I feel it is a personal answer. Some people who have slow metabolisms and/or @ a low bodyweight need to add cardio in addition to any type of weight training in their regimens to burn additional calories to meet their goals. This is regardless of being on or off IMO.
It comes down to simple math: calories in vs calories out.
1. lift weights enough to stimulate muscle growth.
2. reduce your calories enough to lose .5-1.5 pounds per week (assuming you aren't overly fat, then shoot for 2)
3. once you get down to a caloric intake equal to 10x your bodyweight and weight loss stops, you need to increase calories burned. Adding more weightlifting will just overtrain you and shoot yourself in the foot. Therefore you need to do intense cardio to burn 400-600 calories per session as many times per week possible to give you the weekly deficit to keep losing weight when weight loss slows down due to low bodyfat levels and bodyweight.
This has been my reality as well as many others. You can get stuck in limbo when #1 and 2 plateaus, or you can tell your genetics to fuck off by working your ass off to reach your desired body composition goals.
Good Luck.