Overweight and Obesity Epidemic in America – Part VI: Modifiable Risk Factors

Suggested Citation: Garko, M.G. (2011, March). Overweight and obesity in America – Part VI: Modifiable Risk Factors. Health and Wellbeing Monthly. Retrieved (insert month, day, year), from www.letstalknutrition.com.

Overweight and Obesity Epidemic in America – Part VI: Modifiable Risk Factors

Michael G. Garko, Ph.D.

Host – Let’s Talk Nutrition

Introduction

Stunningly, an estimated 68% of adults in the United States aged 20 and older are either overweight (34.2%) or obese (33.8%). Only 31.8% of adults in America aged 20 and older are at a healthy weight. Seventeen percent of U.S. children and adolescents aged 2-19 years are obese. Nearly one third of children in the United States are currently either overweight or obese with BMI levels ≥ 85th percentile. This represents a tripling of overweight and obesity prevalence among children since 1980 (see Ogden & Carroll, 2010).

More than a few experts have weighed-in (no pun intended) on exactly how America became an obesogenic society. In terms of the obesity epidemic plaguing America, “Everyone and everything has been blamed for its cause: school meals, processed food, fast food, beverages, fat, sugar, working parent, you name it” (Ayoob, 2010).

The March, 2011 issue of Health and Wellbeing Monthly (HWM) will not attempt to focus on “everyone” and “everything” responsible for the overweight and obesity epidemic in America. Rather, attention will be devoted to modifiable risk factors associated with one of the most serious public health threats to American adults and children in the 21st century.

Overweight and Obesity Defined

The term “overweight” refers to an excessive amount of body weight, which can be constituted of muscle tissue, bone, adipose or fat tissue and water, while the term “obesity” refers to an excessive amount of adipose or fat tissue (see National Institute of Diabetes and Digestive and Kidney Diseases, 2010).

Body Mass Index (BMI) is used to measure the amount of body fat/adipose tissue based on a person’s height and weight. Specifically, BMI is expressed as a person’s weight in kilograms divided by height in meters squared (kg/m2). Individuals with a BMI of 25.0-29.9 are classified as being overweight, while those with a BMI of 30 or more are classified as obese and those with a BMI more than or equal to 40.0 are classified as extremely obese (see Ogden and Carroll, 2010).

Multi-factorial and Interactional

Overweight and obesity are not associated with or caused by a single variable. Rather, they are multi-factorial in nature. The research on overweight and obesity provides convincing evidence that they result from a complex of interacting traits, acquired conditions and lifestyle variables that implicate various environmental, behavioral, psychological, physiological, social and genetic factors.

Some risk factors are described in the literature as being independent (e.g., overeating) because they have the potential to bring about overweight or obesity single-handedly. However, risk factors and causes can and most often interact and work together with one another to create a greater likelihood of becoming overweight or obese and have a greater deleterious impact on health. It stands to reason that the more risk factors and causes an individual possesses for obesity the greater the chances of that person developing and dying from it.

Risk Factors[1]

Risk factors are variables possessing the potential to increase the likelihood of developing a particular disease or health condition (e.g., overweight or obesity). They are linked to a disease or health condition by means of a statistical association or correlation. The stronger the statistical association is the stronger the inference that can be made about a particular factor putting a person at risk for becoming obese.

It is important to understand that while a particular risk factor or set of risk factors increases the likelihood of becoming overweight or obese, this does not mean that there is a certainty suffering from either condition (see Black, 1993).

In contrast to a risk factor, a cause is “that which produces or effects a result; that from which anything proceeds, and without which it would not exist” (Webster’s Online Dictionary, 2010). Thus, causes of obesity are definitive in producing it.

Modifiable Risk Factors Related To Overweight and Obesity

Imbalance Between Consumption and Expenditure of Calories.

At its most fundamental bio-physiological level, the immediate cause of overweight and obesity is an imbalance between the amount of calories consumed from food and drink with the number of calories expended or otherwise burned as body fuel. That being said, there is a constellation of nutritional, genetic, physiological, behavioral, psycho-social and cultural-societal reasons why the imbalance occurs leading to humans becoming overweight or obese.

