Obesity  

Obesity has reached epidemic proportions in the U.S. and other parts of the industrialized world. Even in developing countries, obesity is escalating rapidly.

More than 60% of adults in the US are now overweight or obese.

What is even more alarming is the rapid increase in the prevalence of obesity among children and adolescents. The rate of overweight children and adolescents has more than doubled in the U.S. since the 1970s.  Approximately 14% of U.S children and adolescents are now seriously overweight.

Obesity is now a well known risk factor for diabetes, high blood pressure, heart attacks, stroke, gall stones, degenerative arthritis and certain cancers such as breast, colon, uterus, ovary, kidney and prostate cancer.

In 2003, the American Cancer Society published its analysis of sixteen years of follow-up of 900,000 U.S. adults who were free of cancer at enrollment in the study in 1982. There were 57,145 deaths from cancer during this period.

Obesity was significantly associated with a higher rate of death due to cancer of the breast, uterus, cervix, ovary, esophagus, liver, gallbladder, pancreas, kidney, and prostate. This study was published in 2003 in the New England Journal of Medicine.

There are two types of obesity: 

1.  Generalized obesity

2.   Abdominal obesity

You have abdominal obesity if your waist-line is more than 35 inches for females or more than 38 inches for males. Slang words, such as  “spare tire” or “love handles” are often used to describe abdominal obesity.

Most individuals with generalized obesity also have abdominal obesity. However, some individuals, especially Asians, may have abdominal obesity without generalized obesity.  Therefore, the current WHO definition of obesity may underestimate obesity in the Asian population.

This issue was emphasized in a recently published study from Singapore, in which many Chinese, Malaysians and Indians, who were non-obese according to WHO definition, were found to have excess fat accumulation and increased risk factors for cardiovascular disease. My clinical experience is in line with the findings in this study.

At the Jamila Diabetes and Endocrine Center, most of our Asian Type 2 diabetics are non-obese, according to WHO criteria.

What is the link between obesity and Insulin Resistance Syndrome?

Individuals with abdominal obesity suffer from a disease process known as insulin resistance.

In normal individuals, one of the actions of insulin is to keep fat inside the fat cells. In people with abdominal obesity, there is resistance to this action of insulin, which results in an accumulation of fat (free fatty acids) in the blood, which then leads to high triglycerides and low HDL cholesterol (the good cholesterol).

These cholesterol abnormalities lead to narrowing of the blood vessels.

People with abdominal obesity usually have low HDL cholesterol (good cholesterol), below 55mg/dl in females and less than 45 mg/dl in males, and a high triglycerides level (above 150 mg/dl). 

Another action of insulin is to keep blood glucose in the normal range all the time. People with abdominal obesity develop resistance to this action of insulin.

Consequently, the body produces more and more insulin in order to keep blood glucose in the normal range. After a number of years, the body is unable to keep up with this mounting insulin resistance.

At this point, blood glucose starts rising, initially in the post-meal state only and later on, even in the fasting state.

An oral glucose tolerance test can diagnose these different stages of abnormal glucose metabolism.