America’s battle against obesity
A complicated condition with serious consequences
Howard Manly | 10/10/2013, 6 a.m.
It is understandable, then, that fat is the target of much research. So significant is this issue that a sub-specialty in obesity medicine has been developed by the American Board of Obesity Medicine.
What has been discovered is that, surprisingly, fat is a physiologically complex organ that communicates with other organs, including the brain and the liver. But not all fat is the same and is differentiated by location.
Abdominal, or visceral, fat is centered at and above the waist giving a person an apple shape. Unlike the external fat that can be grasped, visceral fat is internal and lies between the organs in the abdomen. As opposed to fat found in the thighs, for instance, visceral fat is biologically active and can increase the risk of cardiovascular disease and type 2 diabetes.
As the co-director of the Weight Center at Massachusetts General Hospital, Dr. Kathleen Corey knows a thing or two about obesity. She specializes in liver disease and says obesity and the liver are more highly linked than most patients, including some doctors, tend to realize.
The liver is the second largest organ in the body and does yeoman’s work. It produces cholesterol to help carry fats through the body; it clears the blood of drugs and other toxins; and it helps the immune system resist infections.
It also gains weight. As a person accumulates fat, so does the liver. It stands to reason that the rise in BMIs across the country is accompanied by bigger livers.
Nonalcoholic fatty liver disease (NAFLD) is the buildup of fat in the liver of people who do not drink excessively. NAFLD is common — roughly 20 to 40 percent of the population is affected — and, for the most part, causes no symptoms. It is usually silent and can be missed. “It’s often an incidental find,” explained Corey.
The best treatment for NAFLD is weight loss, exercise and healthy eating. Vitamin E and some medications for diabetes have been helpful, but new medications are in the works. NAFLD is reversible in the early stages.
If not reversed or stabilized, NAFLD can progress to the more serious nonalcoholic steatohepatis (NASH), which can result in cirrhosis of the liver. It is estimated that, with increasing obesity rates, the incidence of a NASH and cirrhosis from NASH will increase.
The connection between liver disease and obesity is one of the reasons Corey agrees with the AMA’s position that obesity is a disease.
“Obesity is complicated,” she explained. “The cause is multi-factorial. Many people need help to control it.”
She acknowledged that some people with a BMI in the obesity range are healthy. But she said, “We still worry that they are at risk.”
The cause of obesity is pretty straight forward. A person consumes more calories than the body requires. The unused calories are stored as fat. Unfortunately, the body has no limit to adding fat and unburned calories are consistently stored. Furthermore, fat cells cannot be destroyed once formed. A weight loss program will reduce their size, but not the number.