Table of ContentsView AllTable of ContentsBMI AccuracyBMI InaccuracyOther Ways to Assess HealthA Healthy BMI
Table of ContentsView All
View All
Table of Contents
BMI Accuracy
BMI Inaccuracy
Other Ways to Assess Health
A Healthy BMI
While there is a noted correlation between high BMI and obesity-related health risks, such as cardiovascular disease and type 2 diabetes, BMI has flaws and is not meant to be a diagnostic tool for individuals. BMI does not consider other variables that influence health risks, such as muscle and bone mass, lifestyle, sex or gender,ethnicity, race, and family history.
The American Medical Association (AMA) recommends against healthcare providers using BMI as a sole indicator of health and as a means to diagnosis obesity. Rather, the AMA argues, it should be used along with other measures, such as waist circumference, cholesterol tests, and other tools to gain a more comprehensive picture of an individual’s health and care needs.
This article will discuss the accuracy and inaccuracies of BMI, how to assess health beyond BMI values, and how to determine a healthy BMI for an individual.
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Use of Gendered LanguageOverwhelmingly, the data and research on BMI use binary gender measures of male and female, and does not account for gender diversity. This article uses binary gender language to reflect the current research, while recognizing that more research is needed that considers how BMI affects those who are not cisgender.
Use of Gendered Language
Overwhelmingly, the data and research on BMI use binary gender measures of male and female, and does not account for gender diversity. This article uses binary gender language to reflect the current research, while recognizing that more research is needed that considers how BMI affects those who are not cisgender.
BMI Accuracy: What Is True?
BMI is not a precise measure of body fat or health but can be used as a screening tool. It gives a measure that corresponds to weight categories (underweight, normal weight, overweight/pre-obesity,obesity classes 1, 2, and 3). BMI levels alone do not indicate a person’s health status, but BMI is moderately correlated with more direct measures of body fat.
Higher BMI levels are also correlated with elevatedmortality risk, and with an elevated risk for conditions such as cardiovascular disease, type 2 diabetes, and other health issues associated with overweight and obesity.
BMI is not an individual diagnostic tool, but it is useful for examining overall population trends and can be used as a starting point for determining an individual’s obesity-related health risks.
BMI RangesThe World Health Organization (WHO)categorizes BMI for adultsas:Underweight: Less than or equal to 18.5Normal weight: 18–24.9Overweight/pre-obesity: 25.0-29.9Class 1 obesity: 30.0–34.9Class 2 obesity: 35.0–39.9Class 3 obesity: Greater than or equal to 40These values are based on cisgender white men, and may need to be adjusted according to factors such as race and sex.BMI iscalculated differently for children and adolescentsthan it is for adults. Adult BMI measures and ranges cannot be used to assess BMI for people under 20 years old.
BMI Ranges
The World Health Organization (WHO)categorizes BMI for adultsas:Underweight: Less than or equal to 18.5Normal weight: 18–24.9Overweight/pre-obesity: 25.0-29.9Class 1 obesity: 30.0–34.9Class 2 obesity: 35.0–39.9Class 3 obesity: Greater than or equal to 40These values are based on cisgender white men, and may need to be adjusted according to factors such as race and sex.BMI iscalculated differently for children and adolescentsthan it is for adults. Adult BMI measures and ranges cannot be used to assess BMI for people under 20 years old.
The World Health Organization (WHO)categorizes BMI for adultsas:
These values are based on cisgender white men, and may need to be adjusted according to factors such as race and sex.
BMI iscalculated differently for children and adolescentsthan it is for adults. Adult BMI measures and ranges cannot be used to assess BMI for people under 20 years old.
BMI Inaccuracy: What’s Untrue?
BMI does not give a precise measure of body fat, and it cannot be used alone to determine an individual’s health. It is not a diagnostic tool; it just gives a general idea ofbody fat.
There are many factors that can affect BMI, but BMI is calculated using only height and weight. In addition, a BMI figure alone can have different implications depending on other contributing factors. Two people can have the same BMI, but have different levels of body fat and/or different health risks.
For example, at the same BMI:
Several studies have found that the current BMI ranges do not correlate accurately with some health risks, such astype 2 diabetes, for Asian Americans.
The WHO has noted that people of Asian descent can have a higher risk for some metabolic conditions at lower BMIs than the current classification ranges indicate.
BMI may be less accurate for certain ethnic groups, such as:
Available data also suggests that the association between BMI and body fat,dyslipidemia, metabolic syndrome, and all-cause mortality may be weaker for Black Americans than for White Americans. This may affect how BMI should be interpreted for this racial group.
More research is also needed on the accuracy of BMI with other racial and ethnic groups, such as people of Middle Eastern descent.
In addition, BMI does not take into consideration body makeup, such as the weight percentage due to fat, muscle, bone density, etc.
In general, BMI tends to be a less accurate tool for people such as:
How BMI is used can also be problematic. Because it is a simple, easy-to-use tool, there can be a tendency to use it as a sole indicator of health or to make health recommendations.
This may lead to important assessments being missed, such as dismissing heart health risks in someone whose BMI is in the normal range, or unnecessarily pressuring someone with aBMI above the normal rangebut without additional risk factors to lose weight.
Other potential downsides to BMI include:
Why Is My BMI High If I Am Not Overweight?BMI does not account for body makeup. A person with increased muscle mass and lower body fat may have a BMI that classifies them asoverweight or obese, but their body size may be smaller than someone with the same BMI who has a higher amount of body fat.
Why Is My BMI High If I Am Not Overweight?
BMI does not account for body makeup. A person with increased muscle mass and lower body fat may have a BMI that classifies them asoverweight or obese, but their body size may be smaller than someone with the same BMI who has a higher amount of body fat.
Assessing Health Beyond BMI Values
BMI is one of many tools that can be used to assess health related to body fat.
Waist circumferenceis another tool commonly used to assess potential health risks. Excessive abdominal fat is associated with an increased risk of conditions such as cardiovascular disease, type 2 diabetes, and high blood pressure (hypertension).
To measure your waist, do the following:
You may have a higher risk ofobesity-related health conditions if your waist circumference is more than:
As with BMI,waist circumferenceis another screening tool that can be used as part of a health assessment, but not as a sole indicator of health.Waist circumferencemeasurement is not appropriate for:
The AMA recommends additional measures fordiagnosing obesity, such as:
Tools healthcare providers may use include:
As part of a comprehensive health assessment, healthcare providers may also do other checks, such as:
BMI Chart for Women of All Ages
What Is a Healthy BMI for Me?
What a healthy BMI is for any individual depends on more factors than just which range the number falls in, including genetic factors, fitness levels, lean mass, health behaviors, environmental risks, and more. BMI alone should not be used as a health assessment but rather one screening tool among many.
Rather than rely on the one BMI reading, it’s best to see a healthcare provider for a comprehensive health assessment.
To calculate your BMI, visit the Centers For Disease Control and Prevention (CDC) website for the following calculators:
Summary
BMI is a popular tool used to categorize body mass based on height and weight. It is helpful as a screening tool when used alongside other measures of health, but it can be inaccurate or misleading when used on its own to assess an individual’s health risks.
BMI doesn’t take into consideration factors such as body composition,age, sex, race and ethnicity, genetics, and other variables that contribute to an individual’s health status and health risks. Instead of relyingsolely on BMI, see your healthcare provider for a comprehensive health assessment.
14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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