In any other context, some of these tests would be bad jokes or ludicrous charades. What makes the popularity of these fake tests a serious matter is that patients are suffering and are eager for solutions to their chronic health problems, but they not getting help from qualified physicians. They are vulnerable to anyone who seems at all plausible and offers tests and treatments for food problems. The subject is invited to hold a glass vial containing the test substance and the examiner tests the strength of the other arm that is outstretched. Sometimes the subject is instructed to hold the vial over the body part to be tested.
Weakness is interpreted as a food reaction, and the subject is advised to avoid the test substance.
Variations on this theme have emerged. As a party game, muscle testing could be fun, but anyone who believes this is a valid test of body physiology needs to be re-educated in biology. The more imaginative Vega meter readers will tell you they can balance levels of certain substances in your body by doing meter readings and prescribing drops. You sign up for a series of tests and treatments and the cost can vary from hundreds to thousands of dollars. Vega meters are scams.