Obesity is a complex disease involving an excessive amount of body fat. Obesity isn’t just a cosmetic concern. It’s a medical problem that increases the risk of other diseases and health problems, such as heart disease, diabetes, high blood pressure and certain cancers.
There are many reasons why some people have difficulty losing weight. Usually, obesity results from inherited, physiological and environmental factors, combined with diet, physical activity and exercise choices.
The good news is that even modest weight loss can improve or prevent the health problems associated with obesity. A healthier diet, increased physical activity and behavior changes can help you lose weight. Prescription medications and weight-loss procedures are additional options for treating obesity.
Symptoms
Body mass index (BMI) is often used to diagnose obesity. To calculate BMI, multiply weight in pounds by 703, divide by height in inches and then divide again by height in inches. Or divide weight in kilograms by height in meters squared.
For most people, BMI provides a reasonable estimate of body fat. However, BMI doesn’t directly measure body fat, so some people, such as muscular athletes, may have a BMI in the obesity category even though they don’t have excess body fat.
Many doctors also measure a person’s waist circumference to help guide treatment decisions. Weight-related health problems are more common in men with a waist circumference over 40 inches (102 centimeters) and in women with a waist measurement over 35 inches (89 centimeters).
Causes
Although there are genetic, behavioral, metabolic and hormonal influences on body weight, obesity occurs when you take in more calories than you burn through normal daily activities and exercise. Your body stores these excess calories as fat.
In the United States, most people’s diets are too high in calories — often from fast food and high-calorie beverages. People with obesity might eat more calories before feeling full, feel hungry sooner, or eat more due to stress or anxiety.
Many people who live in Western countries now have jobs that are much less physically demanding, so they don’t tend to burn as many calories at work. Even daily activities use fewer calories, courtesy of conveniences such as remote controls, escalators, online shopping and drive-through banks.
Complications
People with obesity are more likely to develop a number of potentially serious health problems, including:
Heart disease and strokes. Obesity makes you more likely to have high blood pressure and abnormal cholesterol levels, which are risk factors for heart disease and strokes.
Type 2 diabetes. Obesity can affect the way the body uses insulin to control blood sugar levels. This raises the risk of insulin resistance and diabetes.
Certain cancers. Obesity may increase the risk of cancer of the uterus, cervix, endometrium, ovary, breast, colon, rectum, esophagus, liver, gallbladder, pancreas, kidney and prostate.
Digestive problems. Obesity increases the likelihood of developing heartburn, gallbladder disease and liver problems.
Sleep apnea. People with obesity are more likely to have sleep apnea, a potentially serious disorder in which breathing repeatedly stops and starts during sleep.
Osteoarthritis. Obesity increases the stress placed on weight-bearing joints, in addition to promoting inflammation within the body. These factors may lead to complications such as osteoarthritis.
Severe COVID-19 symptoms. Obesity increases the risk of developing severe symptoms if you become infected with the virus that causes coronavirus disease 2019 (COVID-19). People who have severe cases of COVID-19 may require treatment in intensive care units or even mechanical assistance to breathe.
Diagnosis
These exams and tests generally include:
Taking your health history. Your doctor may review your weight history, weight-loss efforts, physical activity and exercise habits, eating patterns and appetite control, what other conditions you’ve had, medications, stress levels, and other issues about your health. Your doctor may also review your family’s health history to see if you may be predisposed to certain conditions.
A general physical exam. This includes measuring your height; checking vital signs, such as heart rate, blood pressure and temperature; listening to your heart and lungs; and examining your abdomen.
Calculating your BMI. Your doctor will check your body mass index (BMI). A BMI of 30 or higher is considered obesity. Numbers higher than 30 increase health risks even more. Your BMI should be checked at least once a year because it can help determine your overall health risks and what treatments may be appropriate.
Measuring your waist circumference. Fat stored around the waist, sometimes called visceral fat or abdominal fat, may further increase the risk of heart disease and diabetes. Women with a waist measurement (circumference) of more than 35 inches (89 centimeters) and men with a waist measurement of more than 40 inches (102 centimeters) may have more health risks than do people with smaller waist measurements. Like the BMI measurement, waist circumference should be checked at least once a year.
Checking for other health problems. If you have known health problems, your doctor will evaluate them. Your doctor will also check for other possible health problems, such as high blood pressure, high cholesterol, underactive thyroid, liver problems and diabetes.
Treatment
The goal of obesity treatment is to reach and stay at a healthy weight. This improves overall health and lowers the risk of developing complications related to obesity.
You may need to work with a team of health professionals — including a dietitian, behavioral counselor or an obesity specialist — to help you understand and make changes in your eating and activity habits.
The initial treatment goal is usually a modest weight loss — 5% to 10% of your total weight. That means that if you weigh 200 pounds (91 kilograms), you’d need to lose only about 10 to 20 pounds (4.5 to 9 kilograms) for your health to begin to improve. However, the more weight you lose, the greater the benefits.
All weight-loss programs require changes in your eating habits and increased physical activity. The treatment methods that are right for you depend on your obesity severity, your overall health and your willingness to participate in your weight-loss plan.