A paper published in the scientific journal Obesity offers an equation that calculates that percentage using only centimeters. Although the obesity epidemic has turned the scale into a widespread item like a toothbrush, doctors agree that what really matters is not weight, but the amount of fat tissue in the body. The problem is that the methods available for measurement until now have not been very precise or as easy to inspect as weights on a scale.
However, a paper published in the scientific journal Obesity offers a solution: an equation that calculates body fat percentage using just centimeters. What’s more: experts from the Argentine Society of Obesity and Eating Disorders (Saota) have turned that formula into an automatic calculator that anyone can access on their website: www.saota.org.ar.
In 1835, the Belgian astronomer, mathematician and naturalist, recognized as one of the fathers of modern statistics, Lambert Adolphe Jacques Quételet, set forth his theory of the “average man”: in Sur l’homme et le développement de ses facultés, essai d’une physique sociale (On man and the development of his abilities, an essay on social physics) is a simple calculation for classifying the ideal weight with respect to height.
This index, called “Quételet” at the time and derived from dividing weight by height squared, is nothing less than the well-known body mass index (BMI), which is widely used today to decide whether a person is within their weight range (when the result is between 18 and 24.9), overweight (between 25 and 29.9) or obese (more than 30).
But although BMI has been used for more than a century and a half, it is known that it does not differentiate between lean tissue and body fat. For example, densitometry studies carried out in Argentina by Dr. Carlos Mautalén and his team from the Medical Osteopathies Center compared first league soccer players with a group of young men of the same BMI and found that while the former had 9 kilograms of fat, the latter had 16.
To “sharpen the target”, in their work on obesity, Richard Bergman and colleagues proposed an alternative parameter: body adiposity index (BAI).
“It is a calculation that allows the estimation of total body fat,” explains Dr. Julio Montero, board member of the Argentine Society of Obesity and Eating Disorders (Saota). The significant thing is that it can be applied up to half the field with an instrument no larger than a centimeter and possibly a computer or calculator.”
A revealing equation
To create their index, which has been validated for adults of both sexes but not for children, Bergman and her co-authors drew on a study that collected various body measurements from a population of 1,733 health insurance patients of Mexican origin. Kaiser Permanente of Southern California, in Los Angeles County.
Scientists have tried to identify a combination of traits that could be associated with obesity. They then validated the index results with those obtained by densitometry.
After adjusting the variables, they got a formula that shows the total percentage of adipose tissue. Those who visit the Saoto website will be able to calculate this automatically thanks to the contribution of Martín Milmaniene, secretary, and Rosa Labanco, director of the entity’s Center for Teaching, Assistance and Research.
It is enough to enter the circumference of the hips taken in centimeters on the part of the buttocks that stands out the most, and the height in meters,” explains Montero. “The percentage of fat that your body has appears immediately. If it exceeds 35% in “women or 25% in men, it indicates excess fat and a possible increased cardiovascular risk. Until now, it could not be known unless you had densitometry, with the costs and logical complications that it requires. “
Although the work, which was funded by the United States Institutes of Health, was conducted on people of Mexican descent, its authors confirm that there is evidence that it should be extrapolated to the white population and anticipate conducting additional research to generalize it.
According to Bergman and colleagues, the work was based on the assumption that the percentage of obesity in itself is a physiological characteristic of overweight and obese individuals that exposes them to the risk of cardiovascular disease.
“The relationship between fat percentage and cardiovascular risk is well documented. However, there is compelling evidence that visceral or liver fat may be a better predictor than global percentage (…) and it might be interesting to compare BAI with selected fat depots in the future,” they write scientists.
For Montero, the new index will complement other measurements, such as the now classic BMI or direct observation of the distribution of fat tissue, and thus enable expansion and more precise professional evaluation.
“Fat accumulation in the tail is not the same as in the abdomen,” Montero says, “but having an estimate of the amount is a very good first approximation for risk taking.”
Contrary to what is often believed, adipose tissue is not inert: today we know that it is not just a “closet” for fat storage, but secretes hormones and affects numerous body systems.
Namely, it is an endocrine organ, but unlike other glands, its mass is variable, and its action varies according to the position and volume of adipocytes.
“Excess body fat is harmful to health – emphasizes Dr. Gustavo Lobato, nutritionist, sports medicine specialist and vice president of Saoto -. When fat is “excessive”, adipocytes “suffocate”.
According to Lobat, when the adipocytes of the subcutaneous cellular tissue become excessively filled, they cease to fulfill their function as reservoirs, swell like balloons and, in doing so, move away from the capillaries, the tiny blood vessels that supply them with oxygen. “It could be said that in this situation adipocytes become inflamed and start to “cry” – illustrates the expert – they secrete fatty acids and “adipokines”, substances that transmit inflammation from adipose tissue to the whole body. In the walls of the arteries, they predispose to arteriosclerosis and high blood pressure , and in the muscles they prevent the re-intake of glucose, the circulation of which increases in the bloodstream after the intake of carbohydrates… This hyperglycemia, if maintained over time, leads to type II diabetes.”
Adipokines also act on the hypothalamus to produce the release of cortisol, which in turn redistributes fat and increases its deposition in the abdomen. “That is, when you see a person with a prominent belly, you already know that their body is going through an inflammatory process,” says Lobato.