Doc Talk: Why A Normal BMI Doesn't Always Mean Good Metabolic Health

A normal reading on the weighing scale does not necessarily mean a healthy metabolism. For Indians, the distribution of body fat may be as important as total body weight. For years, weight management has been reduced to a deceptively simple equation: maintain a healthy body weight and the risk of lifestyle diseases will remain low.

This assumption is increasingly difficult to defend. A person can fit comfortably into old clothes, have a body mass index (BMI) within the normal range, and still carry excess fat around the abdomen that warrants medical attention.

The problem is not with bulging or collecting fat in your belly, but abdominal fat is highly important only if it is visceral fat that is deep fat. Velcro means fat that is deep inside the stomach around the internal organs.

Unlike the fat lying just under the skin, visceral fat is active in metabolism and leads to insulin resistance, elevated cholesterol, and inflammation that raises the chances of developing type 2 diabetes and cardiovascular disease.

For India, this deserves particular attention. The nationally representative ICMR-INDIAB-23 study, published in 2025, reported that 43.3% of the population had metabolic obesity despite a BMI below 25 kg/m². This finding challenges the assumption that a normal BMI is sufficient evidence of metabolic health.

It also strengthens the case for looking beyond body weight when assessing an individual's risk. BMI measures weight in relation to height. It does not distinguish between muscle and fat, identify where fat is stored or directly measure insulin sensitivity.

Two people with identical BMIs can therefore have substantially different body compositions and metabolic risk profiles. This distinction is particularly relevant to Indians, who may develop metabolic abnormalities at lower levels of BMI than some other populations.

A sedentary lifestyle, limited muscle mass, prolonged sitting, and a diet high in refined carbohydrates and energy-dense foods can contribute to a pattern in which a person appears relatively lean but carries excess abdominal fat.

Contemporary professional routines may worsen the situation. Working at a desk for too long, eating in-between meetings, having meals delivered frequently, spending late hours in front of screens, and poor sleeping behavior make it difficult to stay active and keep the weight.

It is not that any of these habits lead to abdominal obesity. They can collectively contribute to body changes and changes in metabolic processes without changing weight significantly. Genetic traits, age, hormone-related issues, some medications, and existing health problems can also play a role in body fat distribution.

ALSO READ | Doc Talk | How Diwali Air Pollution Affects Your Eyes And Puts Your Vision At Risk It is necessary to differentiate visceral fat from subcutaneous fat found under the skin and can be held with the fingers. The body shape of an individual can sometimes give clues to posture, abdominal bloating, gastrointestinal problems, or more serious ailments.

However, one's appearance cannot be enough to assess the amount of visceral fat present in the body or the presence of metabolic disease. A better way to start is the waist measurement. The waist-to-height ratio is a straightforward method of evaluating central obesity along with BMI, and it takes the waist measurement and height using the same measurement units for both.

For instance, the waist-to-height ratio of an individual standing at a height of 160 centimeters with a waist measurement of 84 centimeters is equal to 0.525. The resulting value is within the range of values implying excessive abdominal fat according to conventional medical sources.

In general, the ratio should ideally be less than 0.50. The ranges between the ratios of 0.50 and 0.59 indicate the presence of excessive abdominal fat, and a ratio greater than 0.60 requires more serious concern. Such limits do not serve as a conclusive diagnosis but as indicators that help to assess the level of risk associated with a person's ratio.

The next step is to analyze what the ratio might mean clinically. In accordance with the person's age, medical background, and other risk factors, the doctor could request certain tests to assess their blood pressure, blood glucose level, and fat content level.

In some situations, a doctor could suggest conducting assessments that are suitable for the specific case of a patient. ALSO READ | Doc Talk | Smartwatch Heart Rate Alerts: When Should You Worry And Consult A Doctor? One of the least helpful responses to abdominal fat in a person with a normal BMI is to recommend indiscriminate weight loss.

Restrictive dieting can reduce muscle mass, leave nutritional needs unmet, and make the person lighter without necessarily improving body composition. The more appropriate objective is to reduce excess abdominal fat, preserve or build muscle and improve metabolic markers.

That requires a shift from weight-centred thinking to health-centred behaviour. Start with strength training two times in a week. Walking and other aerobic physical activities will help to improve the cardiovascular system; however, resistance exercises are also vital for the sustainment of muscle mass and insulin sensitivity.

People who are 18 and older must do muscle strengthening exercises involving the largest muscle groups not less than twice a week and along with aerobic exercises. According to the World Health Organization, individuals need to engage in moderate aerobic activity between 150 and 300 minutes a week or a similar amount of vigorous activity.

However, if you are not used to exercising, it would be wise to embark on your exercise plan little by little, as it is advisable to refrain from training too hard. Secondly, instead of cutting food groups out of your diet, consider changing your dishes.

Indian cuisine can prove to be quite effective for maintaining an efficient metabolism if it includes a sufficient amount of...