Obesity information

Obesity represents a well-described medical condition in which a certain individual becomes overloaded with excessive adipose tissue that he does not require by any chance. On the contrary the additional fat storage only impacts him in a negative way, statistically increasing the chance (sometime significantly) of the individual experiencing other secondary complications throughout his life. Compared to other medical conditions obesity seems to be a flourishing phenomenon of the 20th and 21st centuries, other similar cases being the HIV-epidemic and the TB-epidemic.

Although it was previously thought that obesity was far more incident in well-developed countries, in recent years studies have shown that both developing countries have not been spared by the occurrence of highly overweight population. This is because although apparently a paradox, junk food has become cheaper and cheaper as industrialization brought machinery and facilities that could easily process primary products. Instead, natural and only slightly processed food became rarer and much more expensive in a constant effort to supply the ever-growing population with a condensed, oversaturated in calories food that could easily and quickly manage their energy expenditure. This however has lead to an irrational lack of balance in the way that foods are built, leading to an altering in the metabolism and as a consequence in an astonishing incidence of the overweight and obesity problems.

Over the time the kilogram surplus has been categorized in many ways. Today we mainly rely on a classification that is subsided to calculating the so-called Body Mass Index (BMI). The BMI is obtained by dividing the individual's weight expressed in kilograms by the quadratic of his height expressed in meters. According to the value obtained (measured in kilograms per square meters) he can then be included into one of the following categories: underweight (<18.5), normal weight (>18.5, <25), overweight (>25, <30), class I obesity (>30, <35), class II obesity (>35, <40) and class III obesity (>40). Some physicians call the last class morbid obesity due to the high incidence of complications that usually arise in these patients lifetime owing to the excessive amount of fat. However, surgeons do not agree since they are used to subdividing the last category into other three subcategories: the severe-obese (>40, <45), the morbid-obese (>45, <50) and the super-obese (>50).

Actually the BMI is part of category of 3 or 4 parameters currently used in order to express how far from the ideal weight a person truly is. The BMI seems to be the least relevant of them all since it does not take into account the differences in body structure. That means that if by chance a person weighs a lot due to the presence of increased muscular mass, the index is not capable of distinguishing it from qualitatively different mass (fat) and thus declares the person overweight/obese. Other parameters seem to be of much more accuracy. The waist/hip ration is a calculation that compares the amplitude of one's body at the waist and at the hip. It can be measured as a frontal W/H ratio (from the front of the individual by drawing two parallel lines at the waist level and at the hip level and then dividing the waist line length by the hip line length) or as normal W/H ratio (dividing circumferences). This kind of parameters also takes into consideration the fat distribution profile, accordingly women can have larger hips and thus a smaller value (ideally 0.7) while man should have hips just a bit wider that the waist (ideal value around 0.9).

It seems that the W/H ratio was applied in esthetics, as it is considered to be an expression of female attractiveness. Yet this is questionable since different ethnicities and thus cultures value different ideal ratios. For example Asians prefer wider hips and thus lower ratio values while south American males are more attracted to higher ratio-scoring women. It was then inferred that subconsciously this is a way of estimating fertility; since fat is usually deposited in the hips in case of women, in geographic areas where food availability is not constant throughout the year, subconsciously energy storage is evaluated as a pro-creative argument. Thus females with larger hips and lower ratios will be granted for the most beautiful in the area. On the other hand, in areas with constant food supplies excessive hip fat storage is perceived as useless, and thus men focus on the waist seeing it as an expression of fertility, thus higher W/H ratios are favored in men's preferences.

Although W/H ratio is more accurate as the BMI in expressing the degree of distance from the ideal weight (and as well proved to be a good cardiovascular risk predictor) an even more accurate measurement is provided by other 2 parameters: the body fat percentage and total body fat. These can be estimated by various methods like body impedance calculation or hydrostatic weighting. It is generally accepted that a percentage above 25 for males and above 33 for women represents the onset of obesity. Some believe that as much as 10.8% can be attributed to the normal fat percentage difference between the two sexes in favor of women. Clinically the percentage is usually approximated by the following formula:

Abdominal circumference has also been used in order to asses obesity, generally so-called central-obesity since it is the time associated with highest mortality. Central obesity differs from peripheral obesity in the way it is distributed. Central means that fat is stored around internal organs and mainly around the belly, thus measuring the abdominal circumference yields its severity. A circumference above 102 cm in men and 88 cm in women seems to be associated with highly increased risks.

