Obesity is excess fat (adipose tissue) in our body.
Normal values of body fat are 12 to 20% in men and 20 to 30% in women. Thus, in numerical terms, defined as obese subjects to those with body fat percentages above 20% in men and 30% in women. Values between 21 and 25% in men, and between 31 and 33% in women, are considered borderline (overweight).
The determination of this percentage is not easy or quick to get, so in everyday use an index that is called body mass index (BMI, weight in kilograms divided by height in meters squared). To define obesity in adults (aged 18 years) is accepted as the cutoff value of BMI of 30 kg/m2 or higher, although higher values have been set to the 85th percentile of the population distribution of reference. BMI values of 25 to 29.9 kg/m2 indicates overweight. In children and young people are used as criteria to define overweight and obesity values for age and sex specific percentile of BMI 85 and 97, respectively, using the tables published by Cole in 2000.
Obesity depends on intake (calories each day enter our body through food) and energy consumption or expenditure we do (by physical activity or energy expenditure derived from metabolic reactions that continuously produced in our body). We consider our body weight as if it were a scale with two pans, one pan is the energy gain (intake) and the other is the energy loss (consumption). On each of these two dishes are factors that add weight and others that take away weight, for example, the physical exercise is a weight factor that removes spending saucer, while inactivity is a factor adds weight to spending saucer (fatter), and likewise, a high calorie dish add weight gains or inputs, and a state of famine will make this dish even less. The sum of all the factors that influence these dishes will make the scale is balanced (normal weight) or unbalanced (overweight or obese at one end, or at the other extreme thinness).
However, you do not need a big (and obvious) intakes of food to gain weight, with only slight excess calories each day (no obvious gains) but held for several years leads to gains of several kilos.
We know that there are hormonal factors and factors that regulate nerve one of those pans of the scale, the scale of the energy inputs or income, ie appetite. For example, hormones such as leptin, which suppresses the appetite and increases energy expenditure. Or nervous factors psychological sphere, as cultural beliefs about the cult of the body of our society and punishes obesity and equates thinness with harmony, beauty, prestige and success, which act by inhibiting appetite and we will eat less and lose weight. Or if we have a full stomach substances occur in the gastrointestinal tract, such as cholecystokinin (synthesized in the small intestine) or peptide YY (synthesized in the small intestine), which reaches the brain and indicates the cessation of intake of more food, or the contrary, ghrelin, synthesized in the stomach and stimulates eating.The blood sugar have, when descending a long, causes hunger. All these signals (hormones, psychological factors, cultural factors, nerve impulses …) come to a brain structure called the hypothalamus, which is the central regulator of appetite.
Our genes may regulate signaling through the show and can help a person to be obese, but except in very limited circumstances, are not responsible for obesity. For example, the lack of leptin in hypogonadotropic hypogonadism, a rare genetic disease that causes more obesity among other alterations.
There are other more common diseases and nongenetic where obesity is another element. This is called secondary obesity. Examples of this are certain endocrine problems obesity and Cushing’s syndrome (increasing cortisol), hypothyroidism (thyroid hormone deficiency), certain forms of dwarfism (by hypothalamic lesions that cause growth hormone deficiency), the insulinoma , polycystic ovary syndrome, and lesions in the hypothalamus (craniopharyngioma, trauma or infection).
In summary, primary obesity, the most common, has no known origin and is due to increased energy intake, to decrease their consumption, or a combination of both. In the development of this obesity involving genetic, metabolic, hormonal, and environmental nervous. Obesity has an identifiable secondary and in some cases, medically treatable and potentially curable.
Obesity causes no symptoms, except the visual and aesthetic. However, long term, produce serious adverse effects on our health.
Visually we discuss various types of obesity, according to where the fat is located: central obesity speak when fat accumulates in the abdomen and covers the different tissues and organs (heart, kidneys, liver, etc.) And peripheral obesity when fat accumulates in the buttocks, thighs and arms.
Health problems associated with obesity are:
This determines a person at greater risk of becoming ill, worse quality of life and shortens life expectancy by several years. However, the type of obesity associated with increased risk of illness and death is central obesity.
The diagnosis of obesity is often visual. But how do we measure and confirm scientifically that excess weight?
