not just heroin addicts. they were heroin addicts in vietnam. when they came back to the united states the environment changed. and so did their likelihood of keeping up that bad habit. so what does this mean for you? maybe it's ice cream that you eat every night. well try and disrupt your environment just a little bit tonight. if you're going to eat that ice cream, maybe eat it while standing up. or eat it with your left hand instead of your right hand. sometimes it means letting go of people who are enpowering the bad habits. it means avoiding place where's the bad habits occur. think about a smoker. take a different way to work. the point is disrupt the environment just a little bit and you're more likely to break the bad habits. >> all right, sanjay. i'm left-handed. i'll eat my ice cream with my right hand. to find out more how to make positive changes and stick to them visit our website, cnn.com/health. and good luck. man-crush, duck face and