Good Morning, Don t sell hypnosis short. It should not be the ONLY answer as making permanent nutritional and lifestyle changes are necessary to maintain any significant amount of weight, hypnosis can be a great asset. As far as telling the body it is exercising while it is sleeping, I don t know if you were told this specifically, but that would be up to the hypnotherapist to discuss. I do know you can tell the mind something under hypnosis that can make a difference in your behavior, stress levels and sleep among others. I recommend that you give it a try if you are dealing with a reputable health professional/MD, but recognize it will not be your only solution to total and permanent weight loss and fitness. Have a Great Day. Kathryn, Your Online Nutritionist