Placebos aren't just for research: Studies increasingly show that treatments with no active ingredients can work as well as—or even better than—"real" therapies. In one such study, some hotel employees were told they were getting good exercise at work; they lost weight, while fellow workers who hadn't gotten the message didn't. Another study found that subjects told their food was high in calories felt full faster than compatriots told they were eating low-cal food, the Wall Street Journal reports.
It's not just about the metabolism, of course: Some 30% to 45% of depression patients, for example, saw benefits from placebos. What's more, such treatments seem to perform well even when subjects know what they're getting. Patients with irritable bowel syndrome felt better after taking pills they were told lacked any active properties and just worked on the mind. "Evidence is that placebo changes not the underlying biology of an illness, but the way a person experiences or reacts to an illness," notes an expert. Indeed, some doctors already prescribe over-the-counter drugs for their placebo benefits; researchers are looking into better harnessing the treatment's power. (Read more placebo stories.)