Chapter 4: Body Composition and Obesity

How much of your body weight comes from your bones, muscles, organs, or body fat?

Have you ever tried a diet to lose weight?

Are there differences in health outcomes based on where you store body fat?

The information in this chapter comes primarily from the following websites:

Chapter 4 Learning Outcomes

By the end of this chapter you will be able to:

  • Recognize the role fat plays in health and disease
  • Explain the prevalence of obesity
  • Compare and contrast the use of BMI and Body Composition measurements
  • Describe negative health consequences of obesity and overweight
  • Explain the difference between type 1 and type 2 diabetes
  • Identify actions that could be implemented to reduce obesity
  • Recognize the signs of body dysmorphic disorders and eating disorders

Intro to Weight Management

It is highly likely that you have seen weight loss ads in the newspaper, magazines, or in your social media feed.  With about 50% of the U.S. population saying they tried to lose weight in the last 12 months[1], it is not surprising that the weight loss industry is estimated to be a $3 billion dollar industry.

Although this chapter will address those who are underweight, the predominance of information will relate to persons who are overweight or obese.  Overweight and obesity are linked to more deaths worldwide than underweight; most of the world’s population live in countries where overweight and obesity kills more people than underweight.  In the U.S., an estimated 1.5% of adults aged 20 and over are underweight[2], compared to about 42% of adults who are considered obese.  The goal is to strive for a healthy weight since persons who are underweight or overweight have negative health implications.

This chapter focuses on  body weight and body composition.  Both body weight and body composition are important measurements to understand your health.  Body weight is typically measured in pounds or kilograms and is simply your body’s total mass.  Body composition is what your weight is made of  (muscle, bone, water, and fat) and is typically measured as a percentage.  For example, a person might have a body weight of 200 lbs and a percentage body fat of 25%, in this example, 50lbs of their body weight comes from fat.   Although body weight is the measurement most commonly used to assess the health of our body size, body composition is a more accurate look at our body size by understanding what the body is made up of.  It is quick and easy to step on a scale and measure your body weight, but measuring body composition is much more challenging, thus body weight is the standard used to address overweight and obesity.

Fat is not bad, we need fat for healthy cellular function, energy, cushioning for vital organs, insulation, long term energy storage, and absorption of fat-soluble vitamins.   The minimum about of body fat needed by males is about 3%  and females is about 12%.  It is generally accepted that an overall range of 10-22 percent for men and 20-32 percent for women is considered satisfactory for good health.  This necessary body fat for health is considered essential body fat.  When the body stores additional body fat above the essential amount it is called non-essential body fat.  A woman’s essential fat range is naturally greater than a man’s because of fat deposits in breasts, uterus and sex-specific sites.

The Calorie Balance Equation and Metabolism

In chapter 3 (Nutrition) you were introduced to the energy (Calorie) balance equation, which simply means to compare energy in versus energy out, or how many Calories we are eating each day compared to the amount of Calories we expend.  If a persons consumes an excess of 3,500 Calories that is the equivalent of gaining one pound of weight.  That means if you reduce your daily calorie intake by 500 calories or burn 500 more calories each day than you consume, you may be able to lose a pound a week.  Caloric expenditure is most often associated with exercise, however most of our daily caloric expenditure is to maintain bodily functions, like breathing, circulating our blood, and digesting food.

The term used to describe the chemical processes in the body that convert Calories into energy is Metabolism.  Your body needs a minimum number of Calories to sustain these functions.  Basal Metabolic Rate (BMR) and Resting Metabolic Rate (RMR) are measurements used to estimate how many calories your body burns when you’re not exercising.  These two measurements are often used interchangeably, however they do have a slight difference.  A BMR measurement is slightly more accurate because it is measured when you are doing nothing, just upon waking up, while laying down in a dark room after sleeping for for at least eight hours and fasting for 12 hours.  RMR is taking without the strict conditions of the BMR; BMR is usually slightly lower than your RMR.  Both Basal metabolic rate (BMR) and resting metabolic rate (RMR) measure the amount of energy (Calories) that your body needs to stay alive and function properly.  It is helpful to understand your BMR/RMR since it accounts for about 60-80% of total energy expenditure each day.  Your BMR/RMR is effected by your weight, height, age, gender, and genetics.  A key component of your weight that impacts BMR/RMR is the amount of muscle you have; muscle mass increases BMR/RMR.

Defining Overweight and Obese

The measurement used across the world to identify if a person is overweight or obese is called the Body Mass Index (BMI), which is based on a persons weight versus their height.    BMI is used because it is an inexpensive and easy screening method to identify weight categories (underweight, healthy weight, overweight, and obesity).  It is important to recognize that BMI does not assess body composition or body fatness, it is simply a measurement of body size and is used as a screening tool.  Although it may not be accurate for some of the population, for example athletes with high muscle mass, it has been shown to be correlated to other more accurate measures of body fatness and to various weight related diseases.

