Obesity
Medicine · Food Nutrition · Public Health
Say it: oh-BEE-sih-tee
Obesity is a chronic disease in which excess body fat builds up enough to harm health, defined in adults as a body mass index of 30 or more.
Definition
What is obesity?
Obesity is an excess of body fat large enough to raise the risk of illness and early death. In adults it is usually screened for with body mass index (BMI), which compares weight with the square of height, in kilograms per square meter: 25 or more counts as overweight and 30 or more as obesity. Because BMI does not show where fat is stored, waist circumference is often measured too, since fat around the abdominal organs carries the greatest risk. Children are assessed against growth references for their age and sex.
At its simplest, obesity results from taking in more energy than the body uses over a long period, but many factors shape that balance: genes, which strongly influence body weight; hormones such as leptin that signal fullness to the hypothalamus; sleep, stress and some medicines; and surroundings full of cheap, energy-dense food with little need for physical activity. It is a major risk factor for type 2 diabetes, heart disease, stroke, fatty liver disease, sleep apnea, osteoarthritis and several cancers.
More than a billion people live with obesity worldwide, and rates have risen sharply since 1990. Treatment combines changes in diet and activity with, for many people, medicines such as GLP-1 receptor agonists or weight-loss (bariatric) surgery.
Word parts
Where does the word “obesity” come from?
- obes-
- fat, stout; literally having eaten oneself fatLatin obesus, from ob-, over + edere, to eat
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Terms that go with it
- Body mass indexBody mass index is a screening measure that relates body weight to height, found by dividing weight in kilograms by height in meters squared.
- Metabolic syndromeMetabolic syndrome is a cluster of linked risk factors, including a large waist, high blood pressure, high blood sugar and abnormal blood fats.
- Diabetes mellitusDiabetes mellitus is a chronic disease in which blood glucose stays too high because the body makes too little insulin or cannot use it well.
- CalorieA calorie is a unit of energy, the heat needed to warm one gram of water by one degree Celsius; food energy is given in kilocalories, often written Calories.
- Noncommunicable diseaseA noncommunicable disease is a long-lasting illness, such as heart disease, cancer or diabetes, that does not pass from one person to another.
- Risk factorA risk factor is a trait, exposure or behavior linked to a higher chance of developing a particular disease, injury or other health problem.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- WHO fact sheet: Obesity and overweight
- CDC: About Obesity
- NHLBI: What Are Overweight and Obesity?
- MSD Manual Consumer Version: Obesity
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