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Psychology

<OpenstaxParagraph>
	When someone weighs more than what is generally accepted as healthy for a given height, they are considered overweight or obese. According to the Centers for Disease Control and Prevention (CDC), an adult with a <OpenstaxTerm>body mass index</OpenstaxTerm> (BMI) between 25 and 29.9 is considered <OpenstaxTerm>overweight</OpenstaxTerm> (<a href="#Figure_10_02_BodyMass">Figure 10.10</a>). An adult with a <OpenstaxTerm>BMI</OpenstaxTerm> of 30 or higher is considered <OpenstaxTerm>obese</OpenstaxTerm> (Centers for Disease Control and Prevention [CDC], 2012). People who are so overweight that they are at risk for death are classified as severely obese. <OpenstaxTerm>Severe obesity</OpenstaxTerm> is defined as having a BMI over 40. Note that although BMI has been used as a healthy weight indicator by the World Health Organization (WHO), the CDC, and other groups, its value as an assessment tool has been questioned. The BMI is most useful for studying populations, which is the work of these organizations. It is less useful in assessing an individual since height and weight measurements fail to account for important factors like fitness level. An athlete, for example, may have a high BMI because the tool doesn’t distinguish between the body’s percentage of fat and muscle in a person’s weight. BMI scales have not accounted for differences in body composition related to race or ethnicity; as a result, BMI is less useful in determining health of all people. While many healthcare professionals and organizations still utilize BMI, the American Medical Association in 2023 recommended that it be removed as a standard measure of health.
</OpenstaxParagraph>
<OpenstaxFigure id="Figure_10_02_BodyMass" src="https://openstax.org/apps/archive/20240226.174525/resources/2ea5e9cd13a95fe5d967a640ca760178e3b16424" alt="A chart has an x-axis labeled “weight” (pounds/kilograms) and a y-axis labeled “height” (meters and feet/inches). Four areas are shaded different colors indicating the BMI for ranges of weight and height. The “underweight BMI &lt;18.5” area begins at approximately 90 pounds and 4’11” and extends to approximately 160 pounds and 6’6”. The “normal range BMI 18.5–25” area covers approximately 90–120 pounds at height 4’11” and extends to approximately 160–220 pounds at height 6’6”. The “overweight BMI 25–30” area covers approximately 120–140 pounds at height 4’11” and extends to approximately 220–265 pounds at height 6’6”. The “obese range BMI &gt;30” area covers approximately 140–350 pounds at height 4’11” and extends to approximately 265–350 pounds at height 6’6.”" mediaType="image/jpeg" width="731" height="597" />
<OpenstaxFigureText width="731">
	Figure 10.10 This chart shows how adult BMI is calculated. Individuals find their height on the y-axis and their weight on the x-axis to determine their BMI. While BMI is widely used and does provide some indications of health, it does not account for differences in people's body composition. The American Medical Association has recommended it be de-emphasized as a measure of health.
</OpenstaxFigureText>
<OpenstaxParagraph>
	Being extremely overweight or obese is a risk factor for several negative health consequences. These include, but are not limited to, an increased risk for cardiovascular disease, stroke, Type 2 diabetes, liver disease, sleep apnea, colon cancer, breast cancer, infertility, and arthritis. Given that it is estimated that in the United States around forty percent of the adult population is obese and that nearly three-quarters of adults and one in six children qualify as overweight (CDC, 2018), there is substantial interest in trying to understand how to combat this important public health concern. 
</OpenstaxParagraph>
<OpenstaxParagraph>
	What causes someone to be overweight or obese? You have already read that both genes and environment are important factors for determining body weight, and if more calories are consumed than expended, excess energy is stored as fat. However, socioeconomic status and the physical environment must also be considered as contributing factors (CDC, 2012). For example, an individual who lives in a neighborhood with high crime rates and few food options may never feel comfortable walking or biking to work or to the local market. This might limit the amount of physical activity in which they engage. Similarly, some people may not be able to afford healthy food options from their market, or these options may be unavailable (especially in urban areas or poorer neighborhoods); therefore, some people must rely primarily on available, inexpensive, high fat, and high calorie fast food as their primary source of nutrition.