Module 10: The Food Environment: Growth and Obesity

Overview: The Food Environment

There is a growing recognition that the food environment can impact individual and community health has led to an interest in studying the effect of exposure to different ‘types of food environments as well as explor­ing ways of bringing about changes that would support positive health outcomes. A number of conceptual models focusing on food environments have been proposed in the. One model for understanding food and nutrition environments (Figure 1) incorporates constructs from the fields of public health, health psychology, consumer psychology, and urban planning. The model identified four types of nutrition environments (community, consumer, organizational, and information) that need to be understood, and those environments can be affected by policies of governments and other organizations (Glanz et al. 2005).

Figure 1. Model of Community Nutrition Environments (Glanz, Sallis, Saelens & Frank 2005).

Another model, the biocultural approach recognizes that culture, social circumstances and environmental factors intersect to shape food related behaviors, nutritional status and coping strategies. It also posits how people perceive their environment is important because perceptions structure responses that can affect physical and emotional well being and health. That is, an individual’s behavior, such as a choice to eat a specific food, or label a food healthy is influenced both by the environment in which they live and their personal characteristics. This influence is ongoing and dynamic, with all three elements (the characteristics of the individual, the individual’s behavior, and the individual’s social and physical environment) mutually interacting.

Consequently, the consumer environment identified by Glanz et al. (2005) is of particular interest when trying to identify specific environmental fators that can shape food acquisiton behavior. Consumer food environments are what consumers encounter within and around retail food outlets (stores, restaurants, and within-organization food sources) and include the availability and price of healthful food choices. A growing body of research has examined the association between food availability/ access (food store type, restaurant type, distance, food prices) and dietary and health outcomes. Findings, related to food access and availability in the consumer environment, include:

1. Larger food -store size is associated with better access to fresh fruits and vegetables and other nutrient dense food.

2. The availability of supermarkets is associated with healthier diets, lower rates of obesity, and a longer life span.

3. Individuals who live in neighborhoods with access to food stores and restaurants that carry healthier choices are more likely to consume better-quality diets, including greater consumption of fruits and

4. Availability and access to healthy food outlets are associated with improved diet-related health outcomes, such as lower rates of overweight, obesity and diabetes.

See Black Board for Module 10 & 11 Activity
Overview: Growth

Evaluating the quality of an individual’s growth and thus nutritional status can be done in a number of ways. This module focuses on a number of concepts related to collecting, developing and using standards for growth. In particular we will explore the processes by which individuals grow and mature from infancy to adolescence. We will focus on childhood from the age 1 – 5 since this is the period that is considered to be most reflective of nutritional and health status. We will utilize anthropometric data from an Afro-Ecuadorian population in order to evaluate nutritional status.

Objectives

1. Introduce the basic concepts related to growth

2. Review human growth and development from infancy to through adolescence

3. Review how nutrition impact growth and development

***************************************************

Notes

Nutrition and Growth

  • Nutritional status: evaluation of the nutritional health of an individual or population
    • Anthropometry
      • Height/length
      • Weight
      • Skinfolds:
      • Arm circumference
    • Body composition
      • Skinfold thickness
      • Densitometry
      • Ultrasound
    • Biochemical evaluation: anemia, trace metals
      • Blood
      • Urine
      • Hair
      • Nails
      • Saliva
    • Clinical exam:
      • Skin
      • Nails
      • Hair
      • Eyes
      • Mouth
      • Thyroid

APPROACHES TO THE STUDY OF GROWTH

Perspectives: Within Anth. Main areas of Interest:

  1. Growth assessment methodology
  2. Antecedents of morbid conditions
  3. Environment vs. genetics

Overview of Concepts:

Definition:

  • Growth: (increase in size of body as a whole or an increase in any of its parts associated with an increase in cell number and/or size.
  • Development: acquisition of function associated with cell differentiation and maturation of individual organ systems.

Growth and development affected by:

  • genetics, hormonal, environmental and behavioral factors
  • Social & Demographic factors:
  • family income; family size; birth order; parental education; (all indirect)
  • As indicated before physical growth is used as an indicator of nutritional status: Ht, Wt, Wt/HT & growth pattern – Ht/age; Wt/age

We usually think of growth and development proceeding in an orderly and predictable sequence but there is individual variation.

Critical periods of growth:

  • hyperplasia – inc. in cell number
  • hypertrophy – increase in cell size
  • hypertrophy and hyperplasia – both inc in cell size and number

The period of hyperplasia

  • is a time the organism/organ is most vulnerable to compromised nutrition and can be considered critical to an individuals acquisition of normal complement of cells.