BMI is a person’s weight in kilograms divided by the square of height in meters:

BMI= weight (kg) / [height (m)]2

Table 4.1:  BMI Indicators
BMI Weight Status
Below 18.5 Underweight
18.5 – 24.9 Healthy Weight
25.0 – 29.9 Overweight
30.0 and Above Obesity
Table 4.2:  BMI Example for person who is 5’9″
Height Weight Range BMI Weight Status
5’9″ 124 lbs or less Below 18.5 Underweight
5’9″ 125 lbs to 168 lbs 18.5 to 24.9 Healthy Weight
5’9″ 169 lbs to 202 lbs 25.0 to 29.9 Overweight
5’9″ 203 lbs or more 30 or higher Obesity
As noted previously, BMI is the most commonly used tool to assess health weight, but for many people it is not an accurate measurement because it does not assess your body composition.  For example, two people can have the exact same height and weight, thus the same BMI, but one could be a professional athlete who is very active with low body fat and the other could be sedentary with high body fat.  Using the example in Table 4.2, a person who is 5’9″ and 203 pounds is considered obese using the BMI, it does not matter whether that person is a 203 pound professional weight lifter or a sedentary person with high body fat.

Activity: What is your Body Mass Index?


There are many BMI calculators available online to quickly calculate your BMI.

Take a minute and go to the CDC’s Adult BMI Calculator and enter your height and weight.

Evaluate your BMI results:

  • Are you considered underweight, healthy weight, overweight, and obese?
  • Does the BMI result seem accurate for you and your body composition?

Obesity Epidemic

Figure 4.1: Changes in obesity rates by state from 1985-2006

Obesity in The U.S. 

The number of people with obesity has been increasing for decades. Results from the 2017–2018 National Health and Nutrition Examination Survey (NHANES)[3] provide estimated percentages across time showing the growing trend.  Data from the years 1988-1994 through 2017–2018, show obesity prevalence of adults in the U.S. increased from 22.9% to 42.4%.  During the same time, the prevalence of severe obesity in adults increased from  2.8% to 9.2%.  The data shows that children in the U.S. are also impacted by obesity with the percentage of obese children ages 2 through 19 in the United States increasing from 10% in 1988-1994 to 19.3% in 2017-2018 (refer to Tables 4.3 and 4.4).

Table 4.3: Prevalence of Overweight and Obesity Among Adults 20 and over from 1988 through 2018
Selected data from the 2017–2018 National Health and Nutrition Examination Survey (NHANES)
Years Percentage Overweight Percentage Obese Percentage Severely Obese
1988-1994 33.1 22.9 2.8
1999-2000 34 30.5 4.7
2005-2006 32.6 34.3 5.9
2011-2012 33.6 34.9 6.4
2017-2018 30.7 42.4 9.2
Table 4.4: Prevalence of Overweight and Obesity AmongChildren 2-19 from 1988 through 2018
Selected data from the 2017–2018 National Health and Nutrition Examination Survey (NHANES)
Years Percentage Overweight Percentage Obese Percentage Severely Obese
1988-1994 13 10 2.6
1999-2000 14.2 13.9 3.6
2005-2006 14.6 15.4 4.7
2011-2012 14.9 16.9 5.6
2017-2018 16.1 19.3 6.1

Obesity in The World

The U.S. is not the only country seeing a rise in obesity.  Since 1975, obesity across the world has nearly tripled.  Data from 2016 show that more than 1.9 billion (39%) adults around the world were overweight with 650 million (13%) obese.  Most of the world’s population live in countries where overweight and obesity kills more people than underweight.

The number of obese children and adolescents (aged five to 19 years) worldwide has risen tenfold in the past four decades. Obesity rates in the world’s children and adolescents increased from less than 1% (equivalent to five million girls and six million boys) in 1975 to nearly 6% in girls (50 million) and nearly 8% in boys (74 million) in 2016.  In 2016, there were 50 million girls and 74 million boys with obesity in the world, while the global number of moderately or severely underweight girls and boys was 75 million and 117 million respectively. If current trends continue, more children and adolescents will be obese than moderately or severely underweight by 2022[4].

Negative Health Implications of Obesity

People who have obesity, compared to those with a normal or healthy weight, are at increased risk for many serious diseases and health conditions, including the following:

  • All-causes of death (mortality)
  • High blood pressure (Hypertension)
  • High LDL cholesterol, low HDL cholesterol, or high levels of triglycerides (Dyslipidemia)
  • Type 2 diabetes
  • Coronary heart disease
  • Stroke
  • Gallbladder disease
  • Osteoarthritis (a breakdown of cartilage and bone within a joint)
  • Sleep apnea and breathing problems
  • Many types of cancer
  • Low quality of life
  • Mental illness such as clinical depression, anxiety, and other mental disorders4
  • Body pain and difficulty with physical functioning

Understanding Diabetes

As you learned at the beginning of this chapter, the body breaks down the food we eat to turn it into energy, this process is called metabolism.  The disease that affects how your body turns food into energy is called Diabetes. There are three main types of diabetes: type 1, type 2, and gestational diabetes (diabetes while pregnant). More than 122 million Americans are living with diabetes (37.3 million, 11.3% of the US population) or prediabetes (96 million, 38.0% of the adult US population).

