The World Health Organisation (WHO) defines obesity as an abnormal accumulation of fat that can be detrimental to health.
Obesity is a chronic disease, caused by different factors, and is of high prevalence, which is associated with a higher risk of developing cardiovascular diseases, a reduction in the quality of life, and an increase in mortality.
Types of Obesity
In adults, the international classification of obesity is that proposed by the WHO, and is based on the Body Mass Index (BMI). Those persons with a calculated BMI equal to or higher than 30 kg/m2 (same for both sexes) are considered to be obese.
Obesity can be measured using the BMI. It is calculated by dividing the weight (kg) by the square of the height in metres. For example, if a man or a woman weighs 120 kg and measures 1.65 metres, they have a BMI of 44 (120 kg / 1.65 x 1.65 = 44). At population level, the BMI has shown a good correlation between body fat (not its distribution) and the risk to health.
Obesity is also classified according to the distribution of adipose tissue in:
Abdominal obesity, visceral. Also called android type, with a predominance of adiposity in the upper half of the body: neck, shoulders, and abdomen. This type of obesity is associated with an increase in the risk of metabolic diseases (type 2 diabetes, atherosclerosis, etc.).
Gluteal-femoral or gynoid obesity. With a predominance of adiposity in the gluteals, hips, thighs, and the lower part of the body.
The strong relationship between fat distribution at abdominal level and cardiovascular disease has led to the clinical acceptance of indirect indicators of abdominal fat, such as the measurement of the waist circumference. The points of reference in Europe for considering abdominal obesity are different in both sexes: in men over 102 centimeters and in women 88 centimeters.
Is Obesity very common?
According to estimations of the WHO, in 2016, more than 1,900 million adults of 18 years or more were overweight, of whom, more than 650 million were obese.
In general, in 2016, around 13% of the world adult population (11% of the men and 15% of the women) were obese.
Between 1975 and 2016, the world prevalence of obesity has almost tripled.
In Spain, according to a study carried out between 2008 and 2010 in the adult Spanish population, the obesity prevalence was 22.9%, higher in men (22.4%), than in women (21.4%), and its prevalence increased with age. This study also showed that 36% had abdominal obesity, which was higher in women (39%), than in men (32%).