Obesity, the scourge of our times, leads to an increased risk of cardiovascular diseases such as heart attacks and strokes, and cardio-metabolic diseases like diabetes and high cholesterol levels. Body Mass Index (BMI) can be considered as a conventional metric for identifying obesity. One is considered obese if one has a BMI of over 30 . However, BMI fails to distinguish between fat-free mass i.e. muscle, and adipose (fatty) tissue.
Furthermore, BMI is unable to accurately depict the distribution and extent of potentially dangerous internal fat deposits. Hence, contrary to popular perception, people with normal BMI may also exhibit high levels of body fat, a condition termed as the thin-fat paradox or normal weight obesity, By Dr. Joy Shome, Consultant Intervention Cardiologist, B M Birla Hospital told Financial Express.com.
“The hallmark of the thin-fat paradox is the presence of potentially dangerous excess internal fat deposits. These fats stored deep inside the body are the visceral fats, a lot of which can lead to significant cardiovascular risks despite the absence of traditional obesity indicators. Commonly, fat in the body is stored underneath the skin, termed as subcutaneous fat, and this is visible, and can be felt. Visceral fat on the other hand, is stored deep in the abdomen and around the internal organs like the stomach, liver, intestines, and kidneys. Excess visceral fat is characterised by the presence of a “pot belly”, or central obesity in scientific parlance,” Dr. Shome said.
He also maintained that high levels of visceral fat are harmful to the body in that these produce toxic substances and adversely alter the metabolic balance of the body leading to high cholesterol and insulin levels, and clogging of arteries. One often hears of the term “metabolic syndrome” that has been used in relation to this entity.
How visceral fat affects the heart?
Visceral fat can also be found around the heart. “Atrial fibrillation is a widely prevalent heart rhythm abnormality characterised by an irregular heart rhythm. This can lead to the formation of blood clots in the heart which in turn can migrate to other organs such as the brain causing a brain attack or stroke. It can also reduce the pumping function of the heart,” Dr. Shome told Financial Express.com.
While high BMI can be considered a risk factor for atrial fibrillation, it is now increasingly recognised that visceral fat surrounding the heart can be more harmful as toxic substances released by visceral fat can play a significant part in the development of atrial fibrillation, he said.
Normal weight obesity can pose similar or even more severe health risks compared to traditional obesity, leading to metabolic syndrome and cardiovascular diseases.
“It is usually the result of a complex interplay between genetic or inherited factors, and lifestyle related issues. Consumption of a diet high in calories particularly from processed foods and sugary beverages, and a stark lack of exercise contribute significantly towards the accumulation of increased internal body fat even if the overall body weight remains normal. Normal weight obesity can be caused by genetic and hormonal factors – certain genetic predispositions may lead to individuals gaining fat more easily,” he explained.
Additionally, particular hormonal imbalances can contribute to abnormal fat accumulation despite normal weight. Research indicates that this obesity paradox affects up to one-third of individuals in certain South Asian populations, such as Indian and Chinese. Consequently, the World Health Organisation recommends a lower BMI cut-off to identify people at risk in South Asia, primarily because individuals in the region tend to have a higher body fat percentage at lower BMI as compared to other ethnic groups.
How to lower serious health risk?
Mitigating the serious health risks associated with the thin-fat paradox requires early identification of normal weight obesity and implementing preventive measures and lifestyle interventions to counter it.
“In most cases, normal weight obesity can stay unidentified till it reaches serious stages resulting in diabetes and debilitating cardiovascular conditions like heart attacks and brain strokes. Indians are sustaining life threatening heart attacks at a very young age in comparison to their Western counterparts. Altered body fat distribution may cause inflammation, oxidative stress, increased risk of cardiovascular disease and diabetes, and alterations in muscle mass and strength,” Dr. Shome said.
Management of normal weight obesity requires a multi-pronged, holistic approach – early identification and diagnosis of the altered metabolic milieu in the body (eg. abnormal blood sugar and cholesterol levels) and its appropriate treatment, in conjunction with a strong emphasis on lifestyle modifications including healthy dietary patterns and regular physical activity.
“This is a pivotal time for our country. Whether a care-giver or recipient, as India looks to become a 10 trillion dollar economy and wishes to maximize its demographic dividend, a societal responsibility of increased health awareness and adoption of active preventative measures, befalls on each one of us,” he said.