When discussing diabetes you will often hear people talk about Insulin.  Most of the food you eat is broken down into sugar (also called glucose) and released into your bloodstream. When your blood sugar goes up, it signals your pancreas to release insulin. Insulin acts like a key to let the blood sugar into your body’s cells for use as energy.   Without insulin, blood sugar can’t get into cells causing the blood sugar to build up in the bloodstream. High amounts of blood sugar are damaging to the body and causes many of the symptoms and complications of diabetes.

If you have type 1 diabetes, your pancreas doesn’t make insulin or makes very little insulin.  Approximately 5-10% of the people who have diabetes have type 1.  Type 1 Diabetes is usually diagnosed in children, teens, and young adults.  Type 1 diabetes is thought to be caused by an autoimmune reaction (the body attacks itself by mistake) that stops your body from making insulin.

If you have type 2 diabetes, your cells don’t respond normally to insulin. About 90-95% of people with diabetes have type 2.  It develops over many years and is usually diagnosed in adults (but more and more in children, teens, and young adults). Type 2 diabetes can be prevented or delayed with healthy lifestyle changes, such as losing weight, eating healthy food, and being active.

You’re at risk for developing type 2 diabetes if you:

  • Have prediabetes
  • Are overweight
  • Are 45 years or older
  • Have a parent, brother, or sister with type 2 diabetes
  • Are physically active less than 3 times a week
  • Have ever had gestational diabetes (diabetes during pregnancy) or given birth to a baby who weighed more than 9 pounds
  • Are African American, Hispanic/Latino American, American Indian, or Alaska Native (some Pacific Islanders and Asian Americans are also at higher risk)

Assessing Body Composition

As noted previously, BMI is the measurement used as a screening tool to quickly and inexpensively identify whether a person is at a healthy weight, is underweight, overweight, or obese.  BMI is not a measure of body composition, it will not tell you whether you are overfat, it will only tell you whether you are overweight.  Understanding what the body is made up of (muscle, bone, water, and fat) is a better predictor of health, however the tools used to measure body composition can be expensive, intrusive, not widely available, or difficult to standardize across observers or machines.  Due to the challenges with measuring body composition, BMI is considered the best method.

When evaluating body composition, there are two general types of evaluations, body fat distribution and body fat percentage.

Body Fat Distribution

Fat is stored as subcutaneous fat, which is fat stored just under the skin, and visceral fat, which is fat stored deeper in the body around the organs. We are all different and one difference we have is where we store body fat.  Body fat distribution, meaning where a person stores their fat, has health implications.  Visceral fat tends to be store around the abdomen and research indicates high amounts of visceral fat lead to negative health implications including all-cause mortality[5].

One method for evaluating body composition is to look in the mirror at the outline of the body.  People are often described as being either apple shaped, carrying body fat around the abdomen,  or pear shaped, carry body fat around the hips.  People who are apple-shaped, thus carrying excess visceral fat around the abdomen, are at higher risk of developing health issues.

Besides looking in the mirror, body fat distribution can be measured by calculating a person waist circumference, waist-to-hip ratio, and waist-to-height ratio.

  • Waist Circumference
    • Stand and place a tape measure around your middle, just above your hipbones.  Measure your waist in inches just after you breathe out
      • Your waistline may be telling you that you have a higher risk of developing obesity-related conditions if you are
        • A man whose waist circumference is more than 40 inches
        • A non-pregnant woman whose waist circumference is more than 35 inches
  • Waist-to-Hip Ratio
    • You can calculate your waist-to-hip ratio by taking your waist circumference and dividing it by your hip circumference. The World Health Organization categorizes high risk as a ratio above 0.85 for women and more than 0.9 for men.
  • Waist-to-Height Ratio  (WHtR)
    • You can calculate your waist-to-height ratio by dividing your waist circumference by your height.   A waist-to-height ratio of more than 0.5 may put you at higher risk for heart disease and diabetes.  Waist-to-height ratio has been shown to be a good predictor of both BF% and Visceral Fat mass in men and women[6].

Body Fat Percentage

Body fat percentage is attempting to measure the percentage of your body that is fat-free mass versus fat mass.  There are several measurement tools to estimate body fat percentage, each have pros and cons mostly related to difficulty, cost, and availability.

