Obesity
The Obesity is a chronic disease characterized by an increase in fat mass and, consequently, an increase in weight. This results in an increase in the body's energy reserves in the form of fat. The term "chronic" is applied because it belongs to the group of diseases that we cannot cure with the current therapeutic arsenal available today.
It is important not to confuse excessive weight with obesity. For example, a bodybuilder may have a high weight, but at the expense of muscle mass; heart failure can cause fluid retention, leading to an increase in weight, and the same can happen with liver and kidney failure.
Classification
Despite its limitations, Body Mass Index (BMI) is the simplest method for detecting the presence of obesity in most people. According to this index, a person can be classified as:
More recently, it has been shown that the distribution of obesity is also associated with cardiovascular risk. The accumulation of fat in the abdomen, known as abdominal obesity or visceral obesity, is associated with an increased risk for the development of diabetes, cardiovascular diseases, and mortality compared to fat accumulation in the hips, buttocks, legs, or other locations. This appears to be because the fat within the abdomen has special characteristics that make it more harmful. The International Diabetes Federation considers that abdominal obesity exists in individuals of European descent whose waist circumference is greater than 94 cm in men and 80 cm in women. American criteria indicate that abdominal obesity is present when the waist diameter exceeds 102 cm in men and 88 cm in women.
Gastric Bypass
Currently, the most common procedure performed worldwide is the Roux-en-Y gastric bypass, which combines both restrictive and malabsorptive techniques. The procedure involves dividing the stomach into two portions, one small portion consisting of 25 to 30 ml, which is connected directly to a jejunal loop located at the angle of Treitz, about 150–200 cm from the created reservoir. This design prevents food from passing into a large portion of the stomach and the duodenum, where absorption is reduced. Additionally, since the stomach pouch is small, it does not allow large amounts of food to enter; this is known as the alimentary loop.
Dramatic and rapid weight loss can be observed in patients who undergo this procedure, as they usually lose between 65% and 80% of their excess body weight in the first year, and this loss can be sustained for up to 16 years post-intervention. Gastric bypass can significantly improve or resolve some of the comorbidities caused by obesity and reduce long-term mortality.
Gastric Sleeve
The gastric sleeve is a partial gastrectomy in which most of the greater curvature of the stomach is removed, creating a tubular stomach.
It is considered a safer procedure since it has a reduced risk of internal herniation and malabsorption of proteins and minerals. The antrum is divided approximately 2 to 6 cm from the pylorus, and a sleeve is created around a 32 to 40 French tube. The resulting tubular stomach is small, has reduced capacity, is resistant to narrowing due to the absence of the fundus, and contains few ghrelin-producing cells, a hormone involved in appetite regulation.
English 
Spanish