on the atkins diet you're suppose to eat alot of veggies- but not fruits for two weeks becasue fruits are acctually high in natural sugar. well- definately don't pick a diet you can't stick to because that's no good. sit-ups and leg lifts are good exersizes but only work the muscles and don't burn very much calories and carbs and fat. do some cardio work everyother day and alternate between that and the sit-ups and things. go out for a brisk walk and build it up to a jog or do some tae-bo or something interesting like that. you need cardio exersize becasue it's great for your cardio system and it burns more then just floor work and weight lifting. good luck!