  • Bioelectrical Impedance Analysis (BIA)
    • Bioelectrical Impedance Analysis is likely the measuring method you are most familiar with.  Have you ever used a scale that told you your body fat percentage?  If so, you have used BIA.  BIA devices emit a low-level electrical current through the body and measure the amount of resistance the current encounters. Based on the level of impedance, a pre-programed equation is used to estimate body fat percentage. Fat-tissue contains little water, making it a poor conductor of electricity; whereas, lean tissue contains mostly water and electrolytes, making it an excellent conductor. The most accurate BIA devices use electrodes on the feet and hands to administer the point-to-point electrical current.  Because BIA devices primarily measure hydration, circumstances that may influence hydration status at the time of measurement must be taken into account. Recent exercise, bladder content, hydration habits, and meal timing can cause wide measurement variations and influence accuracy. However, this method is generally inexpensive, often portable, and requires limited training to use, making it a very practical option.
  • Skinfold Calipers
    • Skinfold analysis is a widely used method of assessing body composition because of its simplicity, portability, and affordability.  Some call the skinfold test the “pinch test” because the skin and underlying subcutaneous fat is pinched with calipers to measure the thickness.  The assumption of skinfold measurement is that the amount of subcutaneous fat is proportionate to overall body fat.   These numbers are plugged into an equation to generate an estimate of body fat percentage. The skinfold test is fairly accurate when administered properly.
  • Hydrostatic Weighing (underwater weighing)
    • Hydrostatic weighing is a difficult process, but has long been considered the “gold standard” for assessing body composition.  A person is weighed when dry and then enters a water tank and is weighed while underwater.   Since fat is less dense than muscle tissue, a person with more body fat will weigh less in the water than a similar person with more lean mass. Using the measurements, the density can be determined and converted into body fat percentage. With a small margin of error (around 1-2%) this method is very accurate. Unfortunately, the expense and practicality of building and maintaining a water tank limits access for most.  This method is also challenging for people who are afraid of water, don’t feel comfortable in bathing suits, or would be fearful of exhaling all air and sitting underwater without moving for a short time.
  • Air Displacement (Plethysmography)
    • Plethysmogography works similarly to hydrostatic weighing however measures the displacement of air instead of water. The Bod Pod is most commonly referenced machine. During the test, a person sits in a chamber that varies the air pressure allowing for body volume to be assessed.  Air displacement provides a viable alternative for those with a fear of water. Like many other methods, the expense, availability, and training of personnel Air Displacement requires limit accessibility. Additionally, its accuracy is slightly less than underwater weighing.
  • Dual X-ray Absorptiometry (DXA)
    • Replacing underwater weighing as the new “gold standard,” DXA provides a quick and pain free method for measuring body fat by scanning the body.  The patient lays down and is scanned by the DXA machine which takes about 6 minutes. Major disadvantages to this method are its high cost and the need for a welltrained professional to operate the equipment and analyze the results.

Factors Contributing to Obesity

Although weight is often simplified to the Calorie Balance equation, it is much more complicated than just the amount of energy consumed versus expended.  There are many factors that contribute to overweight and obesity.  Some factors can be changed, such as unhealthy lifestyle habits and environments, and others cannot be changed, such as age, family history and genetics, race and ethnicity, and sex.

Unhealthy Lifestyle Factors

We make healthy and unhealthy choices everyday and many of those choices impact our likelihood of becoming overweight or obese.  These include: Lack of physical activity, unhealthy eating patterns, not enough sleep, and high amounts of stress.

  • Lack of physical activity
    • Lack of physical activity increases your risk of obesity and type 2 diabetes.  Strong scientific evidence shows that physical activity helps people maintain a stable weight over time and can reduce the risk of excessive weight gain and the incidence of obesity.
    • Healthy lifestyle changes, such as being physically active and reducing screen time, can help you aim for a healthy weight.
  • Unhealthy Eating Behaviors/Unhealthy Diet Patterns
    • Some unhealthy eating behaviors can increase your risk for overweight and obesity.
      • Eating more calories than you use.
      • Eating too much saturated and trans fats
      • Eating foods high in added sugars
      • Not eating enough Fiber
  • Not enough sleep
    • Many studies have seen a high BMI in people who do not get enough sleep. Some studies have seen a relationship between sleep and the way our bodies use nutrients for energy and how lack of sleep can affect hormones that control hunger urges.
  • High amounts of stress
    • Acute stress and chronic stress affect the brain and trigger the production of hormones, such as cortisol, that control our energy balances and hunger urges. Acute stress can trigger hormone changes that make you not want to eat. If the stress becomes chronic, hormone changes can make you eat more and store more fat.

Environmental Factors

Geography, food availability, transportation, and work environments are environmental factors that can increase your risk for overweight and obesity[7].

