Why BMI May Not Be the Best Metric Menu Verywell Fit Nutrition Weight Management Nutrition Facts Nutrition Basics Diets Meal Plans Meal Delivery Services View All News Fitness and Nutrition What to Buy How We Test Products Fitness Gear Nutrition Products Tools Recipe Nutrition Calculator Weight Loss Calorie Goal BMI Calculator Body Fat Percentage Calculator Calories Burned by Activity Daily Calories Burned Pace Calculator About Us Editorial Process Meet Our Review Board Search Nutrition Basics Why BMI May Not Be the Best Metric By Rachel MacPherson, BA, CPT Rachel MacPherson, BA, CPT Rachel MacPherson is a health writer, certified personal trainer, and exercise nutrition coach based in Montreal. Learn about our editorial process Updated on July 30, 2021 Medically reviewed Verywell Fit articles are reviewed by board-certified physicians and nutrition and exercise healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Tyra Tennyson Francis, MD Medically reviewed by Tyra Tennyson Francis, MD Tyra Tennyson Francis, MD, is a board-certified family medicine physician and currently serves as the medical director of an outpatient clinic. Learn about our Medical Review Board Print Verywell / Alison Czinkota Table of Contents View All Table of Contents Defining BMI What BMI Can Reveal Limitations of BMI Further Problems with BMI How to Correctly Use BMI What to Focus on Instead There are multiple ways to measure health, and BMI or body mass index is one method used to categorize people based on their height and weight. This measurement is often utilized to determine individuals' diagnosis, treatment, and care but has come under scrutiny as a blanket approach lacking efficacy. BMI was developed by mathematician Adolphe Quetelet in the early 19th century, while he was studying crime in relation to social status. During his research, he discovered a link between height and weight. In the early 1970s, physiologist Ancel Keys began using the formula to determine obesity. Originally, BMI was specifically used for gathering large population samples of white men, but it has since been applied to individual men and women of all ages and races. BMI is still used today because it is an inexpensive and quick method for making assessments. According to the CDC, people with very high BMI are more likely to have high body fat percentages. However, relying on BMI creates issues with multiple population types, especially people of color. Defining BMI BMI measurements are obtained using a formula that finds the ratio of a person's height and weight. The formula uses a person's weight in kilograms divided by the square of their height in meters. This measurement is used for classifying people into specific categories of underweight, normal weight, overweight, or obese. These categories are used to determine the likelihood of particular potential health concerns or risks. BMI Measurement Weight Category Below 18.5 Underweight 18.5 – 24.9 Normal weight 25.0 – 29.9 Overweight 30.0 and above Obese You can use this calculator to determine your BMI: What BMI Can Reveal While BMI is only one factor of many used to point to potential health risks, it is most often correlated with the following conditions in overweight and obese populations: Coronary heart diseaseHypertensionOsteoarthritisSleep apnea and other respiratory conditionsCertain cancersStrokeType 2 diabetes For those with a BMI under the healthy or normal range, there are other significant potential health conditions: Cardiovascular diseaseDepressionDifficulty getting pregnantDry skinHair lossIrregular menstrual cyclesNutrient deficienciesOsteoporosisReduced immune system function Limitations of BMI For some groups of people, it's best not to rely on BMI since it cannot provide an accurate picture of health even more significantly than the average person. These people include: Muscular individuals or those who are very athletic Pregnant and lactating individuals The elderly Children Using the body mass index leaves out crucial information that can help determine a person's health status. For example, only using a person's height and weight leaves out the amount of body fat, bone, and muscle mass they might have. Muscle is much more dense than fat, and therefore, individuals with a high amount of muscle mass may be heavier even with less dangerous body fat levels. Many athletic people with a higher than average muscle mass will find themselves in the overweight range of BMI. Conversely, elderly individuals may have less muscle mass than the average, and children have not yet fully developed their bones and muscles. Why Getting Older Causes Your Body Shape to Change Further Problems with BMI BMI also does not consider lifestyle habits such as diet and exercise, stress levels, or other factors such as genetics, environment, or race. Moreover, when BMI determines diagnosis and care outcomes, more issues can arise. Some people have been denied access to care for issues such as eating disorders and fertility treatments. Insurance companies often still rely on BMI when determining coverage and rates, resulting in unfair outcomes. BMI was never designed to track individual health and, in particular, lacks effectiveness for women and people of color. Some ethnic groups have higher health risks than others, and relying on BMI to predict these health risks can leave some people out of receiving the care they may need. For example, Asians have been shown to have more than twice the risk of developing Type 2 diabetes than Caucasians at the same BMI. Hispanics and black people have a greater risk of diabetes than white people at the same BMI. Since BMI was developed using the data of white males, some people may be neglected when they should be receiving care. Researchers have shown that a BMI of 30 or over is linked to a higher risk of Type 2 diabetes for white people, but for black people, 28 is a more accurate cutoff while the cutoff is 23.9 