Cardiovascular diseases and strokes are among the leading causes of disability and death in adults. Among these, obesity is a significant contributing factor. Overweight and obesity are considered diseases of the 21st century, with rising prevalence rates and a trend toward younger age groups.
According to the WHO, overweight is defined as a weight that exceeds the appropriate threshold for one’s current height. Obesity refers to an abnormal and excessive accumulation of fat in a specific area of the body or throughout the body, leading to various health risks such as cardiovascular disease, dyslipidemia, diabetes, and musculoskeletal disorders. The BMI (Body Mass Index) has long been used to assess overweight and obesity. A BMI of 25 – 29.9 is considered overweight, and a BMI greater than 30 is classified as obesity.
However, an interesting finding reported by Japanese researchers on ResearchGate reveals that Japanese Sumo wrestlers, typically weighing between 130 – 180 kg with a waist circumference and a BMI of 35.5-36.5, significantly higher than the average person, do not suffer from obesity-related conditions such as hypertension, diabetes, or strokes. They appear remarkably strong, agile, and flexible on the wrestling mat.
Sumo is a traditional sport in Japan, regarded as a symbol of strength among its people. Japanese researchers revealed that CT scans of Sumo wrestlers show very little visceral fat and primarily subcutaneous fat. Blood tests also indicate low levels of blood sugar, cholesterol, and triglycerides, helping them avoid the complications associated with obesity, thus being considered healthy obese individuals.
Why is this phenomenon observed? The answer lies in the distribution of fat in their bodies and their dietary and training regimens.
Sumo is a traditional sport in Japan, regarded as a symbol of strength among its people. (Illustrative image).
Reasons Why Sumo Wrestlers Are Called “Healthy Obese”
Generally, body fat is distributed in two forms.
1. Subcutaneous Fat
Subcutaneous fat is the most common type, located just beneath the skin, concentrated around the buttocks, hips, and thighs. This layer of fat can be observed visually or measured with skinfold calipers. It is generally considered relatively safe and non-harmful.
2. Visceral Fat
Visceral fat lies deep within the body’s cavities, surrounding organs such as the heart, liver, intestines, and pancreas. It can only be identified through CT scans or MRIs, which are often expensive, time-consuming, and typically accompanied by waist circumference measurements for predictions. Numerous studies indicate that this visceral fat layer is the primary cause of dangerous health issues.
Visceral fat increases insulin resistance—a hormone secreted by the pancreas that lowers blood sugar levels. Consequently, individuals with obesity are often at higher risk for diabetes, increased inflammatory responses, arterial stiffness, and damage to the cardiovascular system and other organs.
Even if you have a normal BMI and weight, this fat can accumulate in your body and lead to complications. When subcutaneous fat levels become too high, there is a tendency for it to convert into visceral fat.
Additionally, we need to pay attention to the waist circumference, which is the circumference of the narrowest part of the abdomen, located between the lower edge of the last rib and the top of the hip bones, above the navel. A waist circumference greater than 90 cm for men and greater than 80 cm for women in Asian populations has been shown to increase the risk of cardiovascular disease and diabetes.
The waist-to-hip ratio (WHR) is the ratio of the waist circumference to the hip circumference and is a method by which doctors can assess whether excess weight poses a health risk. According to WHO guidelines, an WHR of 1.0 in men increases the risk of cardiovascular disease and other conditions related to overweight.
BMI is a tool based on the relationship between weight and height to assess whether an individual is overweight, without considering the distribution of fat in the body. Therefore, doctors find it challenging to predict the risk of disease in patients solely based on BMI. WHO has also included waist circumference and the waist-to-hip ratio (WHR) as useful tools for predicting the likelihood of cardiovascular disease. Many people confuse waist measurement with belly measurement.
Men tend to accumulate fat around the waist, while women typically store fat around the hips and thighs.
Sumo wrestlers follow strict training and dietary regimens. (Illustrative image)
Returning to Japanese Sumo wrestlers, their condition is due to high training intensity, typically starting at 5 a.m., lasting continuously for 5 hours, combined with a strict diet. This high-intensity training helps their bodies release adiponectin, a hormone secreted by fat tissues that enhances insulin sensitivity, stabilizes blood sugar levels, reduces the risk of diabetes, and promotes fat distribution in subcutaneous form, reducing the volume of visceral fat. However, when they cease competition, subcutaneous fat may convert to visceral fat, which can harm their bodies.
Therefore, to effectively reduce visceral fat, a combination of diet and exercise is essential. To assess overall health, in addition to BMI, waist circumference and waist-to-hip ratio also contribute to more accurate evaluations of the risk of cardiovascular disease and related conditions.
