Obesity in America 2021


Over the past several decades the obesity rate in America has increased. In fact, the World Health Organization (WHO) has found that obesity around the world tripled since 1975. According to a WHO report from 2016, there were 1.9 billion overweight or obese adults (aged 18+) worldwide and 340 million overweight or obese children (ages 5-18). In 2020, WHO reported 39 million children under the age of five were overweight or obese.

The obesity epidemic is a well-known and well-documented health crisis. Excess weight is a risk factor that can lead to health issues including heart disease, type 2 diabetes, certain types of cancer, stroke, and premature death. More than two-thirds of American adults are overweight or obese and at risk. What can personal trainers do to help with obesity prevention? Educate yourself and your clients.


There are many factors that can cause obesity. The Centers for Disease Control and Prevention (CDC) notes that obesity is a complex disease, influenced by multiple factors. According to the CDC, genetics, behaviors, education and skills, food marketing and promotion, and community and social factors may contribute to an individual's health status. The following are examples of specific risk factors for overweight and obesity:

  • Food intake and diet
  • Access to safe places for physical activity
  • Level of activity
  • Family prevalence of overweight
  • Access to health care
  • Health conditions and medications
  • Access to healthy food
  • Knowledge of healthy food choices
  • Stress
  • Emotional factors
  • Poor sleep


Adult obesity rates in the US vary based on age group. The highest obesity rate in adults is for the group aged 40 to 59, followed by adults over 60, and lastly 20- to 39-year-olds.

The adult obesity rate also varies by race. The CDC reported the following:

  • Non-Hispanic black adults had the highest prevalence of obesity at about 38%.
  • Around 33% of Hispanic adults are obese.
  • Close to 29% of non-Hispanic white adults are obese.
  • Fewer than 20% of Asian American adults are considered obese.


There is no clear answer to what is a healthy weight for men or what is a healthy weight for women. Why? Because just like obesity, healthy weight is affected by multiple factors. Age, muscle mass, fat density, and growth curve (for children) influence body weight and must be taken into account when deciding what is a healthy weight.

One common measure is the Body Mass Index or BMI. But, this method is inaccurate for individuals with higher muscle mass but, given current stats, is reliable for most of the population. 

BMI equation is as follows:

[weight (lbs) / (height (in) x height (in))] x 703 

Consider one who weighs 145 pounds and stands 56 inches tall.

[145 / (56 x 56)] x 703

[145 / 3136] x 703

[0.04623] x 703

BMI = 32.5

There are also online calculators and apps that make finding BMI easier. Once BMI has been calculated, compare the results to this adult BMI chart to determine weight status.

BMI Rating

Under 18.5

18.5 - 24.9

25 - 29.9

30 and above


Healthy weight



According to the chart, our sample client is in the obese category.


Current Rates of Obesity in Children

A 2015 study in the Journal of Family Medicine and Primary Care paints a regretful picture of the consequences of childhood obesity. The study says,

“Childhood obesity can profoundly affect children's physical health, social, and emotional well-being, and self esteem. It is also associated with poor academic performance and a lower quality of life experienced by the child. Many co-morbid conditions like metabolic, cardiovascular, orthopedic, neurological, hepatic, pulmonary, and renal disorders are also seen in association with childhood obesity.”


Of course, childhood obesity prevalence, like adult obesity, is also affected by multiple factors. Genetics and behaviors play a role, but parents and caregivers' influence on children is also a major factor in childhood obesity. Preventing weight gain and promoting a healthy weight are vital as children grow. Most studies find that an obese child will grow up to be an obese adult. 


Children's weight status is based on a growth curve. For kids and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age. 

To find a client's BMI-for-age, use the following equation:

[weight (lbs) x 703 / (height (in) x height (in))]

A BMI example for a 15-year-old male who weighs 95 pounds and stands 53 inches tall 

[95 x 703 / (53 x 53)]

[66785 / 2809]

BMI = 23.77

This number is then found on the CDC data table of BMI-for-age Chart. Our sample client falls in the 85th percentile and therefore is in the healthy range. BMI data for children should be considered in the context of the growth curve and other factors such as lean body mass.


Overweight and obesity increase the risk for chronic disease. Common conditions linked to unhealthy weight include:

  • Type 2 diabetes
  • High blood pressure
  • Sleep apnea
  • Heart disease
  • Stroke
  • High blood glucose levels
  • High triglycerides
  • Low HDL
  • Fatty liver disease
  • Cardiovascular disease
  • Some cancers

Obesity-related healthcare costs are $147 billion per year. Employees with obesity-related illnesses reduce workforce productivity and cost US companies anywhere from $3.4 billion to $6.4 billion annually. The burden of the obesity epidemic is heavy on all accounts.


The National Institute of Diabetes and Digestive and Kidney Diseases suggests the following treatments for overweight and obesity:

  • Healthy eating plan
  • Regular physical activity
  • Weight-management programs
  • Weight-loss medicines
  • Weight-loss devices
  • Bariatric surgery
  • Special diets
  • Improved habits

Genetics plays a small role in overall health, only about 25%. Therefore, obesity is often referred to as a lifestyle-related disease. That said, behavior change is one of the most effective, albeit difficult, ways to reverse obesity and maintain good overall health.

Clients must be emotionally, mentally, and financially capable of making behavior changes. All too often a client suffering from being overweight was forced to see a doctor, diet, or join an exercise program without being ready to. As a result, they fail to lose weight or gain back whatever they lost plus some.

When planning a weight loss program for a client, it is key that they understand the health risks associated with excess weight and are prepared to make necessary changes. A sound weight loss plan should include regular physical activity, healthy food choices, behavior modification, and data tracking.


Small adjustments in routine can lead to major improvements in health. For example, adding a 10-minute walk to a lunchtime routine can add up to nearly an hour of physical activity each week. Encouraging clients to take up a hobby such as gardening or woodworking can also increase physical activity and dramatically improve their quality of life.

Resistance training is also key to losing weight and maintaining a healthy body composition. Start slowly by giving clients simple exercises they can do at their desk, before they shower, or while they're on their lunchtime walk.


Diet is most often the hardest obstacle to overcome (the subject for another article, to be sure). The best way to approach diet is through small gradual shifts. For example, a client might benefit from learning about healthier alternatives to their favorite foods. You might then work with them to reduce portion sizes or teach them how to listen to their body to decide when to eat. Once they see health improvements, they may decide to follow a meal plan. 

Making gradual, small changes helps clients develop habits over time, not overnight, which is much more sustainable than an all-or-nothing approach.


Finally, because weight loss is a gradual process, tracking health and fitness measures is vital to keeping clients motivated and dedicated to improving their health. Track as many of the following metrics as possible to get a better picture of a client's overall health and progress in the weight loss program:

  • BMI
  • Lean body mass
  • Sleep patterns
  • Dietary intake
  • Physical activity levels
  • Heart rate
  • Blood pressure
  • Strength
  • Flexibility
  • Cardiovascular endurance

Interested in joining the fight against the obesity trend? Consider getting a career in exercise science. From the comfort of your home, Lionel University offers several exercise science degree programs. What’s better, you can earn a living as a fitness professional while attending Lionel since you’ll get a personal training certification right away.

Lionel programs include associates, bachelors, and masters degree exercise science programs- all of which are online, which means you can study at the comfort of your own home and during the time that works for you. And, financial aid is available. All of this makes pursuing a dream as a fitness professional possible. Contact Lionel today with more questions.