular low carbohydrate diets (eg the Atkins Diet and the South Beach Diet). A great debate is currently waging about the relative merits of these high protein, high fat, low carbohydrate diets. Advocates claim that diets high in protein and lower in carbohydrate promote metabolism of adipose tissue in the relative absence of preferred energy-rich carbohydrate and result in rapid weight loss without significant adverse effects. Long term studies have not been conducted to confirm this claim, however, and numerous professional organizations such as the American Dietetic Association and the American Heart Association have cautioned against such diets out of concern over possible adverse affects on serum lipids, insulin and liver and kidney function.
If, as suggested, the “fast food culture” plays a considerable role in the world-wide obesity epidemic, it seems appropriate to ask whether modifying our food culture might reverse the process. While the answer to this question may be ultimately unknowable, such thinking forms the foundation of a relatively recent world-wide cultural movement known as “Slow Food”. The Slow Food movement seeks to restore the “kitchen and the table as centers of pleasure, culture, and community” by promoting sustainable stewardship of the land and ecologically sound food production, renewal of culinary traditions, and a return to a “slower and more harmonious rhythm of life”. In essence, Slow Food is the antithesis of fast food and dietary globalization. The Slow Food movement was born in Italy in 1986; the international organization was established in Paris in 1989. The movement encourages members (who number approximately 75000 world-wide) to support local growers and like-minded businesses rather than rely on industrial growers or large scale distributors/retailers. Although a relatively small organization in the United States, with only 12,500 members, the movement appears to be having an impact: many fast food chains are adding “healthy” menu choices in an effort to retain the business of these typically affluent and influential clients.
Despite the apparent promise of the Slow Food movement, it is nevertheless evident that dieting alone is rarely sufficient to lose weight: 95% of Americans who attempt to lose weight solely by restricting calories fail. Not surprisingly, as a result of the predictable failure of diet alone to result in significant weight loss, there has been an increased interest in surgical beautification and weight loss procedures, ranging from gastric bypass (bariatric) surgery to liposuction. At the end of the day, however, there is no substitute for increasing the number of calories expended. The most convenient and effective means of “burning” calories is exercise, as discussed above. Not only does aerobic exercise shift the energy balance toward weight loss, but it bestows other physiologic and psychological benefits that are conducive to health, including lower blood pressure, improved glycemic control, and improved self-image.
The trend towards global obesity is a broad spectrum, multifactorial problem. Solutions will undoubtedly require a transdisciplinary approach. Nutritionists, dietitians, public health workers and governmental officials, health care professionals, teachers, parents, city planners and international organizations such as ICSSPE must work collaboratively to devise integrated community-based programs that promote and encourage activity, exercise, and responsible nutrition. If we are to reverse the existing trends, future behavioral interventions should target the youth. Existing research into the barriers that prevent children and adolescents from eating healthfully and exercising regularly suggests that such efforts must address the social and environmental influences on dietary practices and exercise, including (but not limited to) parents, teachers, schools and care-givers. Educational offerings should include instruction in nutrition, time-management, self-motivation, and sound decision-making skills. School curricula and community programs should promote and, indeed, reward physical activity and exercise. Over time such programmatic initiatives may help foster positive, healthy lifestyles. Equally importantly, such programs may eventually bring economic pressure for reform to bear on the institutions that have contributed to the demise of cultural dietary diversity through the process of globalization. Although the challenge ahead is clearly enormous, to do less invites certain failure.

Bibliography
American DieteticAssociation: Position of the American Dietetic Association, Society for Nutrition Education and American School Food Service Association. Nutrition Services: An Essential Component of Comprehensive School Health Programs. JADA 2003; 103:505-514.
Bravata D, et al. Efficacy and Safety of Low Carbohydrate Diets. A Systematic Review. JAMA 2003; 289:1837-1850.
Bray GA, Popkin BM. Dietary fat intake does affect obesity! Am J Clin Nutr 1998. 68:1157-1173.
Centers for Disease Control and Prevention. Guidelines for School Health Programs to Promote Lifelong Healthy Eating, US Dept. of HHS. MMWR. 1996;45(RR-9): 1-41.
Centers for Disease Control and Prevention. Guidelines for School and Community Programs to Promote Lifelong Physical Activity amond Young People. MMWR. March 1997;46(RR-6): 1-36.
Cook, S, et al (2003) Prevalence of a metabolic syndrome phenotype in adolescents. Arch Pediatr Adolesc Med 157 (8) 821-7.
Flegal KM, Carroll MD, Kucsmarski RJ, Johnson CL. Overweight and Obesity in the United States: Prevalence and Trends. 1960-1994. Int J Obes Relat Metab Disord. 1998;22:39-47.
Flegal KM, Carroll MD, Ogden CL. Prevalence and trends in obesity among US adults, 1999-2000. JAMA. 2002;288:1723-1727.
Ford, ES, Giles, WH, and Dietz, WH. (2002) Prevalence of the Metabolic Syndrome Among US Adults. JAMA 287 (3) 356-9.
Gleason P, Suitor C. US Dept. of Agriculture. Food and Nutrition Service. Nutrition and Evaluation, changes in children's diets: 1989-1991 to 1994-1996. CN-01-CD2. Alexandria, VA. Office of Analysis. 2001.
Institute of Medicine of the National Academies. Dietary Reference Intakes. The National Academies Press. Pre-publication copy, unedited proofs. Washington, DC., 2002.
Integrated prevention of noncommunicable diseases. Draft global strategy on diet, physical activity and health. World Health Organization. 27 Nov 2003. Geneva.
Joint Position Statement of the American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada (2000) Nutrition and Athletic Performance. Med Sci Sports Exerc 32 (12) : 2130-2145.
Ludwig D, Peterson K, Gortmkaker S. Relationship between consumption of sugar sweetened drinks and childhood obesity: A prospective, observational analysis. Lancet. 2001;358:505-508.
Maughan, R.J. (ed) Nutrition in Sport. Blackwell Publishing. Oxford 2000
Mokdad AH, Serdula MK, Dietz WH, Bowman BA, Marko JS, Koplan JP. The spread of the obesity epidemic in the United States 1991-1998. JAMA. 1999; 282:1519-1522.
Neumark-Sztainer D, Story M, Perry C, Casey MA. Factors influencing food choices of adolescents: Findings from focus group discussions with adolescents. JADA 1999;99:929-934, 937.
O'Dea JA. Why do kids eat healthful food? Perceived benefits of and barriers to healthful eating and physical activity among children and adolescents. JADA 2003;103:4, 497-500.
Schlosser, E. Fast Food Nation. Houghton Mifflin. Boston 2001.
Troiano RP, Flegal KM. Overweight children and adolescents. Description, epidemiology and demographics. Pediatrics. 1998;101:497-504.
Willet WC. Is dietary fat a major determinant of body fat? Am J Clin Nutr 1998;67:556S-562S.
World Health Organization. The World Health Report 2002: Reducing risks, promoting health life. Geneva 2002.


Jonathan C. Reeser, MD, PhD,
Marshfield Clinic
1000 North Oak Avenue
54449 Marshfield, WI USA
jreeser@charter.net



http://www.icsspe.org/portal/bulletin-january2004.htm