Although obesity is associated with increased incidence of a variety of conditions like some types of cancer, type II diabetes mellitus, cardiovascular disease, osteoarthritis and sleep apnea syndrome, it is still a leading cause of death that can be prevented. One of the questions that troubled the mind of specialist was why some populations tend to react in a severer way to obesity than others; although still not fully understood the perception of the fact made Japanese lower the BMI level for obesity to 25 and the Chinese to 27, as an expression of how Asians are hyper-influenced by obesity. Caucasians to be the most adapted to excessive bodyweight. No matter the impact however, obesity still reduces the life expectancy by various degrees according to the obesity-class that the individual belongs to. There is however a so-called "Obesity survival paradox" showing that in case of heart failure patients that tend to lose weight as an expression of chronic disease survival is longer in case of pre-conditional class I obese patients than in normal-weight categories. The advantage is lost however in case of upper classes since the overweight impact outruns the benefit. Although not generally applicable this paradox is worth considering when thinking of chronic, consuming diseases like TB, cancer, or HIV-infection. Maximum life expectancy is estimated between 22.5-25 kg/square meters (BMI).

The cause of obesity is widely debated. As with most disease there are genetic factors well implied into the matter. But under no circumstance are they to be blamed alone. Except for extremely severe cases of obesity which are the consequence of preexisting defects in genes that code for adipokines (for example leptin), most cases are a combination between a genetic susceptibility (more or less pronounced) and environmental factors. The environmental factors most implied are dietary excess and sedentary lifestyle.

The problem with obesity is not solely the esthetics but its potential of generating side-effects. These complications are either due to excessive volume of the fat cells that existed before (hypertrophy, accounting for osteoarthritis, social stigmatization and sleep apnea syndrome) or due to an increase in the number of fat cells that comes later in the evolution of obesity (hyperplasia, accounting for certain types of cancer, diabetes mellitus, non-alcoholic fatty liver disease and cardiovascular effects). At the same time the high volume and number of cells generate a higher amount of adipokines than necessary and subsequently induce a so-called pro-inflammatory state; that is fats hurt the vascular endothelium and increase the propensity to clotting, statistically increasing the chance of thrombosis.

As mentioned before obesity is of rare pure genetic cause and thus rarely occurs by itself. The galloping incidence of the condition in the 20th century lead to the creation of a term, "metabolic syndrome" that comprises obesity as well as another few factors frequently associated. All these describe a clinical picture of an individual at high risk for complications mentioned abode. The metabolic syndrome consists of an association of a few from the following list: obesity, particularly the "apple"-type (men's pattern of getting fat, also called central adiposity); elevated blood pressure; high blood triglycerides and low HDL-cholesterol (the "good cholesterol") and resistance to insulin. Having only one of the aforementioned does not place you in the metabolic syndrome group but does increase your overall risk of severe health problems. An association of either 3 is called metabolic syndrome. In case of 2 present risk factors it is debatable.

Beside genes, and the two basic environmental factors, recent studies summoned another ten general risk factors for developing obesity. Insufficient sleep, endocrine disruptors (chemical compounds distributed in foods generally that have the possibility to interfere with the organism's endocrine system and perturb it), use of some medication, natural selection of individuals with higher BMI and assorted mating (the fact the obese tend to hang among themselves due to stigmatization) are a few of them.

The changes in diet that favored increased incidences in obesity everywhere refer altering the balance between carbohydrate, fat and protein. The so-called western type of diet is a direct effect of this; fast-food is the most eloquent example of a food high in fat and carbohydrate and low on protein. The reason for this is the attempt to supply an ever-growing population's caloric needs with far less food than before. Thus subsidizing of corn, wheat, rice and soy by the US government supported this industry and lead to food becoming cheaper and more accessible to citizens. A qualitative assessment of the same type of food now and 20 years ago (cheeseburger) yielded the fact that it is has now almost doubled its caloric energy in spite of modestly increasing its size. Since people tend to eat irrationally until they feel that they cannot anymore (until their stomach is full) this means that 20 years later they found themselves provided with a doubled quantity of energy for the same culinary habits so eventually they all started to become fat.

