Depends on how quickly you want to lose weight, and whether that's your only goal. If, as a 150 pound male, your RMR is about 1500 kcal/day, and you eat at lea

Depends on how quickly you want to lose weight, and whether that's your only goal. If, as a 150 pound male, your RMR is about 1500 kcal/day, and you eat at least 1000 kcal/day (anything less probably isn't healthy - you do need to supply your body with nutrition, and also avoid going into starvation mode) - then you are running a 500kcal/day deficit - about 3500 kcal/week, or 1 pound of weight loss. If you want to lose any more than that, eating less, outside of a metabolic lab environment, is probably not going to be effective (you either have your RMR drop as your body goes into starvation mode, or you end up binge eating as your body reacts to the massive deficit of calories). This only allows for increased caloric output - and it's relatively simple to do 500 kcal/additional aerobic exercise/day - an hour of brisk walking, with maybe 30 minutes of stair climbing does the trick. This gets you from 1 pound of weight loss a week, to 2 pounds, and has the additional benefit of increasing your VO2 Max. This doesn't even touch on the importance of resistance strength training exercise, and how key that is to maintaining a healthy body while dropping weight - it's all to easy to turn into a lightweight flabby weak person by just not eating/exercising.