In general, an obese individual is one who has excess weight. The medical term obesity is defined as an excess body fat accumulated in the adipose tissue due to a positive energy balance, which in turn means that the individual consumes more food than energy spent. This term is associated to “overweight” in sedentary individuals that have not yet reached the category of obesity. In athletes, the opposite occurs, where overweight is due to a development (hypertrophy) of muscle mass, followed by normal or even low levels of body fat.


 Obesity is considered as the epidemic of the 21st century, being one of the most common diseases in the world. Approximately 14% of children, 15% of young adults and 35% of the elderly present this problem. Furthermore, it is estimated that these values will double in less than 50 years. This change in body composition is due to our current lifestyle (not considering genetic alterations, which also play an important, although minor, role). One of the causes is the industrialization, which starting in the 80s has abused of the use of saturated fats (coconut or palm oil, as well as animal fats). This has caused a surge of a new type of business in the food industry, through the development of processed baked goods and the creation of fast-food restaurants. They allegedly use vegetable oils, but have been modified at the molecular level (“trans” fats), as well as simple sugars. At the same time as society changed its eating habits, it was also becoming more sedentary, watching more hours of TV and performing static jobs. This abandonment of traditional diets along with a more sedentary lifestyle has ultimately resulted in an unstoppable increase of overweightness and obesity.

Therefore, the decrease in physical activity and increased sedentariness are key aspects. In this manner, the average daily energy expenditure nowadays is much lower than half a century ago. This problem will continue rising, as the World Health Organization (WHO) has indicated that the rate of obesity will continue growing in the following years.

Besides genetic predisposition and an unhealthy lifestyle, there are other reasons that an individual´s body fat content can increase. There are certain diseases that can cause body weight increase without an increase in food consumption, for example hypothyroidism. In this disease, the thyroid gland (located in the neck region) does not produce sufficient hormone, resulting in decreased metabolism, less calorie consumption and therefore fat accumulation. Another example is Cushing syndrome, where the suprarenal glands (located over the kidneys) produce more cortisol than normal. This excess, due to several reasons, also results in fat accumulation. The presence of tumors in regions in the brain responsible for satiation can also induce obesity. However, these syndromes have a lower incidence than obesity, and must be diagnosed and treated by a medical specialist.

Pharmaceutical drugs are another factor that can induce increased body weight. In fact, corticoid (cortisone) treatments, which are widely used to reduce inflammation, among other functions, can increase body weight as a side effect.

Anti-depressants also have this effect. Furthermore, individuals that stop smoking also generally gain weight. This is due to the fact that they present anxiety, and try to alleviate it by eating. Nicotine also reduces appetite, which is reverted when they stop smoking. It is estimated that in the first months the individuals gain 2-4 kg. However, this is reversible if the individual controls his/her diet.

Determination of body fat and types of obesity

Body fat content can be determined by different methods, although the most extended is the body mass index (BMI). It is widely used as it can be applied to the majority of the population, but not athletes, pregnant women, children nor certain patients. It is defined as the quotient between weight in Kg and height in meters squared:

                           Weight (Kg)

             BMI = ——————-

                             Height2 (m)

For example, an individual measuring 1.65 m and weighing 60 Kg would have a BMI of:

BMI = 60 / (1.65 x 1.65) = 22 Kg/m2

This measurement is independent of gender and age.

The WHO has established the range of BMI values which correspond to thinness, normal weight, overweight and obesity. This classification is based on the studies relating mortality risk and BMI. The lower risk for mortality correspond to BMI values between 20 and 25, increasing to 27 in the elderly, whereas above or below these levels the risk increases.

The range considered for overweight and obesity, considering the BMI, is the following:

Overweight: BMI of 27-29 kg/m2. This poses no health problem for the individual.

Obesity type I: BMI of 30-34.9kg/m2. In this range the risk for cardiovascular disease exists, such as diabetes, arterial hypertension, dislipemia, etc.

Obesity type II: BMI of 35-39.9 kg/m2. Moderate-high risk for cardiovascular disease.

Obesity type III (morbid) and type IV (extreme): BMI of 40-49.9 kg/m2 in the first case, and > 50 kg/m2 in the second. These two types of obesity are the most dangerous, as besides the onset of at least one cardiovascular disorder along with disability/handicap, there is an increased mortality risk.

There are fundamentally two types of obesity. Central (android) obesity is characterized by a notable accumulation of fat in the middle region of the body (abdomen). This is more prevalent in men and post-menopause women, and is associated with an increased risk for cardiovascular disease. The measurements to value cardiovascular risk are:

1) Waist circumference, where a value over 88 cm in women and 102 cm in men are considered at risk.

2) Waist to hip ratio, obtained by the dividend of the waist and hip circumferences. A value above 0.8 in women and 0.95 in men is considered a high risk for cardiovascular disease.

The second type of obesity is called gynoid (peripheral) obesity. In this case, the fat is accumulated in the inferior limbs, being more frequent in women. Although this type of obesity is considered a lower health risk, as it does not directly affect any organ, it can cause certain problems in the kidneys, uterus and bladder. Other complications include varixes, circulatory problems, chronic fatigue, arthrosis, etc. The location of this fat makes it more difficult to eliminate, making weight loss an arduous task. Finally, independently of the risk that these types of obesity present, it is always recommendable to avoid their appearance.