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Generally, people are encouraged to try to maintain and improve health through a combination of both diet and exercise. While some people are very successful with these approaches, many are not. In cases in which a person has had no success with repeated attempts to reduce weight or is at risk for death because of obesity, bariatric surgery may be recommended. <OpenstaxTerm>Bariatric surgery</OpenstaxTerm> is a type of surgery specifically aimed at weight reduction, and it involves modifying the gastrointestinal system to reduce the amount of food that can be eaten and/or limiting how much of the digested food can be absorbed (<a href="#Figure_10_02_Bariatric">Figure 10.11</a>) (Mayo Clinic, 2013). A recent meta-analysis suggests that bariatric surgery is more effective than non-surgical treatment for obesity in the two-years immediately following the procedure, but to date, no long-term studies yet exist (Gloy et al., 2013).
</OpenstaxParagraph>
<OpenstaxFigure id="Figure_10_02_Bariatric" src="https://openstax.org/apps/archive/20240226.174525/resources/2947d1ff4b16fec34e9d17204f4bd7aa7f56f6d8" alt="An illustration depicts a gastric band wrapped around the top portion of a stomach. A bulging area directly above the gastric band is labeled “Small stomach pouch.” The area directly below the stomach is labeled “Duodenum.” Down-facing arrows indicate the direction in which digested food travels from the esophagus at the top, down through the stomach, and into the duodenum." mediaType="image/jpeg" width="487" height="399" />
<OpenstaxFigureText width="487">
	Figure 10.11 Gastric banding surgery creates a small pouch of stomach, reducing the size of the stomach that can be used for digestion.
</OpenstaxFigureText>
<OpenstaxNote>
	<OpenstaxNoteTitle> Link to Learning </OpenstaxNoteTitle> 
	<OpenstaxParagraph>
		Watch this <a href="http://openstax.org/l/barsurgery">video that describes two different types of bariatric surgeries</a> to learn more.
	</OpenstaxParagraph>
</OpenstaxNote>
<OpenstaxNote>
	<OpenstaxNoteTitle> Dig Deeper </OpenstaxNoteTitle> <OpenstaxH3> Prader-Willi Syndrome </OpenstaxH3>
	<OpenstaxParagraph>
		<OpenstaxTerm>Prader-Willi Syndrome</OpenstaxTerm> (PWS) is a genetic disorder that results in persistent feelings of intense hunger and reduced rates of metabolism. Typically, affected children have to be supervised around the clock to ensure that they do not engage in excessive eating. Currently, PWS is the leading genetic cause of severe obesity in children, and it is associated with a number of cognitive deficits and emotional problems (<a href="#Figure_10_02_Obesity">Figure 10.12</a>).
	</OpenstaxParagraph><OpenstaxFigure id="Figure_10_02_Obesity" src="https://openstax.org/apps/archive/20240226.174525/resources/975c77eca0d335457fb94f9296739e6b28081806" alt="A painting shows Eugenia Martínez Vallejo." mediaType="image/jpeg" width="325" height="507" />
	<OpenstaxFigureText width="325">
		Figure 10.12 Eugenia Martínez Vallejo, depicted in this 1680 painting, may have had Prader-Willi syndrome. At just eight years old, she weighed approximately 120 pounds.
	</OpenstaxFigureText>
	<OpenstaxParagraph>
		While genetic testing can be used to make a diagnosis, there are a number of behavioral diagnostic criteria associated with PWS. From birth to 2 years of age, lack of muscle tone and poor sucking behavior may serve as early signs of PWS. Developmental delays are seen between the ages of 6 and 12, and excessive eating and cognitive deficits associated with PWS usually onset a little later.
	</OpenstaxParagraph>
	<OpenstaxParagraph>
		While the exact mechanisms of PWS are not fully understood, there is evidence that affected individuals have hypothalamic abnormalities. This is not surprising, given the hypothalamus’s role in regulating hunger and eating. However, as you will learn in the next section of this chapter, the hypothalamus is also involved in the regulation of sexual behavior. Consequently, many individuals suffering from PWS fail to reach sexual maturity during adolescence.
	</OpenstaxParagraph>
	<OpenstaxParagraph>
		There is no current treatment or cure for PWS. However, if weight can be controlled in these individuals, then their life expectancies are significantly increased (historically, sufferers of PWS often died in adolescence or early adulthood). Advances in the use of various psychoactive medications and growth hormones continue to enhance the quality of life for individuals with PWS (Cassidy &amp; Driscoll, 2009; Prader-Willi Syndrome Association, 2012).
	</OpenstaxParagraph>
</OpenstaxNote>

