Disclosed is a technique, and apparatus, for increasing flow of heat into or out of a person's body, wherein, simultaneously with the application of a heating or cooling medium to the body, the flow of blood to a surface region of the body is increased. The technique, and apparatus, can be used to increase burning (and rate of burning) of calories in the person's body, with resulting loss of fat and corresponding weight loss, by applying a cooling medium simultaneously with increasing flow of blood to a surface region of the body.