Ash is 35, while Abhishek is 32 and he is supposed to be shaving his head for the film Ravana which is definitely going to make him look even younger. It seems Mani Ratnam wanted Abhishek to sport the new lean look for his film Ravana , where he wanted him to have a lean warrior look and a different hairstyle too. That's why Abhi has trimmed his hair real short and has lost 15 kgs.
When asked as to how did he manage to loose so much weight he said that he has been spending most of his time in the gym. It seems when he is not on the sets he is spending his time working out. He has also done yoga. According to sources Ash is taking care of his diet and is making sure that he is eating less oily stuff and more of fruits and vegetables at every interval.