  • Geography
    • Where you live may impact your risk of obesity.  In the U.S. the South and the Midwest having the highest level of obesity among adults.  There is also an increase in BMI in rural areas that is which is said to be contributing to approximately 55% of global increases in BMI.  The increase of BMI in rural areas may be due to having farther distances between residences and supermarkets, clinical settings, and recreational opportunities.
  • Food Availability
    • The food that is available in your community may impact your risk of obesity.  Historical data has shown a relationship between the amount of fast food available in a community and the rate of obesity.  The lack of affordable healthy food is termed a “food desert.”  Communities that have been designated as a “food desert” have higher rates of obesity.  The ease and availability of high sugar drinks, large portion sizes, and highly processed snack foods all relate to increased risk of obesity.
  • Transportation
    • How your community is designed may impact your risk of obesity.  A neighborhood purposefully developed to allow for people to be able to walk instead of drive reduces your risk of obesity;  High neighborhood walkability has been found to be associated with decreased prevalence of overweight and obesity.  Neighborhoods that provide recreational facilities, access to sidewalks and paths that remove pedestrians from traffic hazards, and access to parks, have all been reported to be facilitators of physical activity.
  • Work Environment and Advances with Technology
    • Have you considered how jobs have changed with the advances in technology?  From 1960 to 2010, jobs in the U.S. private industry shifted from 50% requiring at least moderate to vigorous physical activity to less than 20% requiring this level of activity intensity[8]. National Health and Nutrition Examination Survey data has documented an association between decreases in work-related energy expenditure and weight gain over the same time period.  The changes in energy expenditure may be due to advances in technology,  an easy example is the use of email to quickly transmit documents rather than walking them to a colleague.

Individual Factors

Although environmental factors have been shown to impact obesity rates, people can have the same environmental factors and still have variances in obesity, fat distribution, and health issues.  Thus, it is important to understand how individual characteristics, such as their genetics,  impact their risk of obesity.

  • Race or Ethnicity
    • Some racial and ethnic minority groups are more likely to have obesity.  Rates of obesity in American adults are highest in blacks, followed by Hispanics, then whites. This is true for men or women. While Asian men and women have the lowest rates of unhealthy BMIs, they may have high amounts of unhealthy fat in the abdomen, which as an increase risk for cardiovascular disease and diabetes. Samoans may be at risk for overweight and obesity because they may carry a DNA variant that is associated with increased BMI.
  • Sex
    • In the United States, obesity is more common in black or Hispanic women than in black or Hispanic men.
    • A person’s sex may also affect the way the body stores fat. For example, men store more unhealthy fat around the abdomen than women.
    • Overweight and obesity is also common in women with polycystic ovary syndrome (PCOS). This is an endocrine condition that causes large ovaries and prevents proper ovulation, which can reduce fertility.
  • Age
    • Many people gain weight as they age. The risk of unhealthy weight gain increases as you age. Adults who have a healthy BMI often start to gain weight in young adulthood and continue to gain weight until 60 to 65 years old, when they tend to start losing weight.
    • Childhood obesity remains a serious problem in the United States and children who have obesity are more likely to have obesity as adults.
  • Genetic Influences
    • The relationships of genetics to obesity has been studied for over 100 years.  Although over 50 genes have been shown to have an association with obesity, in most obese people, no single genetic cause can be identified.  In a study comparing identical and fraternal twins who either grew up together or apart showed that their genetics was more substantially related to their BMI than the environment that they grew up in[9]. Most obesity seems to be multifactorial, that is, the result of complex interactions among many genes and environmental factors.
    • Recent research has been focusing on u
  • Medical Conditions
    • Several genetic syndromes are associated with overweight and obesity, including Prader-Willi syndrome, Bardet-Biedl syndrome, Alström syndrome, and Cohen syndrome
    • Endocrine disorders, such as hypothyroidism and cushing’s syndrome also impact overweight and obesity.
    • Medical problems, such as arthritis, also can lead to decreased activity, which may result in weight gain.
  • Medicines
    • Some medications can lead to weight gain, these include: antipsychotics, antidepressants, antiepileptics, and antihyperglycemics.

Weight Loss Strategies

We know that a majority of our population should implement strategies to lose weight and we know over 50% of Americans have indicated they would like to lose weight.  The Dietary Guidelines for Americans and the Physical Activity Guidelines for Americans provide numerous tips for adjusting diet and exercise to support a health weight, these were explained in Chapters 2 and 3 of this textbook.

Here are additional strategies for weight loss:

Commit to a Weight Loss Plan

As you learned in chapter 1, setting goals is important for behavior change.

  • Make a commitment to lose weight.
    • Explain your “why” for wanting to lose weight
  • Take stock of where you are
    • Take time to assess your current health and lifestyle.
    • Record a food and exercise diary for one week and review the diary to help you  recognize the changes you could make to help you lose weight.
    • The Body Weight Planner is a helpful tool for assisting you in making a personalized calorie and physical activity plans to reach your goal weight within a specific time period and to maintain it afterwards.
  • Make SMART goals
  • Find resources, tools, information, or support that can help you successfully reach your goals.
  • Record your progress and acknowledge or reward your hardwork.

How to assess safe and effective weight loss programs

Would you like additional help and support that may be provided by a structured weight loss program?  With so many different weight loss programs, it may be difficult to choose which program is right for you.

Begin by talking with your healthcare provider.  Share your concern regarding your weight and ask if they can refer you to a weight loss program or specialist.

When reviewing weight loss programs, look for ones that are not just focused on eating a specific food, but rather take more of a holistic view of your overall health and lifestyle habits.

