Dust on furniture may be bad news for waistlines  . But it's far too early to add dusting to a weight-loss plan. Dietary fats and other materials that make up indoor dust can send a signal to human fat cells, telling them to grow. That process, in turn, might slow the body's rate of burning energy. Such changes could add to any weight problems a person might have. "We don't know what that means to long-term health and certain diseases yet," says Heather Stapleton, one of the study's authors. But she notes that her team's findings also raise a question of whether pollutants in dust might play some role in the growing, global problem of obesity  . Stapleton and her colleagues collected dust from homes and offices. Studies found that some materials in the dust could turn on a protein   called PPAR-gamma 1. It's found in many human tissues. Turning this protein on can cause fat cells to grow. Researchers think this protein may be involved in obesity. But a second study now finds evidence that certain fats are mostly to blame. Cooking oils may send out some of these fats into the air, where they eventually find their way into house dust. Or, the authors say, the fats might enter house dust as part of the hair or skin cells shed   by people or pets. "While the findings are amazing," says Mitchell Lazar, another study author, "these findings need to be taken as very limited." Indeed, he adds several cautions about how the findings should be understood. "For one thing, people eat these fats in foods all of the time. That is likely to be a lot more than would be consumed from indoor dust," he said. What do we know about PPAR-gamma 1?   _
It comes from dust. It leads to weight gain. It can help get rid of dust. It only appears in human bodies.