Principle of balancing calories-in and calories-out. At the end of the nutritional day, preventing overweight or obesity becomes balancing the number of calories consumed each day with the number of calories expended either through physical activity and the various energy-requiring physiological processes and functions of the body. The following graphic provided by the Centers for Disease Control and Prevention (2010) is useful in explaining the principle of balancing calories:

If you are… Your caloric balance status is…
Maintaining your weight in balance.” You are eating roughly the same number of calories that your body is using. Your weight will remain stable.
Gaining weight in caloric excess.” You are eating more calories than your body is using. You will store these extra calories as fat and you’ll gain weight.
Losing weight in caloric deficit.” You are eating fewer calories than you are using. Your body is pulling from its fat storage cells for energy, so your weight is decreasing.

The myth of getting fat from eating fat. A common myth is that only eating fat will make a person fat. Excess calories can come from an overconsumption of carbohydrates, fats or protein and will be stored as fat tissue, no matter their macronutrient origin. It is also worth mentioning that one pound of body fat is equivalent to 3500 calories. If you were interested in losing one pound of fat in a week, then you would have to burn 3500 calories more than what you typically consume in seven days. In other words, you would need to have a calorie deficit of 3500 calories. The calorie deficit can be created in just three ways: 1. Decrease daily food intake, 2. Increase daily physical activity or 3. Practice a combination of both.

Sedentary Life Style

Contributing to the creation of our obesogenic society is the sedentary life style of Americans. More than 60% of American adults are not regularly active, with 25% of the adult population being totally sedentary during their leisure time. Only approximately 15% of U.S. adults are involved regularly (i.e., three times a week for at least 20 minutes) in vigorous physical activity during leisure time. About 22% of adults engage regularly (i.e., five times a week for at least 30 minutes) in sustained physical activity of any intensity during their leisure time (U.S. Department of Health & Human Services, 2000; U.S. Department of Health & Human Services, 1996).

The statistics for children and adolescents are not any better. Nearly 50% of American youths 12-21 years of age do not engage in regular, vigorous activity, with physical activity declining dramatically during adolescence. Twenty-five percent of young people report that they are not involved in any vigorous physical activity during their leisure time (see U.S. Department of Health & Human Services, 1996).

Sedentary lifestyle and excess calories. Among all of the factors helping to create the immediate imbalance between the number of calories consumed with the number of calories expended, a sedentary lifestyle and the intake of excess calories in combination account for most of the variance in the imbalance, and, thus, are major factors in causing overweight and obesity. In a real and practical sense, diet and physical activity possess a synergistic impact on preventing excess calories and creating deficit calories, thereby, bringing about and sustaining a balance between consumed calories and expended calories.

References

Ayoob, K.T. (2010). Stop the blame and start the action: Preventing generation z from becoming xxl. Childhood Obesity, 6 (4), 164.

Ogden, C.L. & Carroll, M.D. (2010).  Prevalence of overweight, obesity, and extreme obesity among adults: United States, trends 1976–1980 through 2007–2008. NCHS Health E-Stat. Hyattsville, MD: National Center for Health Statistics. Retrieved September 25, 2010, from http://www.cdc.gov/nchs/data/hestat/obesity_adult_07_08/obesity_adult_07_08.pdf

U.S. Department of Health and Human Services (2000). Healthy people 2010: Understanding and improving health and objectives for improving health ( 2nd ed.). (Vol. 2, pp. 22/1 – 22/39).  Washington, DC: U.S. Government Printing Office.

U.S. Department of Health and Human Services (1996). Physical activity and health: A report of the surgeon general. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion. Atlanta, GA.


[1] See Garko (2011) for a definition and complete discussion on risk factors.

Suggested Citation: Garko, M.G. (2011, March). Overweight and obesity in America – Part VI: Modifiable Risk Factors. Health and Wellbeing Monthly. Retrieved (insert month, day, year), from www.letstalknutrition.com.