Growth Assessment Methods:

Growth Measurements:

  • height, weight, volume and thickness of tissues, head circumference, Quetelet’s Index: wt/ht2 (weight divided by square of height); wt/ht (W/H); ht/age;

Growth Standards:

A number of standards have been developed to make it possible to:

  1. compare the measurements of any one child to other children of the same sex, age and “ethnic group”/population (race).
  2. compare a child’s present measurements with their former rate of growth and pattern of progress.
  • The normal Distribution
  • The standard deviation
  • The percentile chart:
    • percentile: generally refers to any percentile rank
    • percentile level: refers to specific percentile values selected to show the extent to which an individuals measurements deviate from the median (50th percentile)

Growth Curves:

Distance/ cummulative – how much, how much growth achieved

  1. Obtained by plotting a series of consecutive measurements
  2. It shows the cummulative or total amount of growth that has occurred over a period of time

Velocity – how fast or rate of growth

  1. Obtained by plotting consecutive growth increments or changes over a series of time intervals.
  2. It shows the rate of growth, or the amount of growth per unit of time

Growth Pattern Terms/Concepts:

  • acceleration
  • deceleration
  • maximum growth
  • peak growth velocity
  • decimal age

CHILDHOOD

Periods of Childhood:

  • Prenatal
    • embryonic: conception – 8 wks
    • middle fetal:9-24 wks
    • late fetal: 25 wk-birth
  • Infancy
    • Neonatal: birth – 1 month
      • Postnatal
      • Perinatal
    • Infancy: 1 month – 1 yr
    • Late Infancy second year
  • Childhood:
    • females: 2 – 10
    • males: 2 – 12
  • Adolescence
    • Prepubescence:
      • females: 10 – 12
      • males: 12 – 14
    • Pubescence:
      • females: 12 -14
      • males: 14 – 16
    • Postpubescence:
      • females: 14 – 18
      • males: 16 – 20

PRENATAL/INFANCY/CHILDHOOD

  • Factors affecting prenatal development: special anth interests:
    • nutrition; hypoxia; inter-generational effect
  • Birth weight: Factors
    • pregnancy weight
    • weight gain during pregnancy
      • low birth weight:
        • after birth genetic influence – “target seeking”
        • a period of “catch-up or “lag down” may occur
        • many children who are genetically determined to be longer may shift channels at 3 to 6 months.
        • many children at or below the 10 percentile who are genetically determined to be of average height may not achieve a channel until a year of age.
        • Immediately after birth there is a weight loss, but birth weight is usually regained by 10th day. Thereafter weight gain in infancy proceeds at a rapid but decelerating rate.
  • General trends:
    • double birth weight after 4 month
    • tripled birth weight by 12 months
  • Gender differences:
    • males double birth weight earlier than females

After the first year growth proceeds at a slower and constant rate: 2.3 kg/yr until 9 or 10. Another, but less dramatic growth period occurs in adolescence.

Body Composition

Changes occur not only in height and weight but also in the components of the tissues. Increases in height and weight and skeletal maturation are accompanied by changes in body composition – in adiposity, lean body mass and hydration.

Fat:

Fat is found in adipose tissue, in sites in the bone marrow, in phospholipids in the brain and nervous system, and as part of cells.

Fat is the component of the body in which the greatest differences between children, age groups, and sexes is seen

The fat content of the body increases slowly during early fetal development , then increases rapidly in the last trimester. It accumulates rapidly during infancy until about 9 months of age. Between 2 an 6 months the increase of adipose tissue is more than twice that of volume of muscle.

Sex- related differences appear in infancy, the female depositing a greater percentage of weight as fat than the male.

Adipose tissue and periods of hyperplasia – discussion/ controversies etc.

  • The Period of Toddlerhood:
    • (much of this from Cassidy in Green & Johnston)
    • 13 – 48 months / 2-4 years
    • difficult psychologically and physiologically:
  • High mortality and morbidity rates (year 2 most difficult)
    • Industrialized : toddler mortality – 15% of inf rate
    • Non-industrialized : 50% of inf

Rates for malnutrition and infection peak:

  • PEM
    • Kwashiorkor
    • Marasums
    • Mild to moderate malnutrition

Customs that potentiate malnutrition:

many are discovered when investigating rules and practices governing toddler diet

Expressions of benign neglect during toddler years

benign neglect – actions permitted or encouraged by customs and beliefs which potentiate physical dysfunction although their goal is to achieve positively valued social effect.

