If you ate really healthy (vegan) and didnt eat past 3pm and ran 4 days a week....

[meanair]

it depends but you know i should know your limits, it can be dangerous. find a trainer

[RachaelM]

it depends what size you are now, and how healthy (ie how many calories) and how far and fast you run (running at a 5mph pace is much different than an 8mph pace, and 2 miles is different than 10). I lost 30 lbs in 4 weeks last year with just a little exercise (40 minutes on elliptical 5 days a week, lifting weights 30 minutes 2x week) and a reasonably healthy diet (mostly vegetarian). You can eat in the evening, btw, that no eating in the evening is a myth. It's overall calories that count. Aim for 1200-1600 a day, be sure to get enough protein. Good luck.