Many people use the words “obese” and “overweight” casually and interchangeably. But they’re medical terms with very different meanings.
Overweight and obese both define bodies that carry more fat. Today, the National Institutes of Health (NIH) considers more than one-third of Americans obese.
Excess fat is responsible for a variety of chronic health conditions. These include heart disease, diabetes, and respiratory problems.
Becoming overweight or obese is the second-leading cause of preventable death in the United States, says NIH.
It’s vital to understand your weight and how it might affect your health. Read on for different ways that doctors define and measure a person’s excess fat. And learn more about the health complications and causes of obesity.
What is “Overweight” and “Obese”
The Centers for Disease Control (CDC) defines “overweight” as having excess fat. It causes someone to weigh more than recommended for their height and age, putting their health at risk.
Obesity is a condition in which someone is severely overweight, which puts their health at an even greater risk.
There are multiple ways that doctors measure when someone becomes obese or overweight. They include:
Body mass index (BMI)
BMI is a number you can calculate from a person’s weight and height. Most people use it to screen for weight categories that may lead to health problems. It provides a rough estimate of the amount of fat in the body.
BMI ranges fall into several categories. According to the CDC, people with a BMI of 18.5 or less are underweight. Those who fall between 18.5 to 24.9 are normal weight.
Those between 25 and 29.9 fall within the overweight range. Health professionals characterize individuals as obese if they have a BMI greater than 30.
Waist size
Measuring waist size helps to assess the amount of abdominal fat a person has. Too much fat around the waist can increase the risk of health problems. It can do this even if your BMI is in the normal range.
Men with a waist measurement over 40 inches and women with a measurement over 35 inches are at risk for health problems related to obesity.
Body fat percentage
This measures how much fat makes up your body weight. It’s a more accurate way to assess body fat than BMI is. This is because it considers how much of your body is muscle, bone, and organs.
Other ways health professionals can calculate whether a person is overweight or obese are waist-to-hip ratio, clinical evaluation, and blood tests.
Calculating Your Body Mass Index
You calculate your body mass index by dividing your weight in kilograms by your height in meters squared. Use our BMI chart to find your range.
Body mass index, however, can prove misleading because it doesn’t directly calculate body fat. If your body mass index is outside the normal range, discuss this with your health care provider. They can help you decide if you need to make lifestyle changes.
Doctors measure your weight and height and then use a BMI chart or calculator to find your BMI number. If your BMI is 25 to 29.9, it falls within the overweight range. If it’s 30 or higher, it’s considered obese.
Calculating Your Fat Percentage
Several methods measure body fat percentage. These include skinfold measurements, bioelectrical impedance, and more sophisticated techniques like DEXA scans. Doctors select a method based on its accuracy and convenience.
Finding Your Waist Measurement
A doctor will use a tape measure to find the distance around your waist. Generally, doctors consider a waist size of more than 40 inches for men and more than 35 inches for women high.
What Health Complications Can Result from These Conditions?
People who are obese are at risk of developing more than 40 different medical conditions. These are among the most common:
Heart disease and stroke. Excess body weight can lead to increased blood pressure, high cholesterol, and atherosclerosis. All of these increase the risk of heart disease and stroke.
Type 2 diabetes and insulin resistance. Becoming overweight is a primary risk factor for developing type 2 diabetes. Type 2 diabetes is a condition in which the body can’t control blood sugar levels.
Certain cancers. A link exists between obesity and an increased risk of certain types of cancer. These include breast, colon, endometrial, kidney, and esophageal cancer.
Osteoarthritis. Extra weight can put more pressure on joints and cartilage. This can cause them to wear away, leading to osteoarthritis, a common joint condition.
Sleep Apnea. Overweight individuals are more likely to have sleep apnea, a potentially serious sleep disorder in which breathing stops and starts.
Gallbladder disease. Obesity can increase the likelihood of developing gallstones and gallbladder disease.
Hypertension. Excess weight is a significant risk factor for high blood pressure. This can lead to other cardiovascular issues.
Other complications from becoming overweight or obese include fatty liver disease, gout, and mental health issues. They also can include respiratory problems and skin conditions.
What Causes Obesity?
- Age. As you age, hormonal changes and a less active lifestyle can increase your risk of obesity. Your muscle mass tends to decrease with age. This lower muscle mass leads to a decrease in metabolism, resulting in weight gain.
- Chemical changes. Research indicates that people who stop smoking often gain weight. Certain medications can also result in weight gain and a risk of obesity.
- Genetics. Some people have a “faulty” gene that leads them to overeat and consume too many fatty foods. This often results in obesity.
- Not enough exercise. Exercise helps you burn calories and, therefore, fat. It also changes how your body processes food. Sufficient and consistent exercise lowers the risk of obesity.
- Psychological factors. Many people eat in response to negative emotions like boredom, sadness, or stress. This emotional eating can lead to overeating, particularly of high-calorie comfort foods.
- Sleep deprivation. Numerous studies have shown that sleeping too little doubles your risk of obesity. Sleep deprivation results in hormonal changes that can affect your appetite and metabolism.
- An unhealthy diet. Consuming too many calories and eating larger portion sizes can have a major impact on your health.
Editor's Note: This article was originally published on , and was last reviewed on .