Body Mass Index (BMI) of 18
You are in the Underweight category.
Where do you stand on the BMI chart:
Celebrities with similar BMI
What is Body Mass Index (BMI)?
Body Mass Index (BMI) is an indicator calculated based on your gender, height, weight, and frame size. It tries to
estimate the amount of fat on your body. Based on the calculated value, you can be classified as underweight, normal, slight
overweight, overweight, or extremely overweight. It is important to know where you are standing in this scale as too
much or too little fat on the body can potentially cause health related issues (e.g., coronary heart disease, sleep apnea, and
type 2 diabetes). Therefore, being at either extreme of the BMI spectrum (i.e., being underweight or extremely overweight) is
not healthy. Generally speaking, BMI is calculated as shown above. In metric system, simply divide your weight by your height
and then divide the resulting number by your height again. Thus, height plays an important role in your BMI result. This is
expected as the taller you are, the more mass you can naturally have on your body.
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Distribution of BMI in the population
As you know, not everybody has the same BMI. Here, you can see two distributions (blue and red). The blue one was
gathered from year 1976 to 1980 and the red one was gathered from year 2005 to 2006. Based on the red curve and your
weight category, your BMI is lower than about 93 percent of the population while it is
higher than about 4 percent. These statistics were gathered by the National Health and
Nutrition Examination Survey (NHANES). Comparing the red and the blue curves, as you can see, over the last few decades,
the distribution of BMI values has been shifting to the right side. This simply means that nowadays, a larger faction
of the population falls in the overweight category. There is a host of issues contributing to this trend such as easier
access to food, less overall activity, higher calorie meals, prevalence of office type jobs, higher stress level, and
Why is BMI important?
Although BMI is a simple indicator, many scientific studies have shown that, statistically speaking, a healthy BMI translates
to a longer and healthier life. A high BMI value increases your chance of developing type 2 diabetes and cardiovascular and
gallbladder diseases. At the other end of the spectrum, a low BMI value can significantly increase your chance of digestive
and pulmonary diseases. Given these risk factors, the plot above shows the in-hospital risk of death for different BMI values
normalized to the best range (i.e., values between 20 to 25). For example, patients with BMI of 40 have 2X higher risk
compared to those with BMI of 22.