. >> reporter: for compulsive eaters like tara, recognizing she had an addiction was like a thunder clap to her brain. >> that makes me feel good. >> reporter: in her new book, the doctor offers a prescription to get on the way to recovery. three ms. mind, memory and mouth. we reveal the snacks we crave most. for me it's cheese. >> you're a fatty girl that also likes salt. >> what did you call me. >> what did you call me? >> you like fatty w salt. >> reporter: for now, we head to send tlal park. it's time to medicate. >> i'm in control. i'm powering up my brain. >> this is not a new age moment. this is hard core neuroscience. you're powering up the brain to stay vigilant, say no and rein in impulses. >> reporter: step two. instead of ice cream we try a chocolate protein smoothie. >> there's not sugar in it. >> peanut butter. one of my favorite things. step three, move your muscles. >> she rewards her brain with endorphins. >> now if i have too much sugar i get violently sick. >> new science shows you increase the size of the brain because you stimulate brain growth. when you do things li