What is obesity and how it is calculated?

Diets based on an excess of nutrients, fats, and fast food and an increasingly sedentary way of life are the breeding ground for obesity to become a true epidemic. Learn to control your weight.

Obesity is the most common metabolic disorder in human clinical practice, which could be defined as an excessive accumulation of fat due to an energy imbalance between calories consumed and expended. It can lead to serious health problems ( diabetes, cardiovascular diseases, musculoskeletal problems, and even various cancers ).

In industrialized countries, current living conditions allow an abundant and varied diet forever larger sectors of the population while sedentary lifestyle increases, which favors the number of obese people to multiply.

The WHO also estimates that obesity and overweight cause around 2.8 million deaths each year and are closely related to the development of type 2 diabetes. However, in 2017, the study ‘Global Burden Disease’ of the scientific journal The Lancet estimated that this figure was 4.72 million deaths.

According to a United Nations report, in Latin America, 24% of the region’s inhabitants have obesity. In Spain, 40.6% of children between the ages of six and nine are overweight, according to the ALADINO study, which indicates that of overweight children, 23.3% are overweight, and 17 3% suffer from obesity. Regarding adults, the Ministry of Health indicates that the prevalence of obesity is 14.5%, that of overweight 38.5% in people between 25 and 60 years old, which means that one of every two adults’ weight is higher than recommended.

Body composition based on age, sex, and physical activity

There are variations in body composition depending on age, sex, and physical activity. As an example, a person at 25 years of age has 15% of his weight as fat tissue, while at 75, and maintaining a similar weight, he has 30% as such, at the expense of a decrease in muscle mass lean, made up of muscle tissue and bone. 

Adipocytes, present in multiple fatty tissue deposits, are adapted to store this excess energy in the form of triglycerides efficiently and, when necessary, release these deposits in the form of free fatty acids that the body can use. This physiological system, regulated through endocrine and nervous pathways, allows humans to survive in starvation conditions, even for several months. However, when nutrients are abundant and the way of life is passive. With the important influence of genetics, this system increases adipose tissue’s energy stores, with adverse consequences for health.

Obesity can therefore be defined as a clinical syndrome characterized by an increase in adipose tissue proportion about total body weight.

How obesity is calculated based on BMI

The most widely used method to measure obesity is the body mass index (BMI ), equal to weight / height2 (dividing weight in kilograms by height in meters squared). The BMI figures considered normal range between 19 and 26 Kg / m2 (weight/height). A BMI greater than 25 would be considered overweight, while a BMI equal to or greater than 30 is considered obese.

Other ways to quantify obesity are anthropometry (skinfold thickness), densitometry (weight underwater), CT scan, and MRI.

Causes of obesity

In general terms, the excessive accumulation of triglycerides (neutral fats) in adipose tissue ( obesity ) occurs when the caloric balance is positive when more calories are consumed than burned. Obesity is not possible in other circumstances.

However, it is also important to take into account the risk factors that predispose or favor the appearance of obesity, and that help to better understand the reason for this global overweight epidemic:

Genetic factors

In various studies, it has been observed that less than 10% of the children of thin parents are obese, about 50% of the children with an obese parent are obese, and more than 80% of the children whose parents are obese are obese. Thus, a significant correlation between the weight of parents and natural children has been demonstrated. In contrast, this correlation is lower or does not exist when comparing adoptive parents with adopted children.

Nutritional factors

Supercharging can occur at any time of life, but its influence is greater if started at an early age. Nutrition during childhood has acquired great importance in recent years. They demonstrated that a significant percentage of obese children evolve obese adolescents and obese adults. Diets high in fat and carbohydrates can lead to obesity.

Genes influence obesity predisposition when related to specific diets and nutrient availability. For example, starvation prevents obesity, even in people who are more prone to it. Cultural factors related to the composition of the diet and the degree of physical activity are also important. In industrialized societies, obesity is more common in poor women, while in underdeveloped countries, it is in richer women. There is a certain degree of relationship between being overweight and the time they spend watching television in children. Also, society is increasingly sedentary, while physical activity levels have decreased, especially among children and the working population.