  1. Exacerbation of psychological stress during weaning
  2. Food restriction
  3. Food competition:

Discriminatory Feeding patterns

  • food distribution/ consumption:
  • arenas:
    • order of eating – who eats first: ramification (amt avail; potion to each)
      • evidence rates of malnutrition – adult male, children, then women
  • gender associated types of food (food observ)
  • taboo and prohibitions

Consequences:

  • Biological Issues
    • Discrimination in the care of girls can negate their biological advantage in many countries girls are in poorer health (India, China, Bangladesh)
  • Cultural Issues:
    • differential breast feeding
    • gastro-political socialization:

ADOLESCENCE

  • The adolescent period is a unique stage in the process of growth and development:
    • rapid change
    • wide variability in norms
    • inc. independent behavior
  • Adolescence lasts nearly a decade and has no specific beginning or end
    • Changes occur on a variety of levels:
    • physiological
    • psychological
    • social

Physical Growth and Puberty

  • velocity of growth during this time is second only to the period of infancy
    • Adolescent growth –
    • inc in cell number and size
    • inc. in reproductive maturity
  • To support growth:
    • high demand for calories
    • high demand for nutrients
  • The end of adolescence is usually signaled by:
    • slowing of growth
    • completion of sexual maturation
    • closure of epiphyses of long bones
  • Prepubescent Growth Spurt:
    • begins about 2 yrs earlier for females
    • at this time females:
    • temporarily taller
    • have larger limb muscle mass
  • As pubertal growth proceeds males:
    • males develop more muscle – and skeleton enlarges esp. shoulder region
    • female – smaller inc in muscle, pelvis rounds out and enlarges
    • inc in fat deposition however fat will diminish gradually in 1 – 2 years
  • Most rapid phase of adolescent growth – growth spurt
    • highest point – called the peak

Growth velocity decelerates from birth until pubertal growth spurt at which time the velocity of a 14 yr old boy is about the same as a 2 year old.

Obesity Notes

Theory is both a tool for methodology and a tool for defining obesity

· A biocultural approach to obesity is necessary

· Additionally, micro factors, or “additional cognitive and environmental factors” * need to be considered along with the macro (A full picture of genes, society and the individual).

*Ulijaszek and Lofink. Obesity in Biocultural Perspective. Annu. Rev. Anthropology. 2006. 35: 347

· Theory as frame and definition

More than providing frames, informing methodology, or casting light and shadow on topics of study relative to obesity, theory is as much a part of its constitution as metabolism, tissues, food consumption habits and one’s physical and cultural environments: it helps to establish defining contours of obesity. For example, it gives us “obesogenic environments” *, defining obesity not just as genetic but cultural, in its approach, and therefore defines obesity itself in this dual-way.

*Ulijaszek and Lofink. Obesity in Biocultural Perspective. Annu. Rev. Anthropology. 2006. 35: 338; 350.

Gender Issues

· Feminist theory in obesity research is interesting for a number of bio-social factors:

o Sexual dimorphism: to females with more peripheral fat storage (reproduction and lactation costs).

Further, peripheral fat storage is not associated with harmful health effects. Yet, females experience the largest social pressures to essential deny this genetic truth

Gender and class

Additionally, females most susceptible to obesity are adult females in poverty; though in childhood and adolescents, affluent females are more so.

For females of poverty who become obese, many are also identified in minority populations. (A class inversion with poverty)

Obesity for females, then, is a doubly, and perhaps triply, stigmatized.

Age Theory/ Ecologies of Childhood

Specifically with regard to Childhood obesity, there are some interesting intergenerational and age factors to consider:

Parents contend with intergenerational norms and education; as well as combat their consumption patterns.

They also must prioritize other such things as ‘family peace’ at the dinner table, which often translates into special food for the children

Brewis and Gartin. Biocultural Construction of Obesogenic Ecologies of Childhood: Parent-Feeding Versus Child-Eating Strategies. American Journal of Human Biology 18: 203-213. 2006.

Age Theory/ Ecologies of Childhood

Furthermore, there needs to consideration of Child agency:

for example, the “‘finicky’” child * may provide insight on the negotiation between internal indicators and learned social cues to eat.

Brewis and Gartin. Biocultural Construction of Obesogenic Ecologies of Childhood: Parent-Feeding Versus Child-Eating Strategies. American Journal of Human Biology 18: 203-213. 2006.

Obesogenic Environment

The term obesogenic environment was coined by Swinburn et al. (1999)

argued that the physical, economic, social, and cultural environments of the majority of industrialized nations encourage positive energy balance in their populations.

A dominant explanatory framework for the emergence of obesogenic environments is that of nutrition transition (Popkin 2004),

which relates globalization, urbanization, and westernization to changing foodenvironments across the populations of the world (Drewnowski & Popkin 1997, Griffiths

While obesity has existed in various forms for centuries, it has only been an “epidemic” * for last half century.

Today, we live in “obesogenic environments” – or contexts “against an evolutionary heritage” *

These are “physical, economic, social, and cultural environments of the majority of industrialized nations [which] encourage positive energy balance in their populations” *

Winson, A. Bringing political economy into the debate on the obesity epidemic. Agriculture and Human values 21: 299. 2004

Embedded within these theories, or alongside them, are additional theoretical frameworks such as:

Colonialism

Neocolonialism

Spatial colonization

Feminism

Class theory

CDC Charts (See CDC page)
Assignment (See assignments page)