Do something about it starting today! (and do yourself a favor, don't go on a fad diet just eat fresh fruits and veggies and no processed foods) to achieve this look you must use weights. You can start out with body weight at first if you need it.
YES, you do need to eat after a workout!The 14 Best Things To Eat After A Workout. These supply nutrients like proteins, carbohydrates, vitamins and minerals which help restore your energy and build muscles after a workout.