Three anthropometric data that are of utmost importance to assess the degree of obesity, weight, height and circumference or waist circumference. With them we prepared the following indexes:
With a simple tape measure and a scale we can get these rates. We can, however, use other methods which are more expensive and more complex and are not routinely used in clinical practice. For example, impedance techniques to determine the percentage of body fat of an individual. The analysis of the measured body impedance of body tissues opposition to the passage of an electric current (body impedance), which depends primarily on the content of water and minerals. Lean body mass is a good electrical conductor (has low impedance), while fat acts as an insulator (has high impedance). The body impedance measurement provides a direct estimate of total body water, lean mass and body fat. Normal values are around 12 to 20% in men and 20 to 30% in women. Other techniques include computed tomography (CT) and abdominal MRI, which can diagnose excess abdominal fat that accumulates around the tissues and organs (which is the pathological fat) index is used visceral fat area / area subcutaneous fat, a BMI greater than 0.4 define visceral obesity. Although these techniques have their uses in research protocols.
In obesity is also important to rule out the same secondary causes, thyroid malfunction or excessive adrenal gland function.
In the development of obesity involving genetic, metabolic, hormonal and environmental latter being modular we can modify our lifestyles. We must not forget that changing lifestyle habits also change the alterations associated with obesity, such as hypertension, diabetes mellitus and other aforementioned.
The primary goal of treatment should be to reduce weight in a long time and then got loss maintenance. A short-term goal is the initial weight loss of 10% at a rate of 225-1000 grams a week, although this should always be individualized according to each patient in obese patients may be due more to lose in less obese patients . We describe in more detail how these losses must be made in another chapter.
The change in diet includes a reduction in total calorie intake. The measures passed by avoiding a sedentary lifestyle, exercising regularly, eating correct errors and make a balanced diet.
Your doctor and dietitian will tell you what steps to follow and how to develop them.
With regard to food there are some considerations that are important to note. Thus, it is important to know that alcohol is a non-negligible source of calories and light foods also contain calories.
They should avoid very restrictive diets, because although significant losses may influence weight, these losses are also lean mass, involve restriction or lack of certain nutrients and are not well accepted in the medium and long term. And what it is to change our eating pattern and maintain this change throughout life.
The use of dietary fiber before meals may be useful to decrease appetite by producing a satiating effect, we can take some nuts or guargum prepared before you start eating.
Exercise intensity should be moderate, daily, lasting half an hour a day. Recommended activities like walking up the stairs instead of the elevator, walk to the next stop of the subway or bus and get off one stop earlier, walking with a group of friends, cycling, swimming, etc..
These changes should be based on a change in the patient’s behavior. This means it is easy to start changing your diet and start doing some physical activity, but quickly loses interest and becomes the previous pattern of sedentary lifestyle and unbalanced diet. This requires recommending self-monitoring techniques used (for example, keeping a journal, weigh and measure the food and physical activity is performed), stimulus control (like not eating or traveling watching TV, using plates of dimensions smaller), improve self-esteem and body perception.
Keep in mind that the achievement of results, losing weight and keeping it off, is a slow process, not to despair the person and often must involve the physician, nurse and a nutritionist.
Changes in lifestyle cause a modest decrease (3 to 5 kg) in weight. So in some cases it will be necessary to use drugs or bariatric surgery.
Should consider drug treatments as an adjunct to lifestyle changes in individuals with a BMI greater than 30 kg/m2 input and also in those individuals who have been ineffective lifestyle changes to lose weight.However, the drugs should be added to lifestyle changes and not be replaced.
There are two types of drugs for treating obesity, the physician may use: sibutramine, which acts on the central nervous system, and decreases the appetite and orlistat, a drug that prevents absorption of fat in the digestive tract.
We will have to think of a weight reduction surgery in severely obese individuals (those with a BMI over 40 kg/m2) or in individuals with moderate obesity (BMI 35 to 40 kg/m2) but have any other medical problems serious.
The weight loss is achieved using these techniques due to decreased caloric intake (limiting the amount of food that can retain the stomach, thereby sending satiety signal to the hypothalamus with small intakes).With some surgeries also prevents the absorption of macronutrients (causes malabsorption be controlled).
These methods typically obtain a total average loss of 30 to 35% of body weight, which is maintained in more than half of patients within five years.
The intragastric balloon is not really surgery. Endoscopic involves placing a saline-filled balloon or air in the stomach, so that the stomach is filled with less food satiety and appears sooner. Average loss can reach 15 to 20 kg over a period of 6 months, although there is no long term results if these weight losses are kept.
To keep the weight within normal limits that we have to get energetic equilibrium, that the calories we eat and we spend must be approximately the same. This should be achieved with food and physical activity.
Moreover, preventive measures should begin in childhood and must take place within the family and in schools continued.
Being overweight usually indicates the presence of a higher amount of body fat. Obesity is not just a cosmetic issue, it is a serious medical problem. The fat, especially that accumulates in the abdomen, is associated with an increased risk of diabetes mellitus, hypertension, cardiovascular diseases, respiratory diseases and more, and die for it. We must make every effort to reduce weight with the help of a nutritionist and a doctor, and with drugs and surgery when necessary.
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