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Médico Bariátrico. Obesity Science. CDMX. México.

Médico bariátrico

Find out how bariatric surgery can help you get your life back

Defining obesity

It is an abnormal or excessive accumulation of body fat caused by an imbalance between energy intake and consumption (calories). It is no longer considered a cosmetic problem caused by overeating and lack of self-control. The World Health Organization (WHO), together with national and international medical and scientific societies, now recognize obesity as a chronic progressive disease resulting from multiple environmental and genetic factors.

Obesity is extremely expensive not only in terms of the economy, but also in terms of individual and social health, longevity, and psychological well-being. Due to its progressive nature, obesity requires lifelong treatment and management.

Causes of obesity

Does not have a single cause, and it is not only result of the responsibility of the individual. Its etiology is complex and multifactorial, involving biological (genetics and metabolism), psychological or behavioral (unhealthy lifestyle), environmental, economic and sociocultural factors that together cause significant changes in lifestyle.

Nowadays, it is recognized that a person may not have any control over the social determinants that favor the development of obesity, replacing the perception that obese individuals are solely responsible for their condition.

Measuring obesity

Obesity is characterized by an excessive accumulation of body fat. There are a variety of instruments available to assess the amount of fat versus lean tissue in the body. However, due to the cost  From these instruments and at the time required for body fat assessments, obesity is clinically defined by measures that "estimate" adiposity from body weight, body build, and height:

  • Ideal body weight (IBW)

  • Body mass index (BMI)

Ideal body weight (IBW)

One of the estimates for body size is ideal body weight (IBW), a number obtained from the "Metropolitan Life Insurance Company" table. The IBW table  is based on mortality data and requires knowledge of body weight and frame  body, a measure that many experts consider arbitrary. Using this table, overweight and obesity are defined by the percentage of excess weight of IBW.

Body mass index (BMI)

Body mass index (BMI) is another measure used to define overweight and obesity, and is considered a more accurate estimate of body fat than IBW. Large population studies find that BMI generally reflects the amount of excess body fat an adult has, although there are certain exceptions, such as the BMI of a woman who is pregnant, an athlete, a bodybuilder, or older people. However, BMI does not necessarily take into account a person's fat distribution (abdominal versus  peripheral) and is not a good measure of the metabolic activity of a person's adipose tissue.

Obesity prevalence

According to the WHO, 65 percent of the world's population lives in countries where overweight and obesity kill more people than underweight. Approximately 500 million adults in the world are affected by obesity and one billion are affected by being overweight, along with 48 million children.


In Mexico, 35.6 % of children from 5 to 11 years old, 38.4 % of adolescents aged 12 to 19 years, and 76.8 % of women and 73.0 % of men aged 20 and over, are overweight or obese. The prevalence increased from 21.4 % in 1992, to 75.2 % in 2018.


In the United States, epidemiological data shows that 34 % of adults over the age of 20 are affected by obesity and 68 % are overweight. Obesity affects 10 % of children between the ages of two and five, 2 % of those between the ages of 6 and 11, and 18 % of adolescents.

Positive energy balance

A positive energy balance causes weight gain and occurs when the number of calories consumed (energy consumption) exceeds the number of calories the body uses (energy expenditure) in performing basic biological functions, daily activities, and exercise. It can be caused by overeating or not having  enough physical activity. However, there are other conditions that affect energy balance and fat accumulation that do not involve overeating or sedentary behavior.

Weight gain

Weight gain is another factor that contributes to weight gain or, in other words, obesity "begets" obesity, which is one of the reasons the disease is considered "progressive."


Weight gain causes a series of hormonal, metabolic, and molecular changes in the body that increase the risk of increased fat accumulation. Such biological changes  They reduce the body's ability to oxidize (burn) fat for energy, increase the conversion of glucose (carbohydrates) into fat, and increase the body's ability to store fat in fat storage depots (adipose tissue). This means that more of the calories consumed will be stored as fat.

Obesity-related conditions

Several other conditions associated with obesity contribute to the progression of the disease. Obesity reduces mobility and the amount of calories that would be burned during physical activity. Weight gain can also cause distress.


The duration of sleep is reduced by weight gain due to a number of conditions that deteriorate the quality of sleep.  The shortened duration of sleep, in turn, produces certain hormones that stimulate appetite and increase fat absorption.


Weight gain also contributes to the development of other diseases such as hypertension, diabetes, heart disease, osteoarthritis, and depression.


A low calorie diet is the main treatment for overweight and obesity, but the diet also contributes to the progression of obesity. Losing weight in the diet causes biological responses that persist in the long term and contribute to weight regain. One of these responses affects the energy balance. Another involves changes in fat metabolism that reduce the body's ability to burn fat and increase the ability to store it.  in fatty deposits.

Altogether, losing weight in the diet reduces the use of fat for fuel and increases the storage capacity of unused fat. These changes lead to a progressive increase in fat accumulation, even if the individual is not overeating.

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