I am very conscious about my physique.  I always avoid chocolates, chips, sodas as much as i can, beers, icecreams, cakes, fries and so on.  basically i try to avoid food with lot of sugar and oil.  i however drink juice, which has sugar in it.  it is suggested to eat in every four hours if possible.  like somone mentioned above, take heavy breakfast, then lunch and take light dinner, at least 2 hrs before you go to bed. 

you need to watch what you are eating and then follow some exericise.  in my case, i try to work out at least 2-3 days a week.  i am keeping my body in pretty good shape until now and i am happy with it. 

i know we all are busy so we need to look at what is possible for us to do.  so, best advise would be right food and little bit of exercise in your free time.