Mauro Czepielewski, MD., Ph.D. in Endocrinology – São Paulo State University School of Medicine (UNIFESP). Vice-Director of the State University Rio Grande do Sul School of Medicine (UFRGS). Associate Professor – Internal Medicine Department/UFRGS.



Excess weight


What is it?

The illness denominated obesity is a disorder characterized by the excess accumulation of body fat, coupled with health problems, which damages an individual’s health.

How does it develop or how is it acquired?

In the different stages of its development, the human organism is the result from diverse interactions between its genetic heritage (inherited from the family), the socioeconomic, cultural and educational background, as well as the individual and family setting. Therefore, a certain individual has a number of unique characteristics that distinguish them, especially when it comes to their health and nutrition.

Obesity is the result from many of these interactions, in which the genetic, environmental and behavioral aspects stand out. Thus, children with both parents being obese have a high risk for obesity; also, certain social changes stimulate weight gain in a whole group of people. Recently, a number of scientific data regarding the different mechanisms by which one puts on weight have been amassed, increasingly demonstrating that this condition is often associated with different factors.

Regardless of the importance of these different causes, weight gain is always associated to an increase in dietary intake and a reduction in energy expense corresponding to such intake. The increase in intake may arise from the amount of food ingested or changes in its quality, resulting in an increased total caloric intake. The energy expense, by its turn, may be associated to genetic characteristics or be dependent upon a set of clinical and endocrine factors, including diseases in which obesity results from hormonal disorders.

What does one feel?

Excess body fat doesn’t cause direct signs and symptoms, except when it reaches extreme values. Irrespective of the severity, the patient presents significant esthetic drawbacks, accentuated by the current beauty pattern which demands a body weight that is even lower than that accepted as normal.

Obese patients have restrained movements, tend to be contaminated with fungi and additional skin infections in their fat folds, having several complications, at times, severe. Moreover, they strain their spine and lower limbs, presenting in the long run degenerations (arthrosis) in the joints of the spine, hip, knees and ankles, in addition to superficial and deep varicosis with repetition ulcers and erysipelas.

Obesity is a risk factor for a number of diseases or disorders that can be:

Diseases Disorders
Arterial hypertension lipidic disorders
Cardiovascular diseases hypercholesterolemia
Cerebrovascular diseases HDL decrease (“good cholesterol”)
Diabetes Mellitus type II insulin increase
Cancer glucose intolerance
Osteoarthritis menstrual disorders/infertility
Choledocholithiasis sleep apnea

Thus, obese patients present a severe risk for a number of diseases and disorders, which leads to a significant reduction in their life expectancy, especially when suffering from morbid obesity (see below).

How does the doctor diagnose it?

The most widely recommended method of body weight assessment for adults is the BMI (body mass index), also recommended by the World Health Organization. Such index is calculated by dividing the patient’s weight in kilograms (kg) by the square of his/her height in meters (see item “Body Assessment” on this site). The value thereby obtained establishes the diagnosis of obesity and also characterizes the associated risks as follows:

IMC ( kg/m2) Risk Level Type of obesity
18 a 24,9  Healthy weight Absent
25 a 29,9  Moderate Overweight (Pre-Obesity)
30 a 34,9  High  Obesity level I
35 a 39,9 Very high Obesity level II
40 or above Extreme  Obesity level III (“Morbid”)

As observed, the normal weight, in an adult over 20 years of age, varies according to their height, which enables us to also establish the lowest and highest thresholds of body weight for different heights according to the following table:

Height (cm)  Lowest weight (kg) (kg) Highest weight (kg) (kg)
145  38  52
150  41  56
155  44  60
160  47  64
165  50  68
170  53  72
175  56  77
180  59  81
185  62  85
190  65  91

Obesity also has some characteristics that are important for the repercussion of its risks, depending upon the body segment in which fatty deposition prevails, being classified as:

Diffuse or general obesity
Android or centripetal obesity, in which the patient shows a body shape tending to resemble an apple. It’s associated with a greater deposition of visceral fat and is intensely related to high risk for metabolic and cardiovascular illnesses (Plurimetabolic Syndrome)
Gynecoid obesity, in which fat deposition predominates at the level of the hip, causing the patient to show a body shape similar to a pear. It is associated to a higher risk for arthrosis and varices.

This classification is very important, as it defines some risks, and, for this reason, an index denominated Waist-Hip Ratio was created, obtained by dividing the waist circumference by the patient’s hip circumference. As a rule, it is accepted that there is presence of metabolic risks when the Waist-Hip Ratio is higher than 0.9 in men and 0.8 in women.

The mere measure of the waist circumference is also considered an indicator of risk for obesity complications, being established according to patient gender:

  Increased Risk Highly increased risk
Male  94 cm 102 cm
Female  80 cm 88 cm

Body fat can also be estimated by measuring skinfolds, mainly at the level of the elbow, or using methods such as Bioimpedance, Computerized Tomography, Ultrasound and Magnetic Resonance. These techniques are useful in some cases, in which the aim is to determine the body constitution more thoroughly.

In children and teenagers, the diagnostic criteria depend on the comparison of patient weight to standardized curves, in which are expressed the normal values of weight and height for the patient’s exact age.