Diseases associated with obesity

Medical_complications_of_obesityCardiovascular diseases include coronary diseases (ischemia, heart attack, angina pectoris), hypertension, dyslipidemia (high levels of cholesterol and triglycerides) as well as cardiac failure. Individuals with obesity have a 1.5-2.5 higher risk of these diseases. One of the reasons for this is that obesity increases the odds of cardiac problems and hypertension, as the increased weight forces the heart to work harder to pump blood so that it may reach all the tissues of the body. This in turn increases the pressure of the blood on the arterial walls (arterial pressure or tension) and thus cause hypertension.

The decrease in body weight can help the heart to return to normal levels, avoiding in this manner heart failure. High levels of LDL (“bad” cholesterol) and low levels of HDL (“good” cholesterol) in blood, as found in the obese population, also increases the risk for arteriosclerosis. This disorder consists in the progressive thickening and rigidness of the blood vessel walls, causing the arterial diameter to decrease. Furthermore, the risk for the formation of small blood clots also increases, which can block capillaries, and if this occurs in the brain or heart, can cause a stroke or heart attack.

Although cardiovascular problems are the most prevalent in the obese population, there are other associated pathologies that must be considered:

  • Sleep apnea: this disorder is characterized by pauses in breathing, or superficial breathing, while sleeping. It is very frequent in overweight individuals as the excess weight exerts an additional pressure on the lungs when the individual lays on the bed.
  • Hiatus hernia: this is an affection characterized by a portion of the stomach extending towards the interior of the thorax, through the diaphragm. Gastric distension, very frequent in obesity, favors this affection. This is accompanied by acid reflux and therefore digestive discomfort.
  • Kidney stones: these are solid masses of small crystals derived from substances that precipitate such as calcium salts or oxalates present in the urine. These stones generally produce a large amount of pain. Unbalanced diets, such as those consumed by obese individuals, can increase the risk.
  • Gallbladder stones: these are solid masses in the gallbladder composed of biliary salt precipitates, as a consequence of high levels of cholesterol. This affection generally occurs in individuals with cholesterol-rich diets.
  • Fatty liver: this is due to the accumulation of fat in the hepatocytes (liver cells), also called hepatic steatosis, causing irregular function in the liver. An excess of fat in the diet causes increased fat levels in the blood that later is accumulated in various organs, including the liver. These fat deposits cause liver malfunction, giving rise to this disorder.
  • Type 2 Diabetes: this pathology is caused by the deficient production of insulin, the hormone that regulates blood glucose levels (glycemia). As a consequence there is an increase in blood glucose levels (hyperglycemia). The cause of this disorder in obese individuals is the toxicity of the nutrients. Unbalanced diets with high levels of glucose and fatty acids can eventually kill the cells responsible for producing insulin (beta cells of the pancreas), giving rise to this disorder and in certain cases require the use of insulin injections. Insulin resistance is a stage previous to diabetes, and if it is detected early, can be treated with an adequate diet, exercise and in certain cases pharmaceutical drugs.
  • Colon cancer: this pathology is caused by the appearance of malignant cells in the intermediate region of the colon (in the large intestine), where the feces are stored before being expulsed. As many obese individuals present constipation problems, the prevalence of this type of cancer in this population is high.
  • Pancreatic cancer: as in the previous case, this pathology is caused by malignant cells that cause the organ to malfunction, disrupting hormone and digestive enzyme secretion. The onset of this pathology in obese individuals is due to unhealthy lifestyles, excess weight and suffering from diabetes.
  • Uterus cancer: this is one of the most common types of cancer in women. Diabetes increases the risk for this disease, as well as high blood pressure or estrogen levels. All these risk factors are related to obesity.
  • Prostate cancer: very frequent in men over 50 years of age. One of the factors that can increase the risk for this disease is a diet high in animal fats.
  • Movement and joint problems: Obesity can cause major problems in the joints, especially in the ankles, knees, hips and spinal cord. This in turn accelerates deterioration and consequently movement loss. Furthermore, the risk of lesions increases. The pathology can evolve into joint pain, which causes sedentarism and inactivity, making it more difficult for the individual to perform exercises to lose weight.
  • Skin ulcers: Obesity alters the epidermal barrier of the skin, increasing its dryness and causing water loss. Also, the skin folds that appear (such as the famous “love handles”) have little ventilation and suffer from friction, favoring the formation of ulcers.
  • Psychological problems: In general, an obese individual is more prone to depression and low self-esteem, which in turn can further worsen the situation. Therefore, in order to guarantee the success of the treatment, it is necessary to use an interdisciplinary approach, ensuring that the obese individual has the appropriate psychological support.

Obesity Treatment

Obesity can be treated in several ways, depending on its severity. Generally, a balanced, hipocaloric diet (less energy in the diet than the organism requires) together with an increase in physical activity is sufficient. This should be accompanied by psychological support to motivate the individual to the new lifestyle. Alternatively, there are certain pharmaceutical treatments that reduce the intestinal absorption of fat in the diet, as well as anorexigenic drugs (that reduce or eliminate appetite), which in the latter case have many secondary effects. Furthermore, gastric or intestinal surgery can also be efficient. These two cases (pharmaceutical drugs and surgery) should be performed and supervised under strict medical control. Instead, as long as the individual is capable of movement, it is recommended to change lifestyle, introducing a healthy diet and increasing daily activities, under professional guidance.obesity no yes