Understanding Obesity: What Is It And How It Can Affect The Body

The obesity epidemic is on the rise in the US. According to The Centers for Disease Control and Prevention (CDC), the US adult obesity prevalence was 42.4%¹ between  2017-2018, which was the first time the national rate had passed the 40% mark.  According to Trust for America’s Health, since 2008, the national adult obesity rate increased 26%, highlighting just how severe the US obesity crisis is.

Despite the growing number of obese Americans, many people still don't understand what obesity is and how it can affect their bodies. Obesity is a complex disease that is characterized by an excessive amount of body fat, generally caused by eating too much and moving too little. It's important to note that obesity is not just a cosmetic concern. It is a medical problem that can lead to a range of other health problems and diseases if left untreated.

When we consume a high amount of energy, specifically fat and carbohydrates, without burning this excess energy through physical activity, the surplus energy is stored in the body as fat. While certain genetic conditions such as Prader-Willi Syndrome² can make losing weight difficult, most cases of obesity are caused by lifestyle and environmental factors.

Overweight vs obese: What's the difference?

Being overweight and obese are both defined as having more body fat than what is considered healthy. Both conditions are caused by a variety of factors including:

• Unhealthy lifestyle habits

• Unhealthy environments

• Age

• Family history and genetics

• Race or ethnicity

• Sex

While the similarities can make it difficult to differentiate the two conditions, someone who is obese has a higher percentage of body fat (BMI of 30 or more) compared to someone who is overweight (BMI between 25-29.9).

How is obesity diagnosed?

Obesity is diagnosed using body mass index (BMI). BMI is a measure of body fat based on height and weight. If your BMI is 30 or higher, it falls within the obesity range.

Obesity is divided into classes:

• Class 1: BMI of 30 to < 35

• Class 2: BMI of 35 to < 40

• Class 3: BMI of 40 or higher (sometimes referred to as severe obesity)

According to The World Journal of Gastroenterology, there are four phenotypes of obesity³ based on body fat composition and distribution:

• Normal weight obesity

• Metabolically obese normal weight

• Metabolically healthy obese

• Metabolically unhealthy obese

Normal weight obesity

This is a condition in which a person has  BMI under 30 but an increased body fat percentage. As a result, these individuals are at a greater risk of developing chronic diseases.

Metabolically obese normal weight

This phenotype refers to individuals with a normal weight and BMI who display some metabolic disturbances typical of obese people. This increases the risk of developing metabolic syndrome in the same way as regular obesity.

Metabolically healthy obese

This is defined as an obese person who does not present any metabolic disorder or cardiovascular disease, including conditions such as type 2 diabetes and hypertension.

Metabolically unhealthy obese

Defined as an obese person who presents with obesity accompanied by metabolic risk factors such as high blood pressure, high fasting blood sugar, and diabetes.

Tests for obesity

To diagnose obesity, your doctor will perform a physical exam. They may also perform a variety of other tests to assess your health risk, including the following:

• Reviewing your weight history – Your doctor may review your weight history, efforts to lose weight, physical activity, exercise habits, eating habits, appetite control, past conditions, and a variety of other factors that contribute to your weight.

• General physical exam – A physical health exam includes measuring your height, checking your vital signs such as your heart rate, blood pressure, and temperature. The doctor will also listen to your heart and lungs, and examine your abdomen.

• BMI calculation – BMI is a common way to diagnose obesity. A BMI of 30 or higher is considered obese. The higher the BMI, the greater the health risks.

• Measuring your waist circumference – Visceral fat, which is an increase in the fat around the waist, may further increase health risks for individuals. A waist circumference of more than 35 inches in women 45 inches in men results in increased risk compared to those with smaller waists.

• Checking for other health issues – If you're experiencing health problems, your doctor will also check for other issues, such as high blood pressure, high cholesterol, liver problems, and diabetes.

What are the complications of obesity?

Everyone needs body fat to survive  – it provides energy, heat insulation, and supports other bodily functions. However, too much fat can cause mild to severe health complications.

Being overweight and obese are the fifth leading risk of death globally⁴. At least 2.8 million adults die each year from these conditions, according to the European Association for the Study of Obesity (EASO) which states that worldwide obesity has nearly doubled since 1980.

Health issues associated with obesity include:

• Digestive problems – Obesity increases the likelihood of developing certain digestive problems, such as heartburn, gallbladder disease, and liver problems.

• Heart disease and stroke – Being obese can increase your risk of heart disease and stroke because it leads to risk factors such as high blood pressure and abnormal cholesterol levels.

• Type 2 diabetes – There are three main types of diabetes: gestational, type 1, and type 2. Type 2 diabetes is an impairment in the way the body regulates and uses sugar as fuel. Being overweight is a key determining factor in whether you develop type 2 diabetes.

• Sleep apnea – This is a potentially serious sleep disorder in which breathing repeatedly starts and stops. There are three types of sleep apnea: obstructive sleep apnea, central sleep apnea, and complex sleep apnea syndrome. One of the main components contributing to sleep apnea is obesity⁵.

• Osteoarthritis – This is the most common form of arthritis. Osteoarthritis occurs when the protective cartilage that cushions the ends of the bones wears down over time. This type of arthritis can damage any joint but is most commonly found to affect the hands, knees, and spine. Since obesity increases the stress placed on weight-bearing joints and increases the inflammation in the body, osteoarthritis is more likely to occur.

• Certain cancers – Obesity may increase your risk of certain cancers, including the uterus, cervix, endometrium, ovary, breast, colon, rectum, and more. 

When should you see a doctor?

Obesity often comes with a variety of symptoms. For instance, many obese individuals experience back and joint pain due to the added pressure and inflammation caused by carrying excess weight.

They may also experience shortness of breath, known as dyspnoea. This can be due to certain physiological variables⁶ such as reduced lung volume subdivisions and chest wall compliance as a result of accumulated adipose tissue.

Other symptoms of obesity include intolerance to heat, infections in skin folds, and fatigue.

Some people have more minor symptoms of obesity that cause only mild discomfort, while others have more severe symptoms that have a serious negative impact on their quality of life.

The following signs can indicate that you should contact your doctor for medical advice:

Your BMI indicates you are obese

While obesity can cause various health complications, it is reversible. Therefore, you should contact your doctor when your BMI indicates you are obese, even if you don't have any symptoms associated with obesity.

Seeing a doctor who can put you on the right track to lower your BMI down is essential to better health.

Your weight is affecting your physical health

If your weight is affecting your physical health, and you have symptoms such as fatigue, blurred vision, joint pain, and shortness of breath, it's best to visit a doctor to address the underlying cause.

Your weight is affecting your emotional health

Studies show that about 43% of adults⁷ with depression are obese, according to the CDC. If you find that your weight is affecting your emotional health, it's best to seek help from a doctor.

The lowdown

Obesity is a reality for many Americans, and living with obesity can cause a variety of health problems and reduce your quality of life. The good news is that obesity is one of the most preventable diseases⁸ through the right diet, exercise, and a healthy lifestyle.

If you are overweight or obese, even if you don’t have any symptoms of obesity, you should visit your doctor for an assessment.  It's especially important to visit a doctor if you have a BMI over 30 and if your weight affects your physical or mental health.