According to the National Institute of Diabetes and Digestive and Kidney Disease, a safe and successful weight-loss programs should include:

  • behavioral treatment, also called lifestyle counseling, that can teach you how to develop and stick with healthier eating and physical activity habits—for example, keeping food and activity records or journals.
  • information about getting enough sleep, managing stress, and the benefits and drawbacks of weight-loss medicines.
  • ongoing feedback, monitoring, and support throughout the program, either in person, by phone, online, or through a combination of these approaches.
  • slow and steady weight-loss goals—usually 1 to 2 pounds per week (though weight loss may be faster at the start of a program).
  • a plan for keeping the weight off, including goal setting, self-checks such as keeping a food journal, and counseling support.

If you would prefer an online program, it should include:

  • organized, weekly lessons, offered online or by podcast, and tailored to your personal goals.
  • support from a qualified staff person to meet your goals.
  • a plan to track your progress on changing your lifestyle habits, such as healthy eating and physical activity, using tools such as cellphones, activity counters, and online journals.
  • regular feedback on your goals, progress, and results provided by a counselor through email, phone, or text messages.
  • the option of social support from a group through bulletin boards, chat rooms, or online meetings.

Avoid weight-loss programs that make any of the following promises:

  • Lose weight without diet or exercise!
  • Lose weight while eating as much as you want of all your favorite foods!
  • Lose 30 pounds in 30 days!
  • Lose weight in specific problem areas of your body!
  • Other warning signs to look out for include
    • very small print, asterisks, and footnotes, which may make it easy to miss important information.
    • before-and-after photos that seem too good to be true.
    • personal endorsements that may be made up.

Dietary Approaches to Weight loss

Tips for healthy eating include:

  • Emphasizes fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products
  • Include a variety of protein foods such as seafood, lean meats and poultry, eggs, legumes (beans and peas), soy products, nuts, and seeds.
  • Reduce saturated fats, trans fats, cholesterol, salt (sodium), and added sugars
  • Stay within your daily calorie needs
    • Replace some higher calorie foods with foods that are lower in calories and   fill you up.
    • Choose smaller portion sizes.  Research shows that people unintentionally consume more calories when faced with larger portions.
      • If eating out where there are large portion sizes, take half of your meal home.
    • When eating a salad, dip your fork into dressing instead of pouring lots of dressing on the salad.
    • When eating out, substitute a broth-based soup or a green lettuce salad for French fries or chips as a side dish.
    • Add more vegetables such as cucumbers, lettuce, tomato, and onions to a sandwich instead of extra meat or cheese.
  • Rethink your drink and drink more water
    • Carry a water bottle with you and refill it throughout the day.
    • Freeze some freezer safe water bottles. Take one with you for ice-cold water all day long.
    • Choose water over sugary drinks.
    • Opt for water when eating out. You’ll save money and reduce calories.
    • Serve water during meals.
    • Add a wedge of lime or lemon to your water. This can help improve the taste and help you drink more water than you usually do.
  • Plan your meals
    • Since high-calorie foods are everywhere, it’s important to take the time to plan ahead to make sure you have healthy options available.
    • Check the restaurant menu and plan your meal ahead of time.
    • Write down everything you eat and drink. It keeps you accountable to yourself!
  • Have healthy snacks ready
    • “Grab-and-go” fruits: apples, oranges, bananas, canned fruit without added sugars, and raisins
    • Washed and chopped fresh vegetables: celery, carrots, and cucumbers
    • Low-fat and fat-free milk products: yogurt without added sugars, milk, and low-fat cheeses
    • Whole-grain crackers and breads
    • Protein choices such as low-fat deli turkey slices or almonds and other nuts and seeds

When eating your favorite comfort foods:

  • Eat them less often. If you normally eat these foods every day, cut back to once a week or once a month.
  • Eat smaller amounts. If your favorite higher-calorie food is a chocolate bar, have a smaller size or only half a bar.
  • Try a lower-calorie version. Use lower-calorie ingredients or prepare food differently. For example, if your macaroni and cheese recipe includes whole milk, butter, and full-fat cheese, try remaking it with non-fat milk, less butter, low-fat cheese, fresh spinach and tomatoes. Just remember to not increase your portion size.


The Dietary Guidelines for Americans stresses the importance of developing a healthy eating pattern.  For some people, it can be helpful to follow a specific diet. If you are interested in following a diet it is important to recognize that even if a particular diet may be successful for one person, it may not be effective for another due to individual differences in genes and lifestyle.  Harvard School of Public Health provides detailed reviews of the following diets for your consideration:

Bariatric Surgery

Weight-loss surgery, also known as bariatric surgery, is an operation that makes changes to the digestive system.  In the United States, surgeons most often perform three types of operations: gastric sleeve, gastric bypass, and adjustable gastric band.  Bariatric surgery may be an option if you have extreme obesity (over 40 BMI) or are at lower levels of obesity (over 30 BMI) but you have serious health problems, such as type 2 diabetes or sleep apnea, related to obesity.  Bariatric surgery can improve many of the medical conditions linked to obesity, especially type 2 diabetes.  Side effects of the surgery may include bleeding, infection, leaking from the surgery site, diarrhea, and blood clots.

