Obesity is defined as the increased accumulation of fat due to caloric intake that exceeds caloric use. Overweight is an increase in body weight above the desirable height/weight ratio.

The Body Mass Index (BMI) is an index to determine whether an individual is at or above the ideal weight. BMI is estimated in the following manner: the weight of the person divided by his height squared (weight /height2). Overweight is defined as a BMI between 25 to 30 kg/m2 and obesity as a BMI over 30 kg/m2.

Besides the overall measurement of body weight and fat, the specific distribution of fat on a person’s body is a major characteristic in obesity and can predict cardiovascular and metabolic complications. These distribution patterns are determined by looking at the body circumference in the waist and hips and calculating the waist-hip relationship. In patients with abdominal obesity or obesity in the upper part of the body, the ratio relationship is 0.85. A very high waist/hip relationship indicates a higher tendency to coronary diseases, stroke and death. A waist/hip relationship below 0.76 is associated with increased adipose tissue in the hips and lower part of the body. This value correlates with higher incidents of cardiovascular disease.

Causes of obesity

There are multiple causes of obesity. These include:

Family predisposition.

Scientific studies have demonstrated that genetic influence is a major factor regarding overall body fat and distribution.

Eating disorders.

Most obese people show unhealthy eating behaviors usually consuming an excessive quantity of calories compared to the amount of calories they use. At the same time obese people show a lower feeling of satisfaction with meals and a lower metabolism of the calories they take in. This is commonly known as “slow metabolism”. Internal signals from substances such as glucose, fatty acids, glycerol, etc. and hormones such as insulin, somatostatin, etc. rule over hunger, feelings of fullness and appetite and are involuntary. On the other hand, eating behavior is influenced by external factors such as social environment and environmental conditions relating to cold or hot weather, among others. Obese people will eat in excess due to a greater response to thoughts about food, to visual and olfactory stimuli and to the preference for sugary or fatty flavors in foods.

Use of energy.

Obese people use less energy than they consume. The absence of or a major reduction in physical activity is often associated with an increase in caloric intake which causes an accumulation of fat.

Psychosocial factors.

In adult obese people, anxiety and depression are common triggers of excessive caloric intake. Home is a major determining factor for eating habits and can foster obesity. Mothers of obese children are overprotective and express their love and devotion by offering food for non- nutritional reasons.


There is a growing trend in the prevalence of overweight and obese people.

In the United States, for instance, 5.8% of men and 8.3% of women are obese. Stress associated with the increased consumption of fats and carbohydrates –very common in current times– combine to increase the tendency towards more people becoming overweight and obese. Obesity has become an epidemic of the 21st century.

Medical complications

Being overweight or obese is associated with major medical and metabolic diseases.


The likelihood of suffering from hypertension is 3 to 5 times higher in obese people than it is in those who are not. The excess of adipose tissue increases cardiac work and thus triggers an inappropriately high cardiac volume per minute. There is a close relationship between obesity, hypertension and an increase in blood insulin levels (the hormone needed for the utilization of glucose in blood). It is important to point out that losing weight is associated with a significant reduction in blood pressure and a reduction in the need to take medication for hypertension.


Obese people produce high levels of insulin on an empty stomach. The incidence of diabetes in obese patients is 3 times higher than it is in patients who are not obese. The increase in insulin is directly proportional to body weight. This increase in insulin is due to the lower sensitivity of peripheral tissues to insulin that has either been produced by the body or from external sources such as medicine. This resistance to insulin generates an intolerance to glucose, which increases its levels in blood. The close relationship between obesity and diabetes is demonstrated by the fact that 80% of patients with diabetes mellitus who are not insulin-dependent are obese. Low-calorie diets, weight reduction and exercise improve sensitivity to insulin and help normalize the values of glucose in blood.

Atherosclerosis and coronary disease.

Obese people tend to be more prone to changes in their blood lipid levels. Obese people tend to demonstrate a reduction in HDL cholesterol (known as good cholesterol) as well as an increase in total cholesterol levels, LDL cholesterol (or bad cholesterol) and triglycerides. The incidence of these changes is 2 times higher in obese persons. Individuals with a high BMI show a higher risk of having coronary disease and generalized atherosclerosis. In addition, there is a strong relationship between abdominal distribution of body fat and the risk of developing a cardiovascular disease.


Obesity is associated with an increase in the incidence of breast cancer, possibly by creating a favorable environment for the progress of tumors. Endometrial cancer is 5 times more frequent in obese women. Obese men have a higher risk of having prostate cancer.

Gall bladder disease.

The prevalence of gallstones in obese women is 3 times higher than in those who are not. The main factor contributing to this could be the balance between bile salts, lecithin and cholesterol in bile.

Sleep apnea.

In extreme obesity, an increase in adipose tissue located in the abdomen and upper part of the body makes breathing more difficult. Sleep apnea occurs with a 1.25% incidence rate among male adults and it is some 25 times more frequent in patients with severe obesity. Patients show daytime drowsiness and episodes of apnea (absence in the entrance of air through the nose and mouth) longer than 10 seconds during sleep.


Excessive weight induces the degeneration of joints and fosters precocious osteoarthritis. A loss of weight improves problems of the muscular- skeletal apparatus.


The importance of a healthy diet, reducing fat intake as well as overall caloric intake and starting and maintaining an exercise routine cannot be underestimated. These critical but simple steps are key towards improving patient quality of life and mortality rate by eliminating many of the problems we have discussed above.