According to its causes, obesity may still be classified as in the following table:

Classification of obesity according to its causes

“Junky food” diets

Mandatory disability

Old age

Cushing’s syndrome


Polycystic ovary



Growth hormone deficit

Insulin increase and insulin-producing pancreatic tumors

Associated to chromosome X

Chromosomal (Prader-Willi)

Lawrence-Moon-Biedl’s syndrome

Nutritional disorder obesity

Fat-rich diets

Physical inactivity obesity

Sedentary habits

Obesity secondary to endocrine alterations

Hypothalamic syndromes

Secondary obesity

Drugs: psychotropics, corticoids, tricyclic antidepressants, lithium, phenothiazines, cyproheptadine, medroxyprogesterone Hypothalamic surgery

Obesity of genetic origin

Autosomal recessive

It must be stressed that the medical evaluation of an obese patient must include detailed patient history and clinical examination, and, according to this evaluation, the doctor will either investigate or not the diverse causes of the disorder. Thus, specific exams for every situation will be necessary. If the patient presents obesity “only”, the physician may proceed to a minimal laboratory evaluation, including hemogram, creatinine, fasting glycemia, uric acid, total cholesterol and HDL, triglycerides and standard urine test.

In the eventual presence of arterial hypertension or suspicion of associated cardiovascular disease, specific exams can also be conducted (chest x-ray, electrocardiogram, echocardiogram, ergometric test), which will be useful especially for prospective recommendations of exercises for the patient.

Based on this initial approach, it may be possible to identify a condition in which excess weight shows a significant behavioral component, perhaps entailing psychiatric evaluation and treatment.

Based on the several considerations made above, we deem important to point out that an obese patient, before beginning any treatment procedure, should consult with a physician with the purpose of elucidating all details pertaining to their diagnosis, as well as the different outcomes from their disorder.

How is it treated?

The treatment of obesity necessarily involves dietary reeducation, an increase in physical activity, and, occasionally, the use of some adjunctive medications. Depending upon the condition of each patient, behavioral treatment involving a psychiatrist may be indicated. In cases of obesity secondary to other diseases, the treatment must addressed the disorder cause firstly.

Dietary reeducation

Irrespective of the proposed treatment, dietary reeducation is vital, since it is the means by which we’ll reduce the total caloric intake and the resultant caloric gain. This procedure may need emotional or social support by specific treatments (individual, group or family psychotherapy). In this situation, emotional support groups that help people lose weight are widely known.

Apart from this support, however, dietary counseling is fundamental.

Among the different forms of dietary counseling, the most scientifically accepted is the balanced hypocaloric diet, in which the patients receive a diet program calculated with calorie quantities dependant on their physical activity, with five or six daily meals, containing approximately 50-60% of carbohydrates, 25-30% of fats, and 15-20% of proteins.

Very uptight diet programs are not recommended (with less than 800 calories, for instance), since these pose severe metabolic risks, such as metabolic alterations, acidosis and arrhythmia.

Diets with only a few foods (e.g., pineapple diet) or liquids only (water diet) aren’t recommended either, as they present several problems. Diets with excess fat and protein are similarly quite disputable, as they worsen the patient’s fat alterations, in addition to increasing fat deposition in the liver and other organs.


It’s important to bear in mind that physical activity is any body movement produced by skeletal muscles that results in energy expense, and that exercise is a physical activity planned and structured with the purpose of improving or maintaining the physical conditioning.

Exercising brings a number of benefits to obese patients, improving the dietary treatment performance. Amongst the different effects are included:

decreased appetite,
increased action of insulin,
improvement in fat profile,
improvement in wellness and self-esteem.

The patient must be advised to work out regularly, for a minimum of 30-40 min, four times a week at least; the exercises must be mild at first, and, subsequently, moderate. This activity, in some situations, may require a professional and specialized environment, and, most of the time, the simple recommendation of taking a walk regularly already brings great benefits, being included in what we call patient “lifestyle change”.


The use of medications as an aid to the treatment of an obese patient must be carried out carefully, not being, as a rule, the most important aspect of the measures implemented. Medications whose commercial brand is known must be preferred, avoiding the use of manipulated formulations. Every specific medication, depending on its pharmacological composition, poses several side effects, some of them being quite severe, such as arrhythmia, psychotic outbreaks and chemical addiction. That’s why they should be used only in special situations, in agreement with the physician’s judicious judgment.

The medications currently available for treating obesity can be classified according to their mode of action as shown below:

Anorexigenic medications

Mode of action Name of Active Substance
Catecholaminergic phentermine,phenproporex,amfepramone (diethylpropion), mazindol, phenylpropanolamine
Serotoninergic; Fluoxetine, Sertraline
Serotoninergic  Sibutramine
Thermogenic  Ephedrine, caffeine, aminophylline
Fat absorption inhibitors Orlistat

As regards the treatment of obesity with medications, it’s important to underscore that the use of a number of substances has no scientific support. Amongst these are included diuretics, laxatives, stimulants, sedatives and other products frequently recommended as “weight-losing formulas”. This strategy, in addition to being dangerous, doesn’t bring benefits in the long run, leading the patient to return to their previous weight or even put on more weight than before.

How is it prevented?

A healthy diet should always be encouraged in childhood, preventing children to be overweight.

The diet should be included in the general principles of a healthy lifestyle, in which physical activity, leisure, suitable affective relationships and an organized family structure are included.

For the previously obese patient who succeeded to lose weight, the maintenance treatment must include constant physical activity and a long-term healthy diet. These goals will only be achieved if they’re coupled with a general change in the patient’s lifestyle.