A longitudinal study of bariatric surgery (gastic bypass and gastric band) was conducted to understand immediate and long term effects[10].  The study included people who had bariatric surgery between 2005-2009.  Researchers met with the participants before surgery, 30 days after, 6 months after, and then annually until 2015.

Thirty days after bariatric surgery, researchers found that

  • Death rates were low. Only 2.1 percent of participants who had open gastric bypass and 0.2 percent of participants who had laparoscopic gastric bypass died. No participants who had gastric band surgery died.
  • Only 4.1 percent of participants had at least one major bad outcome, such as death, development of blood clots, repeat surgeries, or failure to be released from the hospital.
  • No significant differences in complication risk were found based on the type of gastric bypass procedure.
  • Participants with the highest BMI values had the greatest risk of complications.
  • Participants with a history of deep vein blood clots or sleep apnea had a higher risk of complications.

At the 7-year follow-up, LABS researchers found that

  • Participants lost an average of 28.4 percent of their body weight after gastric bypass surgery and 14.9 percent of their body weight after laparoscopic gastric band surgery.
  • Most participants maintained their weight loss. Three to 7 years after surgery, participants who had gastric bypass surgery regained an average of 3.9 percent of their body weight, and participants who had gastric band surgery regained on average of 1.4 percent of their body weight.
  • High cholesterol was less common after gastric bypass and gastric band surgery.
  • Diabetes and high blood pressure were less common after gastric bypass surgery. Over time, diabetes reoccurred in some patients, but numbers of new cases were low.
  • Alcohol use disorders increased after gastric bypass surgery but not after gastric band surgery.
  • Pain and physical function improved after bariatric surgery.

Body image, eating disorders, and Low Body WEight

Body Image

When you look in the mirror, how do you see yourself and feel about your body (e.g., height, shape, and weight)?  Your body image is what you think, feel, perceive, and behave regarding your body.  Body image is a multidimensional concept that includes[11]:

  • Cognitive: thoughts and beliefs about the body
  • Perceptual: how people perceive the size and shape of their body and body parts
  • Affective: feelings about the body
  • Behavioral: the actions that people perform to check on, tend to, alter, or conceal their body

Factors effecting body image and body image disorders include: BMI, family, social pressures, media, social media, self esteem, chronic illness, depression, and sexual abuse.

A person with a positive body image has a clear and true perception of their body; seeing the various parts of your body as they really are. Body positivity (or body satisfaction) involves feeling comfortable and confident in your body, accepting your natural body shape and size, and recognizing that physical appearance say very little about one’s character and value as a person.

A person with a negative body image or a distorted perception for their body, has feelings of shame, anxiety, and self-consciousness. People who experience high levels of body dissatisfaction feel their bodies are flawed in comparison to others, and they are more likely to suffer from feelings of depression, isolation, low self-esteem, and eating disorders.

Eating Disorders

While there is no single cause of eating disorders, research indicates that body dissatisfaction is the best-known contributor to the development of eating disorders and body dysmorphic disorder.  Body dysmorphic disorder (BDD) is a distressing preoccupation or a markedly excessive concern with one or more perceived or slight defects in physical appearance, associated with significant distress and functional impairment.

Eating disorders are serious and often fatal illnesses that are associated with severe disturbances in people’s eating behaviors and related thoughts and emotions. They are associated with a wide range of adverse psychological, physical, and social consequences. A person with an eating disorder may start out just eating smaller or larger amounts of food, but at some point, their urge to eat less or more spirals out of control. Severe distress or concern about body weight or shape, or extreme efforts to manage weight or food intake, also may characterize an eating disorder.

Eating disorders are real, treatable medical illnesses. They frequently coexist with other illnesses such as depression, substance abuse, or anxiety disorders. Other symptoms can become life-threatening if a person does not receive treatment, which is reflected by anorexia being associated with the highest mortality rate of any psychiatric disorder.

Anorexia Nervosa

Many people with anorexia nervosa see themselves as overweight, even when they are clearly underweight. Eating, food, and weight control become obsessions. People with anorexia nervosa typically weigh themselves repeatedly, portion food carefully, and eat very small quantities of only certain foods. Some people with anorexia nervosa also may engage in binge eating followed by extreme dieting, excessive exercise, self-induced vomiting, or misuse of laxatives, diuretics, or enemas.

Symptoms of anorexia nervosa include:

  • Extremely low body weight
  • Severe food restriction
  • Relentless pursuit of thinness and unwillingness to maintain a normal or healthy weight
  • Intense fear of gaining weight
  • Distorted body image and self-esteem that is heavily influenced by perceptions of body weight and shape, or a denial of the seriousness of low body weight
  • Lack of menstruation among girls and women.
  • Some who have anorexia nervosa recover with treatment after only one episode. Others get well but have relapses. Still others have a more chronic, or long-lasting, form of anorexia nervosa, in which their health declines as they battle the illness.

