'189cm·72.2kg' Cha Seung-won is Normal, 'Muscle Mass 44%' Yoo Jae-tae Says "Obese" [Curiosity Lab]

Actor Cha Seung-won is tall at 189cm but maintains a weight of 72.2kg. Recently appearing on tvN’s “You Quiz on the Block,” he said he maintains his weight by eating only one meal a day. This is his lowest weight since he was twenty. He stated, "Self-management is a kind of measure of diligence," and added, "I think managing myself is the minimum courtesy to those who watch me." Cha Seung-won's Body Mass Index (BMI) is 20.15, which is normal. BMI is calculated by dividing one’s weight (kg) by the square of their height (m). A BMI of 18.5 to 22.9 is considered standard weight, 23 to 24.9 is overweight, 25 to 29.9 is mild obesity, and 30 or above is moderate obesity. If Cha Seung-won were to gain more than 10kg and reach 83kg, his BMI would be "23.23, which is overweight," and at 90kg, "it would be over 25, which is obese." Actor Yoo Ji-tae, who is 188cm tall, gained weight up to 100kg last year for a role; although his BMI would classify him as obese, he was called a bulked-up physical powerhouse with muscle mass increased to 44%.

The average height and weight of Koreans (based on 2021 data from the National Institute of Technology and Standards) are 172.5cm and 74kg for men, and 159.6cm and 59kg for women. Men fall into the obese category (BMI 25), and women are overweight (BMI 23). The obesity rate was 47.0% for men and 22.6% for women.

The scene of the MyDietFair held in 2022 [Photo by MyDietFair]

Although BMI is not an absolute measure, it is an important standard and a source of stress for those battling weight. Judging obesity solely based on height and weight is actually outdated. Even if someone and others say they have a "proper figure," if BMI consistently labels them as "overweight" or "obese," it can be discouraging. In reality, BMI does not show anything about body composition such as muscle or fat mass. Some people have a high BMI but low body fat. Muscular soccer players or bodybuilders often have high BMIs but actually low body fat. Conversely, people with very little activity may have a normal BMI but high body fat and an unflattering figure. According to the Japanese standard for "weight that looks good in clothes," the criteria are stricter than BMI. For men, 175cm and 62.7kg, and for women, 161cm and 48kg are considered to look good in clothes. Both have normal BMIs but are about 10kg lighter than the average Korean weight.

More important than BMI is actually waist circumference. According to data from the National Health Insurance Service (2021), the average waist circumference is 86.0cm (33.9 inches) for men and 76.6cm (30.1 inches) for women. Abdominal obesity is diagnosed when waist circumference is 90cm (35.4 inches) or more for men and 85cm (33.5 inches) or more for women. The rate of abdominal obesity is about 3 in 10 men and 3 in 10 women. The country with the highest obesity rate in the world (percentage of adult men with BMI 30 or above) is American Samoa in the South Pacific, where 70% of adult men are obese. Most of the top-ranking countries are island nations, with the United States ranking 10th at 41.64%. South Korea ranks 151st at 8.82%. The three Northeast Asian countries?China (8.94%, 149th), Japan (7.63%, 161st), and South Korea?are all pleasantly low in the rankings.

Other methods to classify obesity include waist circumference measurement, waist-to-hip ratio, and the Edmonton Obesity Staging System (EOSS). Waist circumference (WC) is an inexpensive and easy measurement method. The waist-to-hip ratio (WHR) is the waist circumference divided by hip circumference; a ratio of 0.85 or higher for women and 0.9 or higher for men indicates abdominal obesity. Men with a waist-to-height ratio of 1.0 or higher and women with a weight-to-height ratio of 0.85 or higher are considered at high risk. Most people obsess over the belief that a thin body is a healthy body, but recent studies suggest this is not necessarily true. Some people in the overweight BMI category have a lower risk of death from heart-related causes than those with a normal BMI. This is because BMI can misrepresent an individual's health status when compared to objective indicators like cholesterol or blood sugar test results. Drawing conclusions about a person's health using weight-based tools like BMI can add confusion.

The world is waging a war against obesity. According to the international medical journal The Lancet, in 2022, the global obese population was 1.038 billion, based on a BMI of 30 or above. Adults accounted for 879 million, and children and adolescents 159 million. Women numbered 540 million, and men 374 million, with women 35% more than men. Regionally, the most notable increases in obesity were in Polynesia and Micronesia in the South Pacific, the Caribbean, the Middle East, and North African countries. In South Pacific countries like Tonga, Samoa, and Nauru, 6 out of 10 adults are severely obese. Countries like South Korea, China, Japan, and Vietnam had lower rates.

According to another statistic from World Atlas, 70% of adults in Tonga are obese. Following Tonga, the countries with the highest obesity rates are island nations such as Nauru, Tuvalu, Samoa, and Kiribati. Samoa’s obesity rate once reached 70% but has decreased to 61%. The high obesity rates in island nations are due to the sudden import of processed foods after World War II.

Hawaiians, who have a less sedentary lifestyle compared to other states, have a lower obesity rate.

Fast food is inexpensive but high in calories, making it a major cause of obesity in the United States. The obesity rate in the U.S. has risen to epidemic levels. Twenty years ago, no state had an obesity rate over 15%, but now more than 22 states have rates exceeding 30%. Mississippi, West Virginia, and Arkansas have rates over 34%. Colorado (21.30%), Hawaii (22.10%), Massachusetts (23.30%), and California (24.70%) are among the states with lower rates. Differences in obesity rates by state are due to various factors such as income, education, healthcare, and geographic environment. Colorado and Hawaii, with obesity rates around 21%, generally have lifestyles involving less sitting. People in these states also tend to be the leanest. These states enjoy biking and have many hiking trails. One reason for higher obesity rates in southern states, where more adults lack a high school diploma, is the concentration of less-educated adults. According to a report by the U.S. Centers for Disease Control and Prevention (CDC), over 33% of adults without a high school diploma are obese.

Simple math formulas or scale numbers cannot measure a person’s health. Using scales for that purpose can actually cause harm. Labeling a person’s weight and BMI as "not normal" can hinder them from receiving necessary treatment. Instead of asking "What is a healthy BMI?" it is better to invest time and energy in scientifically proven strategies known to promote health.