You work hard to get yourself as toned as one of those bodies on the label of a package of health food. Except behind you are these dimples that won't go away, no matter what you do.

You have cellulite.

Where did you get it?

Blame yourself. You picked the wrong parents. Cellulite runs in families. You were born female. (The percentage of men who have visible cellulite is in the single digits.)

Cellulite, dimpling mainly on the back of the thighs, hips and behind, is fat. Those areas are a stubborn place for fat — relatively spongy, fibrous and less interactive with the blood supply — which means they're good for insulation and absorption of impact, but fat there doesn't go away as fast with exercise and diet.

Cellulite is only a menace because having it seems to upset the culturally romanticized view that silky smooth skin is a sign of youthfulness and health.

Even that is a misconception, considering that cellulite starts appearing at about age 12 to 14 and has no more effect on overall health than any other fat, according to the American Academy of Dermatologists.

Once it develops, its progress is individual. Because cellulite is fat, it can grow or shrink with the amount of fat you accumulate. And as humans age, their top layer of skin thins, making cellulite more visible.

Women comprise about 95 percent of people who complain of cellulite, according to doctors.

Dr. Thomas Wright, an internist who does some cosmetic procedures, described the origins of cellulite.

Skin connects to the inside of the body by strands of connective tissue. Without those strands, the skin would slide around.

The fat that is just beneath the skin for shock absorption, insulation and storage mingles with the connective tissue.

Cellulite becomes visible when the connective tissue breaks loose unevenly and allows the fat at those spots to expand, Wright said.

The frustrating part is that cellulite usually hangs on after all the other fat has gone away. That's when it drives people to doctors. Doctors say the U.S. Food and Drug Administration has approved treatment for the temporary removal of cellulite, but nothing for permanent removal.

The No. 1 treatment is to maintain a good diet that reduces fat throughout your body. Wright said that cellulite fat is the last fat the body loses.

Some creams might work temporarily, usually just because they tighten the skin, doctors say. But there's no way to reduce fat beneath the skin with cream on top of the skin, experts say.

Dr. Ronald J. Chod, chief executive of Aeterna Medical Spa, which specializes in nonsurgical cosmetic procedures in the St. Louis area, said his business treats cellulite with VelaSmooth, an FDA-approved technology.

On its Web site, manufacturer Syneron says VelaSmooth treatments use a laserlike device that heats subcutaneous fat, which is responsible for the dimpling. Through that heat and tissue mobilization, Syneron said, the procedure smoothes and "recontours" the skin. Most patients have no side effects, although a few experience temporary skin irritation.