10.2.3 Obesity

1 Introduction to Psychology

1.1 What Is Psychology?

1.1.1 Why Study Psychology?

1.2 History of Psychology

1.2.1 Wundt and Structuralism

1.2.2 Functionalism

1.2.3 Freud and Psychoanalytic Theory

1.2.4 Wertheimer, Koffka, Köhler, and Gestalt Psychology

1.2.5 Pavlov, Watson, Skinner, and Behaviorism

1.2.6 Maslow, Rogers, and Humanism

1.2.7 The Cognitive Revolution

1.2.8 Multicultural And Cross-Cultural Psychology

1.2.9 Women in Psychology

1.3 Contemporary Psychology

1.3.1 Biopsychology and Evolutionary Psychology

1.3.2 Sensation and Perception

1.3.3 Cognitive Psychology

1.3.4 Developmental Psychology

1.3.5 Personality Psychology

1.3.6 Social Psychology

1.3.7 Industrial-Organizational Psychology

1.3.8 Health Psychology

1.3.9 Sport and Exercise Psychology

1.3.10 Clinical Psychology

1.3.11 Forensic Psychology

1.4 Careers in Psychology

1.4.1 Other Careers in Academic Settings

1.4.2 Career Options Outside of Academic Settings

2 Psychological Research

2.1 Why Is Research Important?

2.1.1 Use of Research Information

2.1.2 NOTABLE RESEARCHERS

2.1.3 The Process of Scientific Research

2.2 Approaches to Research

2.2.1 Clinical or Case Studies

2.2.2 Naturalistic Observation

2.2.3 Surveys

2.2.4 Archival Research

2.2.5 Longitudinal and Cross-Sectional Research

2.3 Analyzing Findings

2.3.1 Correlational Research

2.3.2 Causality: Conducting Experiments and Using the Data

2.3.3 Reliability and Validity

2.4 Ethics

2.4.1 Research Involving Human Participants

2.4.2 Research Involving Animal Subjects

3 Biopsychology

3.1 Human Genetics

3.1.1 Genetic Variation

3.1.2 Gene-Environment Interactions

3.2 Cells of the Nervous System

3.2.1 Neuron Structure

3.2.2 Neuronal Communication

3.2.3 Neurotransmitters and Drugs

3.3 Parts of the Nervous System

3.3.1 Peripheral Nervous System

3.4 The Brain and Spinal Cord

3.4.1 The Spinal Cord

3.4.2 The Two Hemispheres

3.4.3 Forebrain Structures

3.4.4 Midbrain and Hindbrain Structures

3.4.5 Brain Imaging

3.5 The Endocrine System

3.5.1 Major Glands

4 States of Consciousness

4.1 What Is Consciousness?

4.1.1 Biological Rhythms

4.1.2 Problems With Circadian Rhythms

4.2 Sleep and Why We Sleep

4.2.1 What is Sleep?

4.2.2 Why Do We Sleep?

4.3 Stages of Sleep

4.3.1 NREM Stages of Sleep

4.3.2 REM Sleep

4.4 Sleep Problems and Disorders

4.4.1 Insomnia

4.4.2 Parasomnias

4.4.3 Sleep Apnea

4.4.4 Narcolepsy

4.5 Substance Use and Abuse

4.5.1 Substance Use Disorders

4.5.2 Drug Categories

4.6 Other States of Consciousness

4.6.1 Hypnosis

4.6.2 Meditation

5 Sensation and Perception

5.1 Sensation versus Perception

5.1.1 Sensation

5.1.2 Perception

5.2 Waves and Wavelengths

5.2.1 Amplitude and Wavelength

5.2.2 Light Waves

5.2.3 Sound Waves

5.3 Vision

5.3.1 Anatomy of the Visual System

5.3.2 Color and Depth Perception

5.4 Hearing

5.4.1 Anatomy of the Auditory System

5.4.2 Pitch Perception

Question	Answer
type of surgery that modifies the gastrointestinal system to reduce the amount of food that can be eaten and/or limiting how much of the digested food can be absorbed	bariatric surgery
adult with a BMI of 30 or higher	obese
adult with a BMI between 25 and 29.9	overweight
adult with a BMI over 40	severe obesity