Did you know that according to the World Health Organization, about one in 8 people are suffering from obesity globally? Obesity is a serious, chronic condition with far-reaching health consequences. In 2022, 2.5 billion people were overweight and among them 890 million were obese. In 2021, high body mass index (BMI) directly caused 1.6 million premature deaths from non-communicable diseases (NCDs). By 2030, more than 2.9 billion adults are expected to have a high BMI, including 1.1 billion living with obesity (BMI of 30 or higher). Notably, nearly 400 million adults will fall into obesity class II (BMI of 35 or higher), with women making up majority of this group. As excess weight becomes more common worldwide, it’s clear that it has become a public health crisis.
India is also facing an exponential rise in obesity with National Family Health Survey (NFHS-5) revealing that nearly one in four Indian adults aged 15-49 is overweight or obese. These numbers have increased steadily over the past two decades, driven by urbanisation, sedentary work, processed diets, and socio-economic shifts. Hence, tackling obesity means confronting these root causes head-on, not just managing its effects. Understanding the epidemiology of obesity is key to turning the tide.


Epidemiology of obesity
Epidemiology, the study of disease patterns in populations, is pivotal in understanding dynamics of weight. It studies behaviours, environments, and biological changes to understand broader health trends. When applied to weight loss, epidemiology helps distinguish between beneficial, intentional changes and those that reflect deeper, systemic issues. It helps in identifying risk factors like diet, activity, and genetics; tracking weight trends to reveal broader influences; evaluating the success of weight management strategies; shaping targeted public health interventions; and assessing how weight changes impact overall health.
Key areas of this epidemiological research span several interconnected fields. Obesity epidemiology focuses on understanding how widespread obesity is, how it is distributed across populations, and the various risk factors that contribute to it. Understanding the epidemiology of obesity is important as it is a gateway to multiple life-threatening conditions. These include type 2 diabetes, heart disease, stroke, osteoarthritis, chronic back pain, sleep apnea, and several types of cancer such as breast, colon, and pancreatic. It impairs insulin function, strains the cardiovascular system, damages joints, and disrupts normal breathing during sleep. Far beyond excess weight, obesity acts as a catalyst for a cascade of life-threatening illnesses that affect nearly every organ system.

The 'skinny-fat' phenomenon
A unique concern in India is the 'thin-fat' phenotype, where individuals appear lean but have high body fat percentages and low muscle mass. This condition increases susceptibility to metabolic disorders like type 2 diabetes and cardiovascular diseases. Abdominal obesity affects 40% of women and 12% of men in India. Among women aged 30 to 49, the data shows that 5 to 6 out of every 10 women fall into this high-risk category. Therefore, in India, waist circumference is considered a more accurate indicator of health risks compared to BMI alone. The waist circumference-to-height ratio is also commonly used to assess abdominal obesity.
The numbers are staggering, and the trajectory is rising. Obesity is preventable and, in many cases, reversible. Moreover, losing excess weight can have multitudes of benefits as even a modest reduction (5-10%) in body weight can lead to measurable improvements in blood pressure and cholesterol levels. Therefore, greater weight loss will lead to greater health benefits.
In countries like India, where obesity is rising in tandem with economic growth, the challenge is to balance development with health. This involves coordinated action across sectors such as healthcare, education, agriculture, and urban planning. To change the future, we must start by recognising obesity not as a failure of willpower but as a complex, chronic disease that demands serious action.


Authored by: Dr Nitin Kapoor