Nocebo:
A nocebo effect is said to occur when negative expectations of the patient regarding a treatment cause the treatment to have a more negative effect than it otherwise would have. For example, when a patient anticipates a side effect of a medication, they can suffer that effect even if the “medication” is actually an inert substance. Both placebo and nocebo effects are presumably psychogenic, but they can induce measurable changes in the body. [Wikipedia]
Noted in “How a positive mind really can create a healthier body,” David Robson, NewScientist (25 August 2018, paywall):
Placebos are inert pills used in most clinical drug trials. The participants are divided randomly into two groups: half take the drug being tested, the rest, for comparison, take an identical-looking sugar pill. With no active ingredient, the placebo shouldn’t have any effects. Yet it often brings about measurable changes, triggering the release of natural painkillers and lowering blood pressure, for example – all because of people’s expectations. Patients sometimes reap these benefits even when they know they are taking the placebo (see “Everyday placebos”). On the downside, our expectations of a pill can also produce side effects, including nausea and skin rashes. This is the placebo effect’s “evil” twin, the nocebo effect (see “The science of voodoo”).
One practical result is to not consider a “diet” to be abstemious, but instead learn to adore every bite.
