The way to be fit and healthy are from many thing.You should change some habit in your daily life.
First,about food this is the most important thing that you should prepare you must eat healthy food,drink enough water at least 8 glasses,not eat at night,shouldn't keep snack in your home.
Second,about exercise regularly 2-3 day a week,try to move on your body during the day
If you do all of this you will be healthy and fit.