Body mass index
Food Nutrition · Public Health · Epidemiology
Say it: BOD-ee MAS IN-deks
Body mass index is a screening measure that relates body weight to height, found by dividing weight in kilograms by height in meters squared.
Also: BMI
Definition
What is body mass index?
Body mass index, or BMI, is a quick way to relate a person's weight to their height. To work it out, take a person's weight in kilograms and divide it by their height in meters multiplied by itself, giving a number in kilograms per square meter. For adults, the World Health Organization and the US Centers for Disease Control and Prevention use the same cut-offs: below 18.5 is underweight, 18.5 to under 25 is the healthy range, 25 to under 30 is overweight, and 30 or more is obesity, which is further divided into three classes.
BMI is popular because it needs only a scale and a measuring tape, and across populations higher values go with a greater risk of heart disease, type 2 diabetes and some cancers. It is a screening tool, not a diagnosis. It does not measure body fat directly, cannot tell fat from muscle and bone, and says nothing about where fat is carried, so a very muscular person can score as overweight. Waist circumference and other measures are often used alongside it.
Children and teenagers are assessed differently, by comparing their BMI with others of the same age and sex on growth charts, because body composition changes as they grow.
Related
Terms that go with it
- 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.
- MacronutrientA macronutrient is a nutrient needed in large amounts, namely carbohydrate, protein or fat, which together supply energy and the raw materials for growth.
- 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.
- HypertensionHypertension is a long-term condition in which the pressure of blood against artery walls stays higher than normal, straining the heart and vessels.
- Public healthPublic health is the science and practice of preventing disease and injury and promoting health across whole communities rather than individual patients.
- PrevalencePrevalence is the share of a population living with a particular disease or condition, either at one point in time or across a set period.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- CDC: Adult BMI Categories
- CDC: About Body Mass Index (BMI)
- WHO: Obesity and overweight fact sheet
- NCI Dictionary of Cancer Terms: body mass index
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