for South Asian populations and 26 for Middle Eastern people. This discrepancy could leave many at-risk individuals without proper care at critical times. People who may file into the overweight or obese range yet are active and have healthy blood pressure, and cholesterol levels may be told they need to lose weight when they don't need to. This false determination may lead to self-image and body shaming issues and lacks a complete picture of the person's actual health status. Body Shape Drives Fat Stigma Even More Than Weight How to Correctly Use BMI BMI should be part of a bigger picture when considering a person's health. Considering BMI can potentially indicate a starting place for working on improving health outcomes but should be part of a broader range of measures such as: The ratio of body fat to lean mass Waist circumference Neck circumference Waist-to-hip ratio Blood sugar levels Cholesterol levels Stress levels Sleep habits Blood pressure Family medical history Diet Physical activity levels Habits like drinking and smoking If you are concerned about your BMI, speak with a health care provider while also discussing your overall health habits. Health care providers can use BMI as a jumping-off point for diving deeper into a person's health factors. If someone has a high BMI, it could be wise to order further lab tests, particularly if they belong to a more at-risk population for medical conditions such as Type 2 diabetes. Your care provider can then determine ways to reduce your risks of these conditions, if necessary, such as diet and exercise changes. What to Focus on Instead Those who would like to track their body measurements would be better served using formulas and tools to provide a clearer picture of body composition. Body composition is the amount of lean mass, including muscle, bone, and organs, compared to fat mass. Tracking body composition is especially helpful for those who are athletic or fit and tend to have a more significant muscle mass ratio than the general population. There are various methods of tracking body competition, including bioelectrical impedance, skinfold measurements, and underwater weighing. Another indicator that is more reliable than BMI regarding potential health concerns is the waist-to-hip ratio (WHR). This measurement compares your waist size to the size of your hips in inches and is often used to determine the risk of heart disease a person may have. To obtain your WHR, simply divide your waist measurement by your hip measurement in inches. A waist-to-hip ratio greater than 1.0 indicates a higher than average risk of developing heart disease. A healthy WHR is less than 0.85 for women and 0.90 or less for men. How to Measure Your Waist-to-Hip Ratio A Word From Verywell While BMI may help health care providers determine whether more tests should be performed, it is not an adequate stand-alone indicator of health. Many other factors determine your health status, including your lifestyle habits, body composition, ethnicity, and genetics. If you are concerned about your BMI or your health in general, speak to your doctor. If you are at risk of health conditions, your doctor can help you develop a plan to improve your outcomes, such as diet and lifestyle changes. 8 Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Centers for Disease Control. About Adult BMI. National Institute of Diabetes and Digestive and Kidney Diseases. Health risks of overweight and obesity. Komaroff M. For Researchers on Obesity: Historical Review of Extra Body Weight Definitions. J Obes. 2016;2016:2460285. doi:10.1155/2016/2460285 Harvard Health. Ethnic Differences in BMI and Disease Risk. Caleyachetty R, Barber TM, Mohammed NI, et al. Ethnicity-specific BMI cutoffs for obesity based on type 2 diabetes risk in England: a population-based cohort study. The Lancet Diabetes & Endocrinology. 2021;9(7):419-426. doi:10.1016/s2213-8587(21)00088-7 Hamer M, O'donovan G, Stensel D, Stamatakis E. Normal-Weight Central Obesity and Risk for Mortality. Ann Intern Med. 2017;166(12):917-918. doi:10.7326/L17-0022 Cao Q, Yu S, Xiong W, et al. Waist-hip ratio as a predictor of myocardial infarction risk: A systematic review and meta-analysis. Medicine (Baltimore). 2018;97(30):e11639. doi:10.1097/MD.0000000000011639 World Health Organization. Waist circumference and waist-hip ratio: report of a WHO expert consultation. By Rachel MacPherson, BA, CPT Rachel MacPherson is a health writer, certified personal trainer, and exercise nutrition coach based in Montreal. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit Related Articles Ideal Weight Calculator: Weight, Height, and BMI Charts What is the Average Weight for Women? How to Measure Your Waist-to-Hip Ratio BMI and Kids: Should You Care? What Is the Average Weight for Men? Calculate Your Body Mass Index (BMI) With Our Calculator What Waist Circumference Can Tell You About Your Health The Drawbacks of Using BMI to Measure Health What Does It Mean to Be Underweight? How to Use Quick Body Measurements to Calculate Body Fat Percentage Is It Safe To Lose Weight While Pregnant? What Is Health at Every Size and Why Is It Important? What Is Yo-Yo Dieting? How to Stop the Cycle How Much Weight Is Safe to Lose in 1 Week? Body Composition: What You Need to Know What Is the Average Height for Men? When you visit the site, Dotdash Meredith and its partners may store or retrieve information on your browser, mostly in the form of cookies. Cookies collect information about your preferences and your devices and are used to make the site work as you expect it to, to understand how you interact with the site, and to show advertisements that are targeted to your interests. You can find out more about our use, change your default settings, and withdraw your consent at any time with effect for the future by visiting Cookies Settings, which can also be found in the footer of the site. Cookies Settings Reject All Accept All