The sedentary lifestyle factor was increasingly observed in children whose parents were found to be rather permissive with their offspring's time spent in front of the TV. Studies have shown a parallelism between growing number of hours spent watching TV and the degree of obesity installed in children; this is of no surprise as the day has 24 hours in case of everybody, so couch potatos can't allocate any more time for physical exercise.

The management of obesity usually addresses changing lifestyle since more than 90% of the cases are an expression of an altered one. This means that as first measure fat people are supposed to have a change in the diet and to get more exercise. Four types of diets exist so far each of them proving more or less efficient; it also seems that the type of diet most efficient for an individual depends on his previous dietary habits; since the diet does include some of his previous food options this might be easily tolerated and the rate of success might improve. The four types of diet are: low-carbohydrate, low-fat, low-calorie and a derivative of the last, very-low-calorie. It is easy to assume what each of them relies upon. The main idea is to exclude as much as possible the causatives of high amounts of energy in the diet, in order to allow the individual to consume from his own storage in order to lose weight. Dieting alone is not effective unless combined with exercise.

Exercising is sometimes difficult for obese individuals since they are neither used to it nor do they have and out of the common disease to perform it, since it might be strenuous. Physical strain is supposed to rely on muscles and thus to urge the body to use a lot of energy in order to power them up; since it is combined with diet and energy cannot be provided by daily intake, the body will drain the fat storage for stamina. It was previously proved that the larger the muscles implied in the training are, the more efficient it is. Since the largest muscle group in the whole body is the cvadriceps muscle in the thigh that produces the extension of the leg on the thigh, it seems that exercises like walking, running or swimming are the most effective. At the same time the quantity of physical effort is of crucial importance. Little exercise is really not effective, and at the same time exercise by itself without dieting is rarely effective. Very intense muscular effort however does prove to accelerate the weight loss progress; a caution must be issued: in case of a very low on calorie diet the fastened weight loss can lead to the diminishment of muscular mass by loss of proteins. This is due to the fact that the body, which is actually starved increases its protein burnout (thing which is normally not permitted) in order to be able to sustain itself; that is why a very low calorie diet is usually performed under the close surveillance of a physician.

Out of the medication currently approved by the FDA for human use in case of obese patients two can be mentioned, orlistat (Xenical) and sibutramine (Meridia). Their mechanism of action is completely different. Orlistat acts as a pancreatic lipase inhibitor, thus not allowing this crucial enzyme to break down lipids into absorbable forms in the small intestine. This leads to iatrogenic and wished for lipid malabsorption in somewhat simulating a pancreatic insufficiency. The weight loss yielded is not that spectacular and there is fear that loss of highly valuable lipids such as cholesterols or the lipid-soluble vitamins can have potentially severe side-effects on the body. The second substance, sibutramin acts similar to some new antidepressant drugs that inhibit the degradation of activatory neurotransmitters in the brains and thus maintain a lively tonus of the central nervous system. It does this somewhere in the hypothalamus where the hunger and satiety centers of the brain are located and constantly informs the brain that an individual is satisfied with his food intake. The effectiveness is not spectacular but just like orlistat it does yield some weight loss.

The last and most discussed methods are surgical ones. It seems that their immediate efficacy is the greatest, and still they do maintain efficacy on a long period of time if the individual proves to cooperate enough. However the potentially numerous complications make it to be a last resort choice, only in case of patients with a BMI of above 40, in whose situation both dieting plus exercise and medication have failed to induce weight loss. The two main mechanisms that are behind these procedures are: the decrease in stomach volume in order to physically determine the individual to eat less and the gastric bypass in which the stomach is shunted; it is functionally and anatomically excluded from the GI tract, and food is left to enter the intestine unprocessed thus leading to poor absorption of nutrients and low caloric intake. Gastric volume reduction surgery includes adjustable gastric banding and vertical banding gastroplasty. While banded interventions are reversible, the gastric bypass isn't. Some other surgical means of addressing the problem include liposuction, more for the esthetic outcome than for a prolonged period of time weight loss, and the gastric balloon. This is a device entered via endoscopic route that is inflated with a fluid and occupies a large part of the stomach in order for the individual to have a limited storage room for food, and for satiety to arise faster.