Making Sense Of The Obesity Paradox

Health experts often warn us of the harmful effects of overweight and obesity, and encourage us to maintain a healthy weight. Most of us are aware that having a normal body mass index (BMI), which is a measure of body fat based on body weight and height, is one of the best ways to prevent the development heart disease, diabetes and stroke. This is because of the great body of evidence that links these chronic diseases, including certain types of cancer, to obesity, a condition that is becoming an epidemic worldwide.

Some scientists, however, have discovered an “obesity paradox,” wherein obesity seems to have a protective effect on patients who are suffering from heart failure. Researchers from the Baylor College of Medicine in Houston, Texas, recently published the results of their study in the Journal of the American College of Cardiology, which suggests that compared to normal-weight patients who had heart failure, obese and overweight patients were less likely to die of the disease.

What Is The Obesity Paradox?

Studies show that obesity is a major risk factor for people to develop heart disease and suffer from a heart attack. However, some researchers have observed that an obese person who has just had a heart attack is more likely to survive the event than a normal weight or underweight person.

There have been dozens of studies that seem to suggest that overweight or moderately obese patients, as indicated by their body mass index (BMI) are more likely to survive cardiovascular disease, as well as other chronic conditions like diabetes and kidney disease than normal weight or even underweight individuals with similar diseases. BMI is a measure of body fat, based on your height and weight.

One meta-analysis reviewed the results of 36 different studies on coronary heart disease and found that patients with BMIs between 25 and 30 (categorized as "overweight") have a lower risk of death from heart disease compared to patients with BMIs between 18 and 25 (categorized as "normal weight"). Furthermore, those who were obese (BMI > 30) or severely obese (BMI > 40) had lower chances of death from any chronic disease compared with those who had normal BMIs.

See Also: Can You Be Healthy And Obese?

Some of the possible explanations offered for this paradoxical phenomenon include:

• Coronary heart disease occurs earlier in life among obese individuals and their young age helps them survive a cardiac event.
• Patients who are underweight or of normal weight might have heart disease because of certain genetic factors, while overweight/obese patients may acquire the disease from lifestyle factors. Genetic predisposition to heart disease may leave patients in worse condition than those who got sick from their unhealthy habits.
• Doctors might tend to give better medical care to overweight/obese people, which may lead doctors to be more diligent in prescribing medications at higher doses than for patients with normal weight.

However, whether the obesity paradox is real or just a fallacy remains to be discovered, since no biological basis has been identified and other experts doubt the validity of conclusions made by its proponents.

Is The Obesity Paradox Real?

Can obesity offer protection from death when a person suffers a heart attack? Some experts do not believe that having excess body fat prevents a morbid outcome in patients with heart disease, or that obesity itself offers protection against dying during a cardiac event.

One study involving almost 48,000 patients who have had heart surgery found that those who have a greater lean body mass have a lower risk of death from a cardiac event. The study, which was led by Dr. Carl Lavie of the John Ochsner Heart and Vascular Institute, estimated both the lean mass percentage (which consists of the bone, muscle, and organs) and body fat percentage of each patient and compared their disease outcomes. The study concluded that it is the lean body mass, and not the fat that may be protecting patients during a cardiovascular event.

Dr Jonathan Myers, another research scientist and clinical professor at the Stanford University School of Medicine also believes that instead of measuring BMI alone, scientists must also consider visceral fat and abdominal girth (waist circumference), which are associated with high metabolic risk and are a better predictor of disease. Like other investigators who have done extensive research, Myers also says that a person’s physical fitness level must be considered, since the obesity paradox is not often seen among individuals who are physically fit.

He therefore believes that there is no sense for people to pack on pounds to achieve the paradox effect of obesity.

Fat But Fit?

Some people believe that one can be fat but fit, but a large study published in the Journal of the American College of Cardiology shows otherwise. The study, which followed more than 2,500 British government workers for 20 years, found that participants who were obese but apparently healthy at the start of the study were eight times more likely to become unhealthy after two decades compared to non-obese participants. This was shown clinically by parameters such as high cholesterol, high triglyceride, high blood pressure, high blood sugar, and insulin resistance. These are all risk factors involved in the development of metabolic disorders and chronic diseases such as heart disease, diabetes and stroke. On the other hand, those who lost weight at the end of the study period were more likely to be healthier than those who did not shed pounds.

See Also: Are Weight Loss Products Beneficial?

The long-running Whitehall II study suggests that although an obese person can start out being fit while young, gaining more weight or remaining obese as one grows older can eventually lead to lack of health. Experts would therefore advise 'healthy obese' people to focus on having a healthy lifestyle, to look for ways to adopt better eating habits and to become more physically active.