I've never heard that, and if it does cause an increase to the metabolic rate, it'd likely be temporary and fairly easily counteracted by the munchies and lethargy.

Metabolic rate varies from person to person and depends on weight, activity level, caloric intake, muscle mass, thyroid function, age, etc. I suspect that changes to metabolic rate would vary from person to person, just like with anything else that's ingested--like food.