Obesity

Obesity

What is obesity?

Body mass index (BMI) is a calculation that takes a person’s weight and height into account to measure body size.

In adults, obesity is defined as having a BMI of 30.0 or moreTrusted Source, according to the Centers for Disease Control and Prevention (CDC).

Obesity is associated with a higher risk for serious diseases, such as type 2 diabetes, heart disease, and cancer.

Obesity is common. 

But BMI isn’t everything. It has some limitations as a metric.

According to the CDCTrusted Source: “Factors such as age, sex, ethnicity, and muscle mass can influence the relationship between BMI and body fat. Also, BMI doesn’t distinguish between excess fat, muscle, or bone mass, nor does it provide any indication of the distribution of fat among individuals.”

Despite these limitations, BMI continues to be widely used as a way to measure body size.

How is obesity classified?

The following classesTrusted Source are used for adults who are at least 20 years old:

classesTrusted Source  of  BMI

What is childhood obesity?

For a doctor to diagnose a child over 2 years old or a teen with obesity, their BMI has to be in the 95th percentileTrusted Source for people of their same age and biological sex:

childhood percent

What causes obesity?

Eating more calories than you burn in daily activity and exercise — on a long-term basis — can lead to obesity. Over time, these extra calories add up and cause weight gain.

But it’s not always just about calories in and calories out, or having a sedentary lifestyle. While those are indeed causes of obesity, some causes you can’t control.

Common specific causes of obesity include:

• genetics, which can affect how your body processes food into energy and how fat is stored
• growing older, which can lead to less muscle mass and a slower metabolic rate, making it easier to gain weight
• not sleeping enough, which can lead to hormonal changes that make you feel hungrier and crave certain high-calorie foods
• pregnancy, as weight gained during pregnancy may be difficult to lose and might eventually lead to obesity

Certain health conditions can also lead to weight gain, which may lead to obesity. These include:

• polycystic ovary syndrome (PCOS), a condition that causes an imbalance of female reproductive hormones
• Prader-Willi syndrome, a rare condition present at birth that causes excessive hunger
• Cushing syndrome, a condition caused by having high cortisol levels (the stress hormone) in your system
• hypothyroidism (underactive thyroid), a condition in which the thyroid gland doesn’t produce enough of certain important hormones
• osteoarthritis (OA) and other conditions that cause pain that may lead to reduced activity

The following sources have been used and credited to their respective owners:
https://www.healthline.com/ 

https://www.cdc.gov/