Excess body fat is bad for your health, but we all need at least a little fat.
"Fat cells are probably the most maligned element of the human body," says John B. Allred, Ph.D., professor emeritus of nutrition at Ohio State University and co-author of the book Taking the Fear Out of Eating. "Few of us realize that they play an important role in establishing and maintaining good health. Ironically, the more we know about how fat cells function, the more we can keep them -- and our weight problems -- in line."
Fat cells, also known as adipocytes, store excess energy from foods as fat. Fat is stored at in the form of fatty acids called triglycerides. Adipose tissue, or a group of fat cells, is found between the skin and muscle (subcutaneous) and in the main body cavities (visceral), primarily in the abdominal cavity.
Some people may have more fat cells than others, but the number of fat cells isn't the main factor determining whether a person becomes overweight. The primary influence on obesity seems to be genetic. People who tend to become overweight simply aren't very good at burning up calories; instead they store them as fat, Dr. Allred says.
Some parents mistakenly believe that they can prevent their children from developing fat cells by restricting food in the child's early years, says Dr. Allred. This is a dangerous practice. Children need a certain amount of fat in the diet for brain and nerve cell development. In some cases, children on restricted diets have suffered from failure to thrive.
As triglycerides are stored within a cell, the "fat blob" inside the cell expands, increasing the cell's diameter. If enough fat cells in a body region enlarge this way, that part of the body begins to look fat.
Weight loss occurs when you use more energy each day than you take in through foods. When food does not supply all the energy you need, fat stores are used as an energy source. When you lose weight by reducing your calorie intake, about 75 to 85 percent of the loss is fat and 15 to 25 percent is lean tissue and water.
The triglycerides stored in fat cells act primarily as energy reserves, Dr. Allred says. "When our muscles and liver use up their available supply of glycogen [a sugar that is the body's main energy source] during strenuous exercise, stored fats are the next source tapped," he explains.
Fat cells have several other roles, as well. They cushion and protect vital organs, insulate the body against heat loss, secrete chemicals that play a part in appetite and other processes, protect nerve tissue and help regulate the menstrual cycle in women .
Beware of ads that beckon you to remove "cellulite" with creams, lotions or devices, Dr. Allred warns. Truth is, he says, cellulite doesn't exist.
"We all have heard that 'cellulite' is a different kind of fat and therefore it, and the skin dimpling it supposedly causes, can be eliminated with special treatments," Dr. Allred explains. "This is incorrect; there is only one type of fat. Dimpling occurs when enlarging fat cells pull down on the surrounding connective tissue, causing a loss of elasticity."
The formula for obesity is simple: When the number of calories you eat exceeds your daily energy requirement, the excess is stored as fat. To eliminate unwanted flab, create an energy deficit.
© 2013 Main Line Health