My approach is to have something light (like a banana on toast, or some cereal) about 20 minutes before, and avoid anything heavy for at least two and ideally three hours before.
If I run in the morning, I have a snack, run, and have breakfast when I get back.
If I run after work, I have a snack, run, and eat dinner when I get back.
I always run after work (I admire anyone that can get up early in the morning!) and try and eat regular snacks throughout the day.
7.10am Breakfast - 1 weetabix, scoop of museli, low fat yoghurt and orange juice
10.30am - 1 large chopped carrot and 4 cherry tomatoes
11.45 - handful of grapes
1pm - spinich, chicken and salsa wrap
2pm - apple or cereal bar
4.30pm - banana
5.45pm - Start running!
7.15pm Tea - fish/chicken, veggies, rice/pasta/potatoes
A trainer told me that you should treat your metabolism like a fire - stoke it regularly with snacks to keep it at its optimum, big meals dampen it down and make you feel sluggish. Personally, the banana gives me great energy but if I eat it too close to running, I get a terrible stitch. Any earlier than around an hour, I don't get the energy. You have to do what feels right for you!
Hope this is of some help!