crashing your calories is a sure fire way to feel like crap all day and also it will damage your metabolism
i hate these crash diets because they do not work long term.
diet is extremely important though, you have to eat clean so you feel good and you are not getting in excess calories
as far as cardio, bodybuilders hate it. but what you are describing isn't really cardio at all. cardio to me is running. if you went jogging for 30 minutes a day you would not only lose a ton of body fat but you would strengthen your heart and feel great. forget the stupid stationary bike and forget the stupid the elliptical. when i was an endurance athlete i was running over 35 miles per week, i would eat whole pizza's everyday and i would never gain body fat. i stayed in the mid single digits and stayed very lean.
if you do a jog for lets say 30 minutes for a dude your size/male you are going to burn a solid 300+ calories.
on the flip side of the arguement lets say you busted your ass in the gym for an hour and then after you decide to go to chikFila or subway and eat a 1000 calorie meal. (yes a sub meal with a coke from subway is 1000+ calories) you just blew your entire workout and then some. i see this mistake A LOT. so the point is you better workout consistently AND eat good otherwise you are wasting your time. hence why most people spin their wheels with fitness and go nowhere
also did you know someone who works a hard labor job will burn up to 1200 more calories over the course of the day vs. someone like an accountant who sits on their ass? so if you work a desk job like most of us these days you better get in your exercise to make up for all that sitting
but here is the bottom line answer to your question. it is better to eat a balanced diet and utilize daily exercise.. then simply cutting off calories and being lazy. you will have a stronger heart and better endurance that way, and you will feel good too. you aren't going to get fat off oatmeal, sweet potatoes, fruit and brown rice.. those are POWER foods you utilize for energy when you workout.