Other symptoms and medical complications may develop over time, including:

  • Thinning of the bones (osteopenia or osteoporosis)
  • Brittle hair and nails
  • Dry and yellowish skin
  • Growth of fine hair all over the body (lanugo)
  • Mild anemia, muscle wasting, and weakness
  • Severe constipation
  • Low blood pressure, or slowed breathing and pulse
  • Damage to the structure and function of the heart
  • Brain damage
  • Multi-organ failure
  • Drop in internal body temperature, causing a person to feel cold all the time
  • Lethargy, sluggishness, or feeling tired all the time
  • Infertility.

Bulimia Nervosa

People with bulimia nervosa have recurrent and frequent episodes of eating unusually large amounts of food and feel a lack of control over these episodes. This binge eating is followed by behavior that compensates for the overeating such as forced vomiting, excessive use of laxatives or diuretics, fasting, excessive exercise, or a combination of these behaviors.

Unlike anorexia nervosa, people with bulimia nervosa usually maintain what is considered a healthy or normal weight, while some are slightly overweight. But like people with anorexia nervosa, they often fear gaining weight, desperately want to lose weight, and are intensely unhappy with their body size and shape. Usually, bulimic behavior is done secretly because it is often accompanied by feelings of disgust or shame. The binge eating and purging cycle can happen anywhere from several times a week to many times a day.

Other symptoms include:

  • Chronically inflamed and sore throat
  • Swollen salivary glands in the neck and jaw area
  • Worn tooth enamel, and increasingly sensitive and decaying teeth as a result of exposure to stomach acid
  • Acid reflux disorder and other gastrointestinal problems
  • Intestinal distress and irritation from laxative abuse
  • Severe dehydration from purging of fluids
  • Electrolyte imbalance—too low or too high levels of sodium, calcium, potassium, and other minerals that can lead to a heart attack or stroke.

Binge-Eating Disorder

People with binge-eating disorder lose control over their eating. Unlike bulimia nervosa, periods of binge eating are not followed by compensatory behaviors like purging, excessive exercise, or fasting. As a result, people with binge-eating disorder often are overweight or obese. People with binge-eating disorder who are obese are at higher risk for developing cardiovascular disease and high blood pressure. They also experience guilt, shame, and distress about their binge eating, which can lead to more binge eating.

Low Body Weight (underweight)

Because more people experience excess body fat, the focus up to this point has been on health concerns related to overweight and obesity. However, fat is an essential component to a healthy body and insufficient fat reserves can cause health issues.  It is estimated that 1.6% of U.S. adults aged 20 and over are underweight. Poor nutrition or underlying health conditions can result in adults being underweight.  A healthy body fat percentage for men is 10-22% body fat (minimum required is 3-5% fat) and women is 20-32% body fat (minimum required is 8-12%). Using a BMI, if your BMI is less than 18.5, it falls within the underweight range.

Persons who are underweight may experience:

  • Osteoporosis
  • Skin, hair, and teeth problems
  • Immune System disorders (get sick more)
  • Low energy (tired or fatigued all the time)
  • Reproductive disorders:  Irregular menstrual cycle and premature births
  • Respiratory disorders
  • Slow or impaired growth due to lack of nutrients
  • Mental health issues such as Depression
  • Increased mortality from external causes like accidents, injuries, and suicide[12]

Key Takeaways for Chapter 4

  • Fat plays an important role in our health.
  • The BMI is the standard measurement used to define healthy weight.
  • BMI does not measure body composition or body fatness, it only measures body size.
  • Obesity is an epidemic.
  • Obesity is caused by many factors including lifestyle habits/choices, environment, and individual factors, such as genetics.
  • Having a healthy diet pattern and incorporating physical activity and exercise are important for a healthy weight.
  • Both overweight/obesity and underweight have negative health implications

Media Attributions

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  8. Church, T. S., Thomas, D. M., Tudor-Locke, C., Katzmarzyk, P. T., Earnest, C. P., Rodarte, R. Q., Martin, C. K., Blair, S. N., & Bouchard, C. (2011). Trends over 5 decades in U.S. occupation-related physical activity and their associations with obesity. PloS one, 6(5), e19657.
  9. Stunkard, A. J., Harris, J. R., Pedersen, N. L., & McClearn, G. E. (1990). The Body-Mass Index of Twins Who Have Been Reared Apart. New England Journal of Medicine, 322(21), 1483–1487.
  10. Long-term Study of Bariatric Surgery for Obesity: LABS. (2021, December 9). National Institute of Diabetes and Digestive and Kidney Diseases.
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  12. Roh, L., Braun, J., Chiolero, A., Bopp, M., Rohrmann, S., Faeh, D., & Swiss National Cohort Study Group (2014). Mortality risk associated with underweight: a census-linked cohort of 31,578 individuals with up to 32 years of follow-up